1
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Ma Z, Zeng H, Luo H, Liu Z, Jiang Y, Aoki Y, Wang W, Itoh Y, Lyu M, Cui Y, Yun SH, Hill EM, Wei S. Slow rupture in a fluid-rich fault zone initiated the 2024 Mw 7.5 Noto earthquake. Science 2024:eado5143. [PMID: 38963875 DOI: 10.1126/science.ado5143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 06/25/2024] [Indexed: 07/06/2024]
Abstract
The 2024 moment magnitude (Mw) 7.5 Noto Peninsula (Japan) earthquake caused devastation to communities and was generated by a complex rupture process. Using space geodetic and seismic observations, we show that the event deformed the peninsula with a peak uplift reaching 5 m at the west coast. Shallow slip exceeded 10 m on an offshore fault. Peak stress drop was greater than 10 MPa. This devastating event began with a slow rupture propagation lasting 15-20 s near its hypocenter, where seismic swarms had surged since 2020 due to lower-crust fluid supply. The slow start was accompanied by intense high-frequency seismic radiation. These observations suggest a distinct coseismic slip mode reflecting high heterogeneity in fault properties within a fluid-rich fault zone.
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Affiliation(s)
- Zhangfeng Ma
- Earth Observatory of Singapore, Nanyang Technological University, Singapore
| | - Hongyu Zeng
- Earth Observatory of Singapore, Nanyang Technological University, Singapore
- Asian School of the Environment, Nanyang Technological University, Singapore
| | - Haipeng Luo
- Earth Observatory of Singapore, Nanyang Technological University, Singapore
- Department of Earth and Space Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Zemin Liu
- The Institute of Geophysics, China Earthquake Administration, Beijing, China
| | - Yu Jiang
- Earth Observatory of Singapore, Nanyang Technological University, Singapore
| | - Yosuke Aoki
- Earthquake Research Institute, The University of Tokyo, Tokyo, Japan
| | - Weitao Wang
- The Institute of Geophysics, China Earthquake Administration, Beijing, China
| | - Yuji Itoh
- Earthquake Research Institute, The University of Tokyo, Tokyo, Japan
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, Univ. Gustave Eiffel, ISTerre, 38000 Grenoble, France
| | - Mingzhe Lyu
- Asian School of the Environment, Nanyang Technological University, Singapore
| | - Yan Cui
- School of Earth Sciences and Engineering, Hohai University, Nanjing, China
| | - Sang-Ho Yun
- Earth Observatory of Singapore, Nanyang Technological University, Singapore
- Asian School of the Environment, Nanyang Technological University, Singapore
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore
| | - Emma M Hill
- Earth Observatory of Singapore, Nanyang Technological University, Singapore
- Asian School of the Environment, Nanyang Technological University, Singapore
| | - Shengji Wei
- Earth Observatory of Singapore, Nanyang Technological University, Singapore
- Asian School of the Environment, Nanyang Technological University, Singapore
- Key Laboratory of Deep Petroleum Intelligent Exploration and Development, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
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2
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Goebel THW, Schuster V, Kwiatek G, Pandey K, Dresen G. A laboratory perspective on accelerating preparatory processes before earthquakes and implications for foreshock detectability. Nat Commun 2024; 15:5588. [PMID: 38961092 PMCID: PMC11222383 DOI: 10.1038/s41467-024-49959-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 06/26/2024] [Indexed: 07/05/2024] Open
Abstract
Dynamic failure in the laboratory is commonly preceded by many foreshocks which accompany premonitory aseismic slip. Aseismic slip is also thought to govern earthquake nucleation in nature, yet, foreshocks are rare. Here, we examine how heterogeneity due to different roughness, damage and pore pressures affects premonitory slip and acoustic emission characteristics. High fluid pressures increase stiffness and reduce heterogeneity which promotes more rapid slip acceleration and shorter precursory periods, similar to the effect of low geometric heterogeneity on smooth faults. The associated acoustic emission activity in low-heterogeneity samples becomes increasingly dominated by earthquake-like double-couple focal mechanisms. The similarity of fluid pressure increase and roughness reduction suggests that increased stress and geometric homogeneity may substantially shorten the duration of foreshock activity. Gradual fault activation and extended foreshock activity is more likely observable on immature faults at shallow depth.
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Affiliation(s)
- Thomas H W Goebel
- University of Memphis, Center for Earthquake Research and Information, Memphis, TN, USA.
| | - Valerian Schuster
- German Research Centre for Geosciences (GFZ), Section 4.2 Geomechanics and Scientific Drilling, Potsdam, Germany
| | - Grzegorz Kwiatek
- German Research Centre for Geosciences (GFZ), Section 4.2 Geomechanics and Scientific Drilling, Potsdam, Germany
| | - Kiran Pandey
- University of Memphis, Center for Earthquake Research and Information, Memphis, TN, USA
| | - Georg Dresen
- German Research Centre for Geosciences (GFZ), Section 4.2 Geomechanics and Scientific Drilling, Potsdam, Germany
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3
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Volpe G, Collettini C, Taddeucci J, Marone C, Pozzi G. Frictional instabilities in clay illuminate the origin of slow earthquakes. SCIENCE ADVANCES 2024; 10:eadn0869. [PMID: 38941467 PMCID: PMC11212734 DOI: 10.1126/sciadv.adn0869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 05/23/2024] [Indexed: 06/30/2024]
Abstract
The shallowest regions of subduction megathrusts mainly deform aseismically, but they can sporadically host slow-slip events (SSEs) and tsunami earthquakes, thus representing a severe hazard. However, the mechanisms behind these remain enigmatic because the frictional properties of shallow subduction zones, usually rich in clay, do not allow earthquake slip according to standard friction theory. We present experimental data showing that clay-rich faults with bulk rate-strengthening behavior and null healing rate, typically associated with aseismic creep, can contemporaneously creep and nucleate SSE. Our experiments document slow ruptures occurring within thin shear zones, driven by structural and stress heterogeneities of the experimental faults. We propose that bulk rate-strengthening frictional behavior promotes long-term aseismic creep, whereas localized frictional shear allows slow rupture nucleation and quasi-dynamic propagation typical of rate-weakening behavior. Our results provide additional understanding of fault friction and illustrate the complex behavior of clay-rich faults, providing an alternative paradigm for interpretation of the spectrum of fault slip including SSEs and tsunami earthquakes.
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Affiliation(s)
- Giuseppe Volpe
- Dipartimento di Scienze della Terra, La Sapienza Università di Roma, Rome, Italy
| | - Cristiano Collettini
- Dipartimento di Scienze della Terra, La Sapienza Università di Roma, Rome, Italy
- Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
| | | | - Chris Marone
- Dipartimento di Scienze della Terra, La Sapienza Università di Roma, Rome, Italy
- Department of Geoscience, Pennsylvania State University, University Park, PA, USA
| | - Giacomo Pozzi
- Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
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4
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Cheng Y, Bürgmann R, Allen RM. 3D architecture and complex behavior along the simple central San Andreas fault. Nat Commun 2024; 15:5390. [PMID: 38918370 PMCID: PMC11199709 DOI: 10.1038/s41467-024-49454-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 06/05/2024] [Indexed: 06/27/2024] Open
Abstract
The central San Andreas Fault (CSAF) exhibits a simple linear large-scale fault geometry, yet seismic and aseismic deformation features vary in a complex way along the fault. Here we investigate fault zone behaviors using geodetic observation, seismicity and microearthquake focal mechanisms. We employ an improved focal-mechanism characterization method using relative earthquake radiation patterns on 75,164 Ml ≥ 1 earthquakes along a 2-km-wide, 190-km-long segment of the CSAF, from 1984 to 2015. The data reveal the 3D fine-scale structure and interseismic kinematics of the CSAF. Our findings indicate that the first-order spatial variations in interseismic fault creep rate, creep direction, and the fault zone stress field can be explained by a simple fault coupling model. The inferred 3D mechanical properties of a mechanically weak and poorly coupled fault zone provide a unified understanding of the complex fine-scale kinematics, indicating distributed slip deficits facilitating small-to-moderate earthquakes, localized stress heterogeneities, and complex multi-scale ruptures along the fault. Through this detailed mapping, we aim to relate the fine-scale fault architecture to potential future faulting behavior along the CSAF.
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Affiliation(s)
- Yifang Cheng
- State Key Laboratory of Marine Geology, Tongji University, Shanghai, China.
- Department of Earth and Planetary Science, University of California, Berkeley, CA, USA.
- Berkeley Seismological Laboratory, University of California, Berkeley, Berkeley, CA, USA.
- School of Ocean and Earth Science, Tongji University, Shanghai, China.
| | - Roland Bürgmann
- Department of Earth and Planetary Science, University of California, Berkeley, CA, USA
- Berkeley Seismological Laboratory, University of California, Berkeley, Berkeley, CA, USA
| | - Richard M Allen
- Department of Earth and Planetary Science, University of California, Berkeley, CA, USA
- Berkeley Seismological Laboratory, University of California, Berkeley, Berkeley, CA, USA
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5
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Zhang K, Wang Y, Luo Y, Zhao D, Wang M, Yang F, Wu Z. Complex tsunamigenic near-trench seafloor deformation during the 2011 Tohoku-Oki earthquake. Nat Commun 2023; 14:3260. [PMID: 37277348 DOI: 10.1038/s41467-023-38970-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/22/2023] [Indexed: 06/07/2023] Open
Abstract
The near-trench coseismic rupture behaviour of the 2011 Tohoku-Oki earthquake remains poorly understood due to the scarcity of near-field observations. Differential bathymetry offers a unique approach to studying offshore coseismic seafloor deformation but has a limited horizontal resolution. Here we use differential bathymetry estimates with improved horizontal resolutions to investigate near-trench coseismic slip behaviours in the 2011 Tohoku-Oki earthquake. In the main rupture region, a velocity-strengthening behaviour in the shallow fault is observed. By contrast, the seafloor uplift decreases towards the trench, but the trend inverts near the backstop interface outcrop, revealing significant off-fault deformation features. Amongst various competing off-fault effects observed, we suggest that inelastic deformation plays a predominant role in near-trench tsunami excitation. Large trench-bleaching rupture is also observed immediately north of 39°, delimiting the northern extent of the main rupture region. Overall, striking spatial heterogeneity of the shallow rupture behaviour is revealed for the region.
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Affiliation(s)
- Kai Zhang
- College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao, China
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
- Key Laboratory of Ocean Geomatics, Ministry of Natural Resources, Qingdao, China
| | - Yanru Wang
- College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao, China
| | - Yu Luo
- College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao, China
| | - Dineng Zhao
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
- Key Laboratory of Ocean Geomatics, Ministry of Natural Resources, Qingdao, China
| | - Mingwei Wang
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
| | - Fanlin Yang
- College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao, China.
- Key Laboratory of Ocean Geomatics, Ministry of Natural Resources, Qingdao, China.
| | - Ziyin Wu
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China.
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6
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Brooks BA, Goldberg D, DeSanto J, Ericksen TL, Webb SC, Nooner SL, Chadwell CD, Foster J, Minson S, Witter R, Haeussler P, Freymueller J, Barnhart W, Nevitt J. Rapid shallow megathrust afterslip from the 2021 M8.2 Chignik, Alaska earthquake revealed by seafloor geodesy. SCIENCE ADVANCES 2023; 9:eadf9299. [PMID: 37126563 PMCID: PMC10132754 DOI: 10.1126/sciadv.adf9299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 03/21/2023] [Indexed: 05/03/2023]
Abstract
The shallower portions of subduction zone megathrust faults host Earth's most hazardous tsunamigenic earthquakes, yet understanding how and when they slip remains elusive because of challenges making seafloor observations. We performed Global Navigation Satellite System Acoustic seafloor geodetic surveys before and ~2.5 months after the 29 July 2021 Mw (moment magnitude) 8.2 Chignik, Alaska, earthquake and determine ~1.4 meters cumulative co- and post-seismic horizontal displacement ~60 kilometers from the megathrust front. Only for the 2011 Mw 9 Tohoku event have closer subduction zone earthquake displacements been observed. We estimate ~2 to 3 meters of megathrust afterslip shallower than 20 kilometers, a portion of the megathrust on which both inter- and co-seismic slip likely had occurred previously. Our analysis demonstrates that by 2.5 months, shallower and deeper moment had effectively equilibrated on the megathrust, suggesting that its tsunamigenic potential remains no more elevated than before the earthquake.
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Affiliation(s)
- Benjamin A. Brooks
- Earthquake Science Center, U.S. Geological Survey, Moffett Field, CA, USA
| | - Dara Goldberg
- National Earthquake Information Center, Geological Hazards Science Center, U.S. Geological Survey, Golden, CO, USA
| | | | - Todd L. Ericksen
- Earthquake Science Center, U.S. Geological Survey, Moffett Field, CA, USA
| | - Spahr C. Webb
- Lamont-Doherty Earth Observatory, Palisades, NY, USA
| | - Scott L. Nooner
- University of North Carolina Wilmington, Wilmington, NC, USA
| | | | | | - Sarah Minson
- Earthquake Science Center, U.S. Geological Survey, Moffett Field, CA, USA
| | - Robert Witter
- Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA
| | - Peter Haeussler
- Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA
| | | | - William Barnhart
- National Earthquake Information Center, Geological Hazards Science Center, U.S. Geological Survey, Golden, CO, USA
| | - Johanna Nevitt
- Earthquake Science Center, U.S. Geological Survey, Moffett Field, CA, USA
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7
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Yao L, Ma S, Di Toro G. Coseismic fault sealing and fluid pressurization during earthquakes. Nat Commun 2023; 14:1136. [PMID: 36890136 PMCID: PMC9995344 DOI: 10.1038/s41467-023-36839-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 02/16/2023] [Indexed: 03/10/2023] Open
Abstract
Earthquakes occur because faults weaken with increasing slip and slip rate. Thermal pressurization (TP) of trapped pore fluids is deemed to be a widespread coseismic fault weakening mechanism. Yet, due to technical challenges, experimental evidence of TP is limited. Here, by exploiting a novel experimental configuration, we simulate seismic slip pulses (slip rate 2.0 m/s) on dolerite-built faults under pore fluid pressures up to 25 MPa. We measure transient sharp weakening, down to almost zero friction and concurrent with a spike in pore fluid pressure, which interrupts the exponential-decay slip weakening. The interpretation of mechanical and microstructural data plus numerical modeling suggests that wear and local melting processes in experimental faults generate ultra-fine materials to seal the pressurized pore water, causing transient TP spikes. Our work suggests that, with wear-induced sealing, TP may also occur in relatively permeable faults and could be quite common in nature.
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Affiliation(s)
- Lu Yao
- State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing, China.
| | - Shengli Ma
- State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing, China
| | - Giulio Di Toro
- Dipartimento di Geoscienze, Università di Padova, Padova, Italy.,Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
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8
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Weng H, Ampuero JP. Integrated rupture mechanics for slow slip events and earthquakes. Nat Commun 2022; 13:7327. [DOI: 10.1038/s41467-022-34927-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 11/09/2022] [Indexed: 11/29/2022] Open
Abstract
AbstractSlow slip events occur worldwide and could trigger devastating earthquakes, yet it is still debated whether their moment-duration scaling is linear or cubic and a fundamental model unifying slow and fast earthquakes is still lacking. Here, we show that the rupture propagation of simulated slow and fast earthquakes can be predicted by a newly-developed three-dimensional theory of dynamic fracture mechanics accounting for finite rupture width, an essential ingredient missing in previous theories. The complete spectrum of rupture speeds is controlled by the ratio of fracture energy to energy release rate. Shear stress heterogeneity can produce a cubic scaling on a single fault while effective normal stress variability produces a linear scaling on a population of faults, which reconciles the debated scaling relations. This model provides a new framework to explain how slow slip might lead to earthquakes and opens new avenues for seismic hazard assessment integrating seismological, laboratory and theoretical developments.
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9
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Premus J, Gallovič F, Ampuero JP. Bridging time scales of faulting: From coseismic to postseismic slip of the Mw 6.0 2014 South Napa, California earthquake. SCIENCE ADVANCES 2022; 8:eabq2536. [PMID: 36149958 PMCID: PMC9506709 DOI: 10.1126/sciadv.abq2536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 08/04/2022] [Indexed: 05/31/2023]
Abstract
Transient fault slip spans time scales from tens of seconds of earthquake rupture to years of aseismic afterslip. So far, seismic and geodetic recordings of these two phenomena have primarily been studied separately and mostly with a focus on kinematic aspects, which limits our physical understanding of the interplay between seismic and aseismic slip. Here, we use a Bayesian dynamic source inversion method, based on laboratory-derived friction laws, to constrain fault stress and friction properties by joint quantitative modeling of coseismic and postseismic observations. Analysis of the well-recorded 2014 South Napa, California earthquake shows how the stressing and frictional conditions on the fault govern the spatial separation between shallow coseismic and postseismic slip, the progression of afterslip driving deep off-fault aftershocks, and the oblique ribbon-like rupture shape. Such inferences of stress and frictional rheology can advance our understanding of earthquake physics and pave the way for self-consistent cross-scale seismic hazard assessment.
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Affiliation(s)
- Jan Premus
- Department of Geophysics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - František Gallovič
- Department of Geophysics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - Jean-Paul Ampuero
- Université Côte d’Azur, IRD, CNRS, Observatoire de la Côte d’Azur, Géoazur, France
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10
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Rupture process of the 2021 M7.4 Maduo earthquake and implication for deformation mode of the Songpan-Ganzi terrane in Tibetan Plateau. Proc Natl Acad Sci U S A 2022; 119:e2116445119. [PMID: 35658079 DOI: 10.1073/pnas.2116445119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Significance The Songpan-Ganzi terrane lies in the central-east of the Tibetan Plateau, which was considered a stable block in some tectonic models. Its deformation mode is of crucial importance for understanding the evolutionary history and seismic hazard of the plateau. The recent Maduo earthquake occurred inside the terrane. We resolve a bilateral rupture process with distinct super- and subshear rupture modes for this event. We also find that pervasive folding structures that are aligned by shear deformation in the current Songpan-Ganzi terrane are responsible for the seismic wave anisotropy and shear strain orientation in its upper crust. Its deformation mode can be classified as distributed simple shear, which receives shear loads from side walls and produces internal earthquakes.
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11
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Aseismic slip and recent ruptures of persistent asperities along the Alaska-Aleutian subduction zone. Nat Commun 2022; 13:3098. [PMID: 35654827 PMCID: PMC9163073 DOI: 10.1038/s41467-022-30883-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 05/13/2022] [Indexed: 11/26/2022] Open
Abstract
The frictional properties and slip behaviors of subduction thrusts play a key role in seismic and tsunami hazard assessment, especially in weakly coupled “seismic gaps”. Here, we rely on GPS observations in the Shumagin Gap of the Aleutian subduction zone to derive the slip distribution of the 2020 Mw 7.8 Simeonof Island, Alaska earthquake and of the subsequent afterslip during the first 87-day period. Our modeling results show that the mainshock ruptured at depths of ∼30–40 km beneath Simeonof Island. Kinematic and stress-driven models indicate that the afterslip occurred both updip and downdip of the mainshock rupture. Physically plausible locking models derived from interseismic GPS velocities suggest that the 2020 Simeonof and 2021 Mw 8.2 Chignik earthquakes ruptured persistent asperities on the subduction thrust. We infer that there are several additional persistent asperities at depths of 20–50 km west ∼157°W. However, it is still uncertain whether there are additional locked asperities at shallow depths because of the current lack of geodetic observations close to the trench. Physically plausible interseismic asperity models determined from GPS velocities suggest that the 2020 Mw 7.8 Simeonof and 2021 Mw 8.2 Chignik earthquakes ruptured distinct persistent asperities on the Alaska-Aleutian subduction zone
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12
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Intermittent lab earthquakes in dynamically weakening fault gouge. Nature 2022; 606:922-929. [PMID: 35650443 DOI: 10.1038/s41586-022-04749-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 04/08/2022] [Indexed: 11/08/2022]
Abstract
Large and destructive earthquakes on mature faults in Earth's crust occur as slip in a layer of a fine granular material-fault gouge-produced by comminution during sliding1,2. A range of insights into the frictional resistance of faults-one of the main factors controlling earthquake nucleation, dynamic propagation and arrest, and hence the destructive ground shaking of earthquakes2,3-has been obtained in experiments with spatially uniform slip imposed in small samples2,4-21. However, how various features of gouge friction combine to determine spontaneous progression of earthquakes is difficult to study in the lab owing to substantial challenges with sample sizes and adequate imaging22. Here, using lab experiments, we show that spontaneously propagating dynamic ruptures navigate a fault region with fine rock gouge through complex, intermittent slip processes with dramatic friction evolution. These include repeated arrest of rupture propagation caused by friction strengthening at lower slip rates and dynamic earthquake re-nucleation enabled by pronounced rapid friction weakening at higher slip rates consistent with flash heating8,12,23. The spontaneous repeated weakening and strengthening of friction in fine rock gouge highlights the fundamental dependence of friction on slip rate and associated processes, such as shear heating, localization and delocalization of shear, and dilation and compaction of the shear layer6,7,9-21. Our findings expand experimental support9,11 of the concept that co-seismic weakening may enable earthquake rupture to break through stable fault regions24,25, with substantial implications for seismic hazard.
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13
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Churchill RM, Werner MJ, Biggs J, Fagereng Å. Afterslip Moment Scaling and Variability From a Global Compilation of Estimates. JOURNAL OF GEOPHYSICAL RESEARCH. SOLID EARTH 2022; 127:e2021JB023897. [PMID: 35865712 PMCID: PMC9287082 DOI: 10.1029/2021jb023897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/22/2022] [Accepted: 04/02/2022] [Indexed: 05/26/2023]
Abstract
Aseismic afterslip is postseismic fault sliding that may significantly redistribute crustal stresses and drive aftershock sequences. Afterslip is typically modeled through geodetic observations of surface deformation on a case-by-case basis, thus questions of how and why the afterslip moment varies between earthquakes remain largely unaddressed. We compile 148 afterslip studies following 53 M w 6.0-9.1 earthquakes, and formally analyze a subset of 88 well-constrained kinematic models. Afterslip and coseismic moments scale near-linearly, with a median Spearman's rank correlation coefficient (CC) of 0.91 after bootstrapping (95% range: 0.89-0.93). We infer that afterslip area and average slip scale with coseismic moment as M o 2 / 3 and M o 1 / 3 , respectively. The ratio of afterslip to coseismic moment (M rel ) varies from <1% to >300% (interquartile range: 9%-32%). M rel weakly correlates with M o (CC: -0.21, attributed to a publication bias), rupture aspect ratio (CC: -0.31), and fault slip rate (CC: 0.26, treated as a proxy for fault maturity), indicating that these factors affect afterslip. M rel does not correlate with mainshock dip, rake, or depth. Given the power-law decay of afterslip, we expected studies that started earlier and spanned longer timescales to capture more afterslip, but M rel does not correlate with observation start time or duration. Because M rel estimates for a single earthquake can vary by an order of magnitude, we propose that modeling uncertainty currently presents a challenge for systematic afterslip analysis. Standardizing modeling practices may improve model comparability, and eventually allow for predictive afterslip models that account for mainshock and fault zone factors to be incorporated into aftershock hazard models.
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Affiliation(s)
| | - M. J. Werner
- School of Earth SciencesUniversity of BristolBristolUK
| | - J. Biggs
- School of Earth SciencesUniversity of BristolBristolUK
| | - Å. Fagereng
- School of Earth and Environmental SciencesCardiff UniversityCardiffUK
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14
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Liu YK, Ross ZE, Cochran ES, Lapusta N. A unified perspective of seismicity and fault coupling along the San Andreas Fault. SCIENCE ADVANCES 2022; 8:eabk1167. [PMID: 35196076 PMCID: PMC8865773 DOI: 10.1126/sciadv.abk1167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 12/30/2021] [Indexed: 06/14/2023]
Abstract
The San Andreas Fault (SAF) showcases the breadth of possible earthquake sizes and occurrence behavior; in particular, the central SAF is a microcosm of such diversity. This section also exhibits the spectrum of fault coupling from locked to creeping. Here, we show that the observations of aseismic slip, temporal clustering of seismicity, and spatial variations in earthquake size distributions are tightly connected. Specifically, the creep rate along the central SAF is shown to be directly proportional to the fraction of nonclustered earthquakes for the period 1984-2020. This relationship provides a unified perspective of earthquake phenomenology along the SAF, where lower coupling manifests in weaker temporal clustering, with repeating earthquakes as an end-member. This new paradigm provides additional justification for characterizing the northwest ∼75 kilometers of the creeping segment as a transition zone, with potential implications for seismic hazard.
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Affiliation(s)
- Yuan-Kai Liu
- Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, USA
| | - Zachary E. Ross
- Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, USA
| | | | - Nadia Lapusta
- Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, USA
- Department of Mechanical and Civil Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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15
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Bedford JD, Faulkner DR, Lapusta N. Fault rock heterogeneity can produce fault weakness and reduce fault stability. Nat Commun 2022; 13:326. [PMID: 35039494 PMCID: PMC8763890 DOI: 10.1038/s41467-022-27998-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 12/15/2021] [Indexed: 11/09/2022] Open
Abstract
Geological heterogeneity is abundant in crustal fault zones; however, its role in controlling the mechanical behaviour of faults is poorly constrained. Here, we present laboratory friction experiments on laterally heterogeneous faults, with patches of strong, rate-weakening quartz gouge and weak, rate-strengthening clay gouge. The experiments show that the heterogeneity leads to a significant reduction in strength and frictional stability in comparison to compositionally identical faults with homogeneously mixed gouges. We identify a combination of weakening effects, including smearing of the weak clay; differential compaction of the two gouges redistributing normal stress; and shear localization producing stress concentrations in the strong quartz patches. The results demonstrate that geological heterogeneity and its evolution can have pronounced effects on fault strength and stability and, by extension, on the occurrence of slow-slip transients versus earthquake ruptures and the characteristics of the resulting events, and should be further studied in lab experiments and earthquake source modelling.
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Affiliation(s)
- John D Bedford
- Rock Deformation Laboratory, Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, UK.
| | - Daniel R Faulkner
- Rock Deformation Laboratory, Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Nadia Lapusta
- Department of Mechanical and Civil Engineering, Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA.,Seismological Laboratory, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
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16
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Dynamic rupture initiation and propagation in a fluid-injection laboratory setup with diagnostics across multiple temporal scales. Proc Natl Acad Sci U S A 2021; 118:2023433118. [PMID: 34916283 PMCID: PMC8713790 DOI: 10.1073/pnas.2023433118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2021] [Indexed: 11/18/2022] Open
Abstract
Fluids are known to trigger a broad range of slip events, from slow, creeping transients to dynamic earthquake ruptures. Yet, the detailed mechanics underlying these processes and the conditions leading to different rupture behaviors are not well understood. Here, we use a laboratory earthquake setup, capable of injecting pressurized fluids, to compare the rupture behavior for different rates of fluid injection, slow (megapascals per hour) versus fast (megapascals per second). We find that for the fast injection rates, dynamic ruptures are triggered at lower pressure levels and over spatial scales much smaller than the quasistatic theoretical estimates of nucleation sizes, suggesting that such fast injection rates constitute dynamic loading. In contrast, the relatively slow injection rates result in gradual nucleation processes, with the fluid spreading along the interface and causing stress changes consistent with gradually accelerating slow slip. The resulting dynamic ruptures propagating over wetted interfaces exhibit dynamic stress drops almost twice as large as those over the dry interfaces. These results suggest the need to take into account the rate of the pore-pressure increase when considering nucleation processes and motivate further investigation on how friction properties depend on the presence of fluids.
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17
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Shao Z, Wang W, Liu Q, Pan Z, Liu X, Wang P, Wei W, Feng W, Yin X. Prospects of earthquake physical forecasting under the framework of active-tectonic block theory. CHINESE SCIENCE BULLETIN-CHINESE 2021. [DOI: 10.1360/tb-2021-0968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Hunfeld LB, Chen J, Niemeijer AR, Ma S, Spiers CJ. Seismic Slip-Pulse Experiments Simulate Induced Earthquake Rupture in the Groningen Gas Field. GEOPHYSICAL RESEARCH LETTERS 2021; 48:e2021GL092417. [PMID: 34219831 PMCID: PMC8243972 DOI: 10.1029/2021gl092417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/23/2021] [Accepted: 05/18/2021] [Indexed: 06/13/2023]
Abstract
Rock materials show dramatic dynamic weakening in large-displacement (m), high-velocity (∼1 m/s) friction experiments, providing a mechanism for the generation of large, natural earthquakes. However, whether such weakening occurs during induced M3-4 earthquakes (dm displacements) is unknown. We performed rotary-shear experiments on simulated fault gouges prepared from the source-, reservoir- and caprock formations present in the seismogenic Groningen gas field (Netherlands). Water-saturated gouges were subjected to a slip pulse reaching a peak circumferential velocity of 1.2-1.7 m/s and total displacements of 13-20 cm, at 2.5-20 MPa normal stress. The results show 22%-81% dynamic weakening within 5-12 cm of slip, depending on normal stress and gouge composition. At 20 MPa normal stress, dynamic weakening from peak friction coefficients of 0.4-0.9 to 0.19-0.27 was observed, probably through thermal pressurization. We infer that similar effects play a key role during induced seismic slip on faults in the Groningen and other reservoir systems.
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Affiliation(s)
- Luuk B. Hunfeld
- HPT LaboratoryDepartment of Earth SciencesUtrecht UniversityUtrechtThe Netherlands
- Now at Advisory Group for Economic AffairsThe Netherlands Organization for Applied Scientific Research (TNO)UtrechtThe Netherlands
| | - Jianye Chen
- HPT LaboratoryDepartment of Earth SciencesUtrecht UniversityUtrechtThe Netherlands
- Now at Faculty of Civil Engineering and GeosciencesTechnical University of DelftDelftThe Netherlands
| | - André R. Niemeijer
- HPT LaboratoryDepartment of Earth SciencesUtrecht UniversityUtrechtThe Netherlands
| | - Shengli Ma
- State Key Laboratory of Earthquake DynamicsInstitute of GeologyChina Earthquake AdministrationBeijingChina
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19
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Li D, Liu Y. Cascadia megathrust earthquake rupture model constrained by geodetic fault locking. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200135. [PMID: 33715408 DOI: 10.1098/rsta.2020.0135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/06/2020] [Indexed: 05/25/2023]
Abstract
Paleo-earthquakes along the Cascadia subduction zone inferred from offshore sediments and Japan coastal tsunami deposits approximated to M9+ and ruptured the entire margin. However, due to the lack of modern megathrust earthquake records and general quiescence of subduction fault seismicity, the potential megathrust rupture scenario and influence of downdip limit of the seismogenic zone are still obscure. In this study, we present a numerical simulation of Cascadia subduction zone earthquake sequences in the laboratory-derived rate-and-state friction framework to investigate the potential influence of the geodetic fault locking on the megathrust sequences. We consider the rate-state friction stability parameter constrained by geodetic fault locking models derived from decadal GPS records, tidal gauge and levelling-derived uplift rate data along the Cascadia margin. We incorporate historical coseismic subsidence inferred from coastal marine sediments to validate our coseismic rupture scenarios. Earthquake rupture pattern is strongly controlled by the downdip width of the seismogenic, velocity-weakening zone and by the earthquake nucleation zone size. In our model, along-strike heterogeneous characteristic slip distance is required to generate margin-wide ruptures that result in reasonable agreement between the synthetic and observed coastal subsidence for the AD 1700 Cascadia Mw∼9.0 megathrust rupture. Our results suggest the geodetically inferred fault locking model can provide a useful constraint on earthquake rupture scenarios in subduction zones. This article is part of the theme issue 'Fracture dynamics of solid materials: from particles to the globe'.
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Affiliation(s)
- Duo Li
- Department of Earth and Environmental Sciences, Munich University, Theresienstrasse 41, 80333 Munich, Germany
| | - Yajing Liu
- Department of Earth and Planetary Sciences McGill University, 3450 University Street, Montréal, Québec, Canada
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20
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Aretusini S, Meneghini F, Spagnuolo E, Harbord CW, Di Toro G. Fluid pressurisation and earthquake propagation in the Hikurangi subduction zone. Nat Commun 2021; 12:2481. [PMID: 33931641 PMCID: PMC8087711 DOI: 10.1038/s41467-021-22805-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 03/31/2021] [Indexed: 02/02/2023] Open
Abstract
In subduction zones, seismic slip at shallow crustal depths can lead to the generation of tsunamis. Large slip displacements during tsunamogenic earthquakes are attributed to the low coseismic shear strength of the fluid-saturated and non-lithified clay-rich fault rocks. However, because of experimental challenges in confining these materials, the physical processes responsible for the coseismic reduction in fault shear strength are poorly understood. Using a novel experimental setup, we measured pore fluid pressure during simulated seismic slip in clay-rich materials sampled from the deep oceanic drilling of the Pāpaku thrust (Hikurangi subduction zone, New Zealand). Here, we show that at seismic velocity, shear-induced dilatancy is followed by pressurisation of fluids. The thermal and mechanical pressurisation of fluids, enhanced by the low permeability of the fault, reduces the energy required to propagate earthquake rupture. We suggest that fluid-saturated clay-rich sediments, occurring at shallow depth in subduction zones, can promote earthquake rupture propagation and slip because of their low permeability and tendency to pressurise when sheared at seismic slip velocities.
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Affiliation(s)
- S. Aretusini
- grid.410348.a0000 0001 2300 5064HPHT Laboratory, INGV, Rome, Italy
| | - F. Meneghini
- grid.5395.a0000 0004 1757 3729Department of Earth Sciences, University of Pisa, Pisa, Italy
| | - E. Spagnuolo
- grid.410348.a0000 0001 2300 5064HPHT Laboratory, INGV, Rome, Italy
| | - C. W. Harbord
- grid.83440.3b0000000121901201Department of Earth Sciences, University College London, London, UK
| | - G. Di Toro
- grid.410348.a0000 0001 2300 5064HPHT Laboratory, INGV, Rome, Italy ,grid.5608.b0000 0004 1757 3470Dipartimento di Geoscienze, University of Padua, Padua, Italy
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21
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Fagereng Å, Beall A. Is complex fault zone behaviour a reflection of rheological heterogeneity? PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20190421. [PMID: 33517872 PMCID: PMC7898124 DOI: 10.1098/rsta.2019.0421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/18/2020] [Indexed: 05/26/2023]
Abstract
Fault slip speeds range from steady plate boundary creep through to earthquake slip. Geological descriptions of faults range from localized displacement on one or more discrete planes, through to distributed shearing flow in tabular zones of finite thickness, indicating a large range of possible strain rates in natural faults. We review geological observations and analyse numerical models of two-phase shear zones to discuss the degree and distribution of fault zone heterogeneity and effects on active fault slip style. There must be certain conditions that produce earthquakes, creep and slip at intermediate velocities. Because intermediate slip styles occur over large ranges in temperature, the controlling conditions must be effects of fault properties and/or other dynamic variables. We suggest that the ratio of bulk driving stress to frictional yield strength, and viscosity contrasts within the fault zone, are critical factors. While earthquake nucleation requires the frictional yield to be reached, steady viscous flow requires conditions far from the frictional yield. Intermediate slip speeds may arise when driving stress is sufficient to nucleate local frictional failure by stress amplification, or local frictional yield is lowered by fluid pressure, but such failure is spatially limited by surrounding shear zone stress heterogeneity. This article is part of a discussion meeting issue 'Understanding earthquakes using the geological record'.
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22
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Nakata R, Hori T, Miura S, Hino R. Presence of interplate channel layer controls of slip during and after the 2011 Tohoku-Oki earthquake through the frictional characteristics. Sci Rep 2021; 11:6480. [PMID: 33742049 PMCID: PMC7979718 DOI: 10.1038/s41598-021-86020-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 03/09/2021] [Indexed: 11/29/2022] Open
Abstract
There are significant differences between the middle and southern segments of the Japan Trench in terms of the seismic and aseismic slips on the plate interface and seismic velocity structures. Although the large coseismic slip of the 2011 Tohoku-Oki earthquake was limited to the middle segment, the observed negative residual gravity anomaly area in the southern segment corresponds to the postseismic slip area of the Tohoku-Oki earthquake. A density distribution model can explain the different slip behaviours of the two segments by considering their structural differences. The model indicates that the plate interface in the south was covered with a thick channel layer, as indicated by seismic survey imaging, and this layer resulted in a residual gravity anomaly. Numerical simulations which assumed evident frictional heterogeneity caused by the layer in the south efficiently reproduced M9 earthquakes recurring only in the middle, followed by evident postseismic slips in the south. This study proposes that although the layer makes the megathrust less compliant to seismic slip, it promotes aseismic slips following the growth of seismic slips on the fault in an adjacent region.
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Affiliation(s)
- Ryoko Nakata
- Graduate School of Science, Tohoku University, 6-6, Aramaki-aza-aoba, Aoba-ku, Sendai, 980-8578, Japan.
| | - Takane Hori
- Research and Development Center for Earthquake and Tsunami Forecasting (FEAT), Research Institute for Marine Geodynamics (IMG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Kanazawa-ku, Yokohama, 236-0001, Japan
| | - Seiichi Miura
- Subduction Dynamics Research Center (SDR), Research Institute for Marine Geodynamics (IMG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Kanazawa-ku, Yokohama, 236-0001, Japan
| | - Ryota Hino
- Graduate School of Science, Tohoku University, 6-6, Aramaki-aza-aoba, Aoba-ku, Sendai, 980-8578, Japan
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23
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Kodaira S, Iinuma T, Imai K. Investigating a tsunamigenic megathrust earthquake in the Japan Trench. Science 2021; 371:371/6534/eabe1169. [PMID: 33707238 DOI: 10.1126/science.abe1169] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The 2011 Tohoku-oki earthquake occurred in the Japan Trench 10 years ago, where devastating earthquakes and tsunamis have repeatedly resulted from subduction of the Pacific plate. Densely instrumented seismic, geodetic, and tsunami observation networks precisely recorded the event, including seafloor observations. A large coseismic fault slip that unexpectedly extended to a shallow part of megathrust fault was documented. Strong lateral variations of the coseismic slip near the trench were recorded from marine geophysical studies, along with a possible cause of these variations. The seismic activities in east Japan are still higher than those before the earthquake, and crustal deformation is still occurring. Although the recurrence probability of a great earthquake (magnitude = ~9) in the Japan Trench in the near future is very low, a large normal fault earthquake seaward of the Japan Trench is a concerning possibility.
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Affiliation(s)
- Shuichi Kodaira
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan
| | - Takeshi Iinuma
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan
| | - Kentaro Imai
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan
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24
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Tomography of the source zone of the great 2011 Tohoku earthquake. Nat Commun 2020; 11:1163. [PMID: 32127532 PMCID: PMC7054414 DOI: 10.1038/s41467-020-14745-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 01/28/2020] [Indexed: 11/24/2022] Open
Abstract
The mechanism and rupture process of the giant 2011 Tohoku-oki earthquake (Mw 9.0) are still poorly understood due to lack of permanent near-field observations. Using seismic arrival times recorded by dense seismograph networks on land and at ocean floor, we determine a detailed seismic tomography model of the megathrust zone beneath the Tohoku forearc. Our results show that the coseismic slip of the 2011 Tohoku-oki earthquake initiated at a boundary between a down-dip high-velocity anomaly and an up-dip low-velocity anomaly. The slow anomaly at shallow depths near the Japan trench may reflect low-rigidity materials that are close to the free surface, resulting in large slip and weak high-frequency radiation. Our new tomographic model can account for not only large slip near the trench but also weak high-frequency radiation from the shallow rupture areas. Using data recorded by a new seafloor seismic network, the authors reveal the detailed 3D structure of the source zone of the great 2011 Tohoku-oki earthquake, which sheds new light on the mechanism of the great earthquake and tsunami.
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25
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Rabinowitz HS, Savage HM, Polissar PJ, Rowe CD, Kirkpatrick JD. Earthquake slip surfaces identified by biomarker thermal maturity within the 2011 Tohoku-Oki earthquake fault zone. Nat Commun 2020; 11:533. [PMID: 31988278 PMCID: PMC6985169 DOI: 10.1038/s41467-020-14447-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 12/17/2019] [Indexed: 11/09/2022] Open
Abstract
Extreme slip at shallow depths on subduction zone faults is a primary contributor to tsunami generation by earthquakes. Improving earthquake and tsunami risk assessment requires understanding the material and structural conditions that favor earthquake propagation to the trench. We use new biomarker thermal maturity indicators to identify seismic faults in drill core recovered from the Japan Trench subduction zone, which hosted 50 m of shallow slip during the Mw9.1 2011 Tohoku-Oki earthquake. Our results show that multiple faults have hosted earthquakes with displacement ≥ 10 m, and each could have hosted many great earthquakes, illustrating an extensive history of great earthquake seismicity that caused large shallow slip. We find that lithologic contrasts in frictional properties do not necessarily determine the likelihood of large shallow slip or seismic hazard.
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Affiliation(s)
- Hannah S Rabinowitz
- AAAS Science and Technology Policy Fellow at the U.S. Department of Energy, 955 L'Enfant Plaza SW, Washington, DC, 20024, USA.
| | - Heather M Savage
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, 1156 High St, Santa Cruz, CA, 95064, USA
| | - Pratigya J Polissar
- Department of Ocean Sciences, University of California, Santa Cruz, 1156 High St., Santa Cruz, CA, 95064, USA
| | - Christie D Rowe
- Department of Earth and Planetary Sciences, McGill University, 3450 University St, Montreal, QC, H3A 0E8, Canada
| | - James D Kirkpatrick
- Department of Earth and Planetary Sciences, McGill University, 3450 University St, Montreal, QC, H3A 0E8, Canada
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26
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Upper-plate rigidity determines depth-varying rupture behaviour of megathrust earthquakes. Nature 2019; 576:96-101. [PMID: 31776513 DOI: 10.1038/s41586-019-1784-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/20/2019] [Indexed: 11/09/2022]
Abstract
Seismological data provide evidence of a depth-dependent rupture behaviour of earthquakes occurring at the megathrust fault of subduction zones, also known as megathrust earthquakes1. Relative to deeper events of similar magnitude, shallow earthquake ruptures have larger slip and longer duration, radiate energy that is depleted in high frequencies and have a larger discrepancy between their surface-wave and moment magnitudes1-3. These source properties make them prone to generating devastating tsunamis without clear warning signs. The depth-dependent rupture behaviour is usually attributed to variations in fault mechanics4-7. Conceptual models, however, have so far failed to identify the fundamental physical causes of the contrasting observations and do not provide a quantitative framework with which to predict and link them. Here we demonstrate that the observed differences do not require changes in fault mechanics. We use compressional-wave velocity models from worldwide subduction zones to show that their common underlying cause is a systematic depth variation of the rigidity at the lower part of the upper plate - the rock body overriding the megathrust fault, which deforms by dynamic stress transfer during co-seismic slip. Combining realistic elastic properties with accurate estimates of earthquake focal depth enables us to predict the amount of co-seismic slip (the fault motion at the instant of the earthquake), provides unambiguous estimations of magnitude and offers the potential for early tsunami warnings.
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27
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Diederichs A, Nissen EK, Lajoie LJ, Langridge RM, Malireddi SR, Clark KJ, Hamling IJ, Tagliasacchi A. Unusual kinematics of the Papatea fault (2016 Kaikōura earthquake) suggest anelastic rupture. SCIENCE ADVANCES 2019; 5:eaax5703. [PMID: 31616791 PMCID: PMC6774718 DOI: 10.1126/sciadv.aax5703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 09/08/2019] [Indexed: 05/21/2023]
Abstract
A key paradigm in seismology is that earthquakes release elastic strain energy accumulated during an interseismic period on approximately planar faults. Earthquake slip models may be further informed by empirical relations such as slip to length. Here, we use differential lidar to demonstrate that the Papatea fault-a key element within the 2016 Mw 7.8 Kaikōura earthquake rupture-has a distinctly nonplanar geometry, far exceeded typical coseismic slip-to-length ratios, and defied Andersonian mechanics by slipping vertically at steep angles. Additionally, its surface deformation is poorly reproduced by elastic dislocation models, suggesting the Papatea fault did not release stored strain energy as typically assumed, perhaps explaining its seismic quiescence in back-projections. Instead, it slipped in response to neighboring fault movements, creating a localized space problem, accounting for its anelastic deformation field. Thus, modeling complex, multiple-fault earthquakes as slip on planar faults embedded in an elastic medium may not always be appropriate.
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Affiliation(s)
- A. Diederichs
- School of Earth and Ocean Sciences, University of Victoria, Victoria, BC, Canada
- Corresponding author.
| | - E. K. Nissen
- School of Earth and Ocean Sciences, University of Victoria, Victoria, BC, Canada
| | - L. J. Lajoie
- Department of Geophysics, Colorado School of Mines, 1500 Illinois St., Golden, CO, USA
| | | | - S. R. Malireddi
- Department of Computer Sciences, University of Victoria, Victoria, BC, Canada
| | - K. J. Clark
- GNS Science, PO Box 30 368, Lower Hutt 5040, New Zealand
| | - I. J. Hamling
- GNS Science, PO Box 30 368, Lower Hutt 5040, New Zealand
| | - A. Tagliasacchi
- Department of Computer Sciences, University of Victoria, Victoria, BC, Canada
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28
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Hirono T, Tsuda K, Kaneki S. Role of Weak Materials in Earthquake Rupture Dynamics. Sci Rep 2019; 9:6604. [PMID: 31036864 PMCID: PMC6488621 DOI: 10.1038/s41598-019-43118-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/17/2019] [Indexed: 12/03/2022] Open
Abstract
Weak materials in seismic slip zones are important in studies of earthquake mechanics. For instance, the exceptionally large slip during the 2011 Tohoku-Oki earthquake has been attributed to the presence of smectite in the fault zone. However, weak fault rocks cannot accumulate large amounts of elastic strain, which is thought to counter their ability to enhance seismic rupture. It is well known that if the permeability of a weak fault is low enough to allow friction-induced thermal pressurization of interstitial fluid, the fault strength decreases dramatically. However, whether intrinsic weakness of fault material or thermal pressurization more efficiently produces large slip on faults bearing weak materials has not been determined. To investigate the role of weak materials in earthquake rupture dynamics, we conducted friction experiments and dynamic rupture simulations using pure smectite and pure graphite to represent weak fault materials. Even when we assumed no thermal pressurization, simulated faults in both media were able to trigger large slip because their extremely low friction was insufficient to arrest the inertial motion of rupture propagating along the fault. We used similar rupture simulations to investigate the cause of the huge slip near the trench during the 2011 Tohoku-Oki earthquake and demonstrated that it can be attributed to thermal pressurization, although our findings suggest that the presence of smectite in the plate-boundary fault may also be required.
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Affiliation(s)
- Tetsuro Hirono
- Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.
| | - Kenichi Tsuda
- Center for Safety and Reliability Engineering, Institute of Technology, Shimizu Corporation, Koto, Tokyo, 135-8530, Japan
| | - Shunya Kaneki
- Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.,Disaster Prevention Research Institute, Kyoto University, Uji, Kyoto, 611-0011, Japan
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29
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Dynamic earthquake rupture preserved in a creeping serpentinite shear zone. Nat Commun 2018; 9:3552. [PMID: 30177707 PMCID: PMC6120932 DOI: 10.1038/s41467-018-05965-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 08/06/2018] [Indexed: 11/24/2022] Open
Abstract
Laboratory experiments on serpentinite suggest that extreme dynamic weakening at earthquake slip rates is accompanied by amorphisation, dehydration and possible melting. However, hypotheses arising from experiments remain untested in nature, because earthquake ruptures have not previously been recognised in serpentinite shear zones. Here we document the progressive formation of high-temperature reaction products that formed by coseismic amorphisation and dehydration in a plate boundary-scale serpentinite shear zone. The highest-temperature products are aggregates of nanocrystalline olivine and enstatite, indicating minimum peak coseismic temperatures of ca. 925 ± 60 °C. Modelling suggests that frictional heating during earthquakes of magnitude 2.7–4 can satisfy the petrological constraints on the coseismic temperature profile, assuming that coseismic fluid storage capacity and permeability are increased by the development of reaction-enhanced porosity. Our results indicate that earthquake ruptures can propagate through serpentinite shear zones, and that the signatures of transient frictional heating can be preserved in the fault rock record. Creeping serpentinite shear zones may host large earthquakes, but direct evidence of frictional heating and rupture have been missing. Here, the authors demonstrate via laboratory experiments that earthquake ruptures can propagate through serpentinite shear zones shown by high-temperature reaction products.
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30
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Liu X, Zhao D. Upper and lower plate controls on the great 2011 Tohoku-oki earthquake. SCIENCE ADVANCES 2018; 4:eaat4396. [PMID: 29938226 PMCID: PMC6010320 DOI: 10.1126/sciadv.aat4396] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/15/2018] [Indexed: 06/08/2023]
Abstract
The great 2011 Tohoku-oki earthquake [moment magnitude (Mw) 9.0)] is the best-documented megathrust earthquake in the world, but its causal mechanism is still in controversy because of the poor state of knowledge on the nature of the megathrust zone. We constrain the structure of the Tohoku forearc using seismic tomography, residual topography, and gravity data, which reveal a close relationship between structural heterogeneities in and around the megathrust zone and rupture processes of the 2011 Tohoku-oki earthquake. Its mainshock nucleated in an area with high seismic velocity, low seismic attenuation, and strong seismic coupling, probably indicating a large asperity (or a cluster of asperities) in the megathrust zone. Strong coseismic high-frequency radiations also occurred in high-velocity patches, whereas large afterslips took plate in low-velocity areas, differences that may reflect changes in fault friction and lithological variations. These structural heterogeneities in and around the Tohoku megathrust originate from both the overriding and subducting plates, which controlled the nucleation and rupture processes of the 2011 Tohoku-oki earthquake.
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Affiliation(s)
- Xin Liu
- Department of Geophysics, Tohoku University, Sendai 980-8578, Japan
- Key Lab of Submarine Geosciences and Prospecting Techniques, Ministry of Education, and College of Marine Geosciences, Ocean University of China, Qingdao 266100, China
| | - Dapeng Zhao
- Department of Geophysics, Tohoku University, Sendai 980-8578, Japan
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Rolandone F, Nocquet JM, Mothes PA, Jarrin P, Vallée M, Cubas N, Hernandez S, Plain M, Vaca S, Font Y. Areas prone to slow slip events impede earthquake rupture propagation and promote afterslip. SCIENCE ADVANCES 2018; 4:eaao6596. [PMID: 29404404 PMCID: PMC5796792 DOI: 10.1126/sciadv.aao6596] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 01/03/2018] [Indexed: 05/31/2023]
Abstract
At subduction zones, transient aseismic slip occurs either as afterslip following a large earthquake or as episodic slow slip events during the interseismic period. Afterslip and slow slip events are usually considered as distinct processes occurring on separate fault areas governed by different frictional properties. Continuous GPS (Global Positioning System) measurements following the 2016 Mw (moment magnitude) 7.8 Ecuador earthquake reveal that large and rapid afterslip developed at discrete areas of the megathrust that had previously hosted slow slip events. Regardless of whether they were locked or not before the earthquake, these areas appear to persistently release stress by aseismic slip throughout the earthquake cycle and outline the seismic rupture, an observation potentially leading to a better anticipation of future large earthquakes.
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Affiliation(s)
- Frederique Rolandone
- Sorbonne Université, CNRS-INSU, Institut des Sciences de la Terre Paris, ISTeP UMR 7193, F-75005 Paris, France
- Université Côte d’Azur, IRD, CNRS, Observatoire de la Côte d’Azur, Géoazur, Valbonne, France
| | - Jean-Mathieu Nocquet
- Université Côte d’Azur, IRD, CNRS, Observatoire de la Côte d’Azur, Géoazur, Valbonne, France
- Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154 CNRS, Paris, France
| | | | - Paul Jarrin
- Instituto Geofísico, Escuela Politécnica Nacional, Quito, Ecuador
| | - Martin Vallée
- Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154 CNRS, Paris, France
| | - Nadaya Cubas
- Sorbonne Université, CNRS-INSU, Institut des Sciences de la Terre Paris, ISTeP UMR 7193, F-75005 Paris, France
| | | | - Morgan Plain
- Instituto Geofísico, Escuela Politécnica Nacional, Quito, Ecuador
| | - Sandro Vaca
- Instituto Geofísico, Escuela Politécnica Nacional, Quito, Ecuador
| | - Yvonne Font
- Université Côte d’Azur, IRD, CNRS, Observatoire de la Côte d’Azur, Géoazur, Valbonne, France
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32
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Nielsen S. From slow to fast faulting: recent challenges in earthquake fault mechanics. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2016.0016. [PMID: 28827428 PMCID: PMC5580450 DOI: 10.1098/rsta.2016.0016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/03/2017] [Indexed: 06/07/2023]
Abstract
Faults-thin zones of highly localized shear deformation in the Earth-accommodate strain on a momentous range of dimensions (millimetres to hundreds of kilometres for major plate boundaries) and of time intervals (from fractions of seconds during earthquake slip, to years of slow, aseismic slip and millions of years of intermittent activity). Traditionally, brittle faults have been distinguished from shear zones which deform by crystal plasticity (e.g. mylonites). However such brittle/plastic distinction becomes blurred when considering (i) deep earthquakes that happen under conditions of pressure and temperature where minerals are clearly in the plastic deformation regime (a clue for seismologists over several decades) and (ii) the extreme dynamic stress drop occurring during seismic slip acceleration on faults, requiring efficient weakening mechanisms. High strain rates (more than 104 s-1) are accommodated within paper-thin layers (principal slip zone), where co-seismic frictional heating triggers non-brittle weakening mechanisms. In addition, (iii) pervasive off-fault damage is observed, introducing energy sinks which are not accounted for by traditional frictional models. These observations challenge our traditional understanding of friction (rate-and-state laws), anelastic deformation (creep and flow of crystalline materials) and the scientific consensus on fault operation.This article is part of the themed issue 'Faulting, friction and weakening: from slow to fast motion'.
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Affiliation(s)
- S Nielsen
- Department of Earth Sciences, Durham University, Durham DH1 5ED, UK
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Noda H, Sawai M, Shibazaki B. Earthquake sequence simulations with measured properties for JFAST core samples. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2016.0003. [PMID: 28827425 PMCID: PMC5580447 DOI: 10.1098/rsta.2016.0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/27/2017] [Indexed: 06/07/2023]
Abstract
Since the 2011 Tohoku-Oki earthquake, multi-disciplinary observational studies have promoted our understanding of both the coseismic and long-term behaviour of the Japan Trench subduction zone. We also have suggestions for mechanical properties of the fault from the experimental side. In the present study, numerical models of earthquake sequences are presented, accounting for the experimental outcomes and being consistent with observations of both long-term and coseismic fault behaviour and thermal measurements. Among the constraints, a previous study of friction experiments for samples collected in the Japan Trench Fast Drilling Project (JFAST) showed complex rate dependences: a and a-b values change with the slip rate. In order to express such complexity, we generalize a rate- and state-dependent friction law to a quadratic form in terms of the logarithmic slip rate. The constraints from experiments reduced the degrees of freedom of the model significantly, and we managed to find a plausible model by changing only a few parameters. Although potential scale effects between lab experiments and natural faults are important problems, experimental data may be useful as a guide in exploring the huge model parameter space.This article is part of the themed issue 'Faulting, friction and weakening: from slow to fast motion'.
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Affiliation(s)
- Hiroyuki Noda
- Disaster Prevention Research Institute, Kyoto University, Uji, 611-0002, Japan
| | - Michiyo Sawai
- Department of Earth Sciences, Chiba University, Chiba, 263-8522, Japan
| | - Bunichiro Shibazaki
- International Institute of Seismology and Earthquake Engineering, Building Research Institute, Tsukuba, 305-0802, Japan
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Rice JR. Heating, weakening and shear localization in earthquake rupture. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2016.0015. [PMID: 28827427 PMCID: PMC5580449 DOI: 10.1098/rsta.2016.0015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/03/2017] [Indexed: 06/07/2023]
Abstract
Field and borehole observations of active earthquake fault zones show that shear is often localized to principal deforming zones of order 0.1-10 mm width. This paper addresses how frictional heating in rapid slip weakens faults dramatically, relative to their static frictional strength, and promotes such intense localization. Pronounced weakening occurs even on dry rock-on-rock surfaces, due to flash heating effects, at slip rates above approximately 0.1 m s-1 (earthquake slip rates are typically of the order of 1 m s-1). But weakening in rapid shear is also predicted theoretically in thick fault gouge in the presence of fluids (whether native ground fluids or volatiles such as H2O or CO2 released by thermal decomposition reactions), and the predicted localizations are compatible with such narrow shear zones as have been observed. The underlying concepts show how fault zone materials with high static friction coefficients, approximately 0.6-0.8, can undergo strongly localized shear at effective dynamic friction coefficients of the order of 0.1, thus fitting observational constraints, e.g. of earthquakes producing negligible surface heat outflow and, for shallow events, only rarely creating extensive melt. The results to be summarized include those of collaborative research published with Nicolas Brantut (University College London), Eric Dunham (Stanford University), Nadia Lapusta (Caltech), Hiroyuki Noda (JAMSTEC, Japan), John D. Platt (Carnegie Institution for Science, now at *gramLabs), Alan Rempel (Oregon State University) and John W. Rudnicki (Northwestern University).This article is part of the themed issue 'Faulting, friction and weakening: from slow to fast motion'.
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Affiliation(s)
- James R Rice
- School of Engineering and Applied Science, Harvard University, Cambridge, MA, USA
- Department of Earth and Planetary Science, Harvard University, Cambridge, MA, USA
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35
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Understanding dynamic friction through spontaneously evolving laboratory earthquakes. Nat Commun 2017; 8:15991. [PMID: 28660876 PMCID: PMC5493769 DOI: 10.1038/ncomms15991] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 05/18/2017] [Indexed: 11/08/2022] Open
Abstract
Friction plays a key role in how ruptures unzip faults in the Earth's crust and release waves that cause destructive shaking. Yet dynamic friction evolution is one of the biggest uncertainties in earthquake science. Here we report on novel measurements of evolving local friction during spontaneously developing mini-earthquakes in the laboratory, enabled by our ultrahigh speed full-field imaging technique. The technique captures the evolution of displacements, velocities and stresses of dynamic ruptures, whose rupture speed range from sub-Rayleigh to supershear. The observed friction has complex evolution, featuring initial velocity strengthening followed by substantial velocity weakening. Our measurements are consistent with rate-and-state friction formulations supplemented with flash heating but not with widely used slip-weakening friction laws. This study develops a new approach for measuring local evolution of dynamic friction and has important implications for understanding earthquake hazard since laws governing frictional resistance of faults are vital ingredients in physically-based predictive models of the earthquake source.
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36
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Passelègue FX, Latour S, Schubnel A, Nielsen S, Bhat HS, Madariaga R. Influence of Fault Strength on Precursory Processes During Laboratory Earthquakes. FAULT ZONE DYNAMIC PROCESSES 2017. [DOI: 10.1002/9781119156895.ch12] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Affiliation(s)
- François. X. Passelègue
- Laboratoire de Géologie; CNRS, École Normale Supérieure; Paris France
- University of Manchester; Manchester UK
| | - Soumaya Latour
- Laboratoire de Géologie; CNRS, École Normale Supérieure; Paris France
| | | | | | | | - Raúl Madariaga
- Laboratoire de Géologie; CNRS, École Normale Supérieure; Paris France
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McCarthy C, Savage H, Nettles M. Temperature dependence of ice-on-rock friction at realistic glacier conditions. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:20150348. [PMID: 28025297 PMCID: PMC5179958 DOI: 10.1098/rsta.2015.0348] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/17/2016] [Indexed: 06/06/2023]
Abstract
Using a new biaxial friction apparatus, we conducted experiments of ice-on-rock friction in order to better understand basal sliding of glaciers and ice streams. A series of velocity-stepping and slide-hold-slide tests were conducted to measure friction and healing at temperatures between -20°C and melting. Experimental conditions in this study are comparable to subglacial temperatures, sliding rates and effective pressures of Antarctic ice streams and other glaciers, with load-point velocities ranging from 0.5 to 100 µm s-1 and normal stress σn = 100 kPa. In this range of conditions, temperature dependences of both steady-state friction and frictional healing are considerable. The friction increases linearly with decreasing temperature (temperature weakening) from μ = 0.52 at -20°C to μ = 0.02 at melting. Frictional healing increases and velocity dependence shifts from velocity-strengthening to velocity-weakening behaviour with decreasing temperature. Our results indicate that the strength and stability of glaciers and ice streams may change considerably over the range of temperatures typically found at the ice-bed interface.This article is part of the themed issue 'Microdynamics of ice'.
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Affiliation(s)
- C McCarthy
- Lamont-Doherty Earth Observatory, Columbia University, New York, NY, USA
| | - H Savage
- Lamont-Doherty Earth Observatory, Columbia University, New York, NY, USA
| | - M Nettles
- Lamont-Doherty Earth Observatory, Columbia University, New York, NY, USA
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38
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Sun T, Wang K, Fujiwara T, Kodaira S, He J. Large fault slip peaking at trench in the 2011 Tohoku-oki earthquake. Nat Commun 2017; 8:14044. [PMID: 28074829 PMCID: PMC5241695 DOI: 10.1038/ncomms14044] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 11/22/2016] [Indexed: 11/09/2022] Open
Abstract
During the 2011 magnitude 9 Tohoku-oki earthquake, very large slip occurred on the shallowest part of the subduction megathrust. Quantitative information on the shallow slip is of critical importance to distinguishing between different rupture mechanics and understanding the generation of the ensuing devastating tsunami. However, the magnitude and distribution of the shallow slip are essentially unknown due primarily to the lack of near-trench constraints, as demonstrated by a compilation of 45 rupture models derived from a large range of data sets. To quantify the shallow slip, here we model high-resolution bathymetry differences before and after the earthquake across the trench axis. The slip is determined to be about 62 m over the most near-trench 40 km of the fault with a gentle increase towards the trench. This slip distribution indicates that dramatic net weakening or strengthening of the shallow fault did not occur during the Tohoku-oki earthquake. The 2011 Tohoku-oki earthquake slip occurred on the shallowest part of the megathrust, but the nature of the shallow slip has been poorly constrained. Here, the authors model bathymetry differences before and after the earthquake to determine that the slip exceeded 60 m increasing towards the trench.
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Affiliation(s)
- Tianhaozhe Sun
- School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada V8P 5C2
| | - Kelin Wang
- School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada V8P 5C2.,Pacific Geoscience Centre, Geological Survey of Canada, Natural Resources Canada, 9860 West Saanich Road, Sidney, British Columbia, Canada V8L 4B2
| | - Toshiya Fujiwara
- R&D Center for Earthquake and Tsunami (CEAT), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushima-cho 2-15, Yokosuka 237-0061, Japan
| | - Shuichi Kodaira
- R&D CEAT, JAMSTEC, Showa-machi 3173-25, Kanazawa-ku, Yokohama 236-0001, Japan
| | - Jiangheng He
- Pacific Geoscience Centre, Geological Survey of Canada, Natural Resources Canada, 9860 West Saanich Road, Sidney, British Columbia, Canada V8L 4B2
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39
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Watt J, Ponce D, Parsons T, Hart P. Missing link between the Hayward and Rodgers Creek faults. SCIENCE ADVANCES 2016; 2:e1601441. [PMID: 27774514 PMCID: PMC5072180 DOI: 10.1126/sciadv.1601441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/22/2016] [Indexed: 06/06/2023]
Abstract
The next major earthquake to strike the ~7 million residents of the San Francisco Bay Area will most likely result from rupture of the Hayward or Rodgers Creek faults. Until now, the relationship between these two faults beneath San Pablo Bay has been a mystery. Detailed subsurface imaging provides definitive evidence of active faulting along the Hayward fault as it traverses San Pablo Bay and bends ~10° to the right toward the Rodgers Creek fault. Integrated geophysical interpretation and kinematic modeling show that the Hayward and Rodgers Creek faults are directly connected at the surface-a geometric relationship that has significant implications for earthquake dynamics and seismic hazard. A direct link enables simultaneous rupture of the Hayward and Rodgers Creek faults, a scenario that could result in a major earthquake (M = 7.4) that would cause extensive damage and loss of life with global economic impact.
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Affiliation(s)
- Janet Watt
- U.S. Geological Survey, Santa Cruz, CA 95060, USA
| | - David Ponce
- U.S. Geological Survey, Menlo Park, CA 94025, USA
| | - Tom Parsons
- U.S. Geological Survey, Menlo Park, CA 94025, USA
| | - Patrick Hart
- U.S. Geological Survey, Santa Cruz, CA 95060, USA
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40
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Jiang J, Lapusta N. Deeper penetration of large earthquakes on seismically quiescent faults. Science 2016; 352:1293-7. [PMID: 27284188 DOI: 10.1126/science.aaf1496] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 05/11/2016] [Indexed: 11/03/2022]
Abstract
Why many major strike-slip faults known to have had large earthquakes are silent in the interseismic period is a long-standing enigma. One would expect small earthquakes to occur at least at the bottom of the seismogenic zone, where deeper aseismic deformation concentrates loading. We suggest that the absence of such concentrated microseismicity indicates deep rupture past the seismogenic zone in previous large earthquakes. We support this conclusion with numerical simulations of fault behavior and observations of recent major events. Our modeling implies that the 1857 Fort Tejon earthquake on the San Andreas Fault in Southern California penetrated below the seismogenic zone by at least 3 to 5 kilometers. Our findings suggest that such deeper ruptures may occur on other major fault segments, potentially increasing the associated seismic hazard.
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Affiliation(s)
- Junle Jiang
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Nadia Lapusta
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA. Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena, CA, USA.
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41
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Spagnuolo E, Nielsen S, Violay M, Di Toro G. An empirically based steady state friction law and implications for fault stability. GEOPHYSICAL RESEARCH LETTERS 2016; 43:3263-3271. [PMID: 27667875 PMCID: PMC5021208 DOI: 10.1002/2016gl067881] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/23/2016] [Accepted: 03/24/2016] [Indexed: 06/06/2023]
Abstract
Empirically based rate-and-state friction laws (RSFLs) have been proposed to model the dependence of friction forces with slip and time. The relevance of the RSFL for earthquake mechanics is that few constitutive parameters define critical conditions for fault stability (i.e., critical stiffness and frictional fault behavior). However, the RSFLs were determined from experiments conducted at subseismic slip rates (V < 1 cm/s), and their extrapolation to earthquake deformation conditions (V > 0.1 m/s) remains questionable on the basis of the experimental evidence of (1) large dynamic weakening and (2) activation of particular fault lubrication processes at seismic slip rates. Here we propose a modified RSFL (MFL) based on the review of a large published and unpublished data set of rock friction experiments performed with different testing machines. The MFL, valid at steady state conditions from subseismic to seismic slip rates (0.1 µm/s < V < 3 m/s), describes the initiation of a substantial velocity weakening in the 1-20 cm/s range resulting in a critical stiffness increase that creates a peak of potential instability in that velocity regime. The MFL leads to a new definition of fault frictional stability with implications for slip event styles and relevance for models of seismic rupture nucleation, propagation, and arrest.
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Affiliation(s)
- E. Spagnuolo
- Istituto Nazionale di Geofisica e VulcanologiaRomeItaly
| | - S. Nielsen
- Department of Earth SciencesUniversity of DurhamDurhamUK
| | - M. Violay
- LEMR, ENAC, École polytechnique fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - G. Di Toro
- Istituto Nazionale di Geofisica e VulcanologiaRomeItaly
- School of Earth, Atmospheric and Environmental SciencesUniversity of ManchesterManchesterUK
- Dipartimento di GeoscienzeUniversità degli Studi di PadovaPaduaItaly
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42
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Veedu DM, Barbot S. The Parkfield tremors reveal slow and fast ruptures on the same asperity. Nature 2016; 532:361-5. [DOI: 10.1038/nature17190] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 01/26/2016] [Indexed: 11/09/2022]
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Guglielmi Y, Cappa F, Avouac JP, Henry P, Elsworth D. INDUCED SEISMICITY. Seismicity triggered by fluid injection-induced aseismic slip. Science 2015; 348:1224-6. [PMID: 26068845 DOI: 10.1126/science.aab0476] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/09/2015] [Indexed: 11/02/2022]
Abstract
Anthropogenic fluid injections are known to induce earthquakes. The mechanisms involved are poorly understood, and our ability to assess the seismic hazard associated with geothermal energy or unconventional hydrocarbon production remains limited. We directly measure fault slip and seismicity induced by fluid injection into a natural fault. We observe highly dilatant and slow [~4 micrometers per second (μm/s)] aseismic slip associated with a 20-fold increase of permeability, which transitions to faster slip (~10 μm/s) associated with reduced dilatancy and micro-earthquakes. Most aseismic slip occurs within the fluid-pressurized zone and obeys a rate-strengthening friction law μ = 0.67 + 0.045ln(v/v₀) with v₀ = 0.1 μm/s. Fluid injection primarily triggers aseismic slip in this experiment, with micro-earthquakes being an indirect effect mediated by aseismic creep.
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Affiliation(s)
- Yves Guglielmi
- Centre de Recherche et d'Enseignement de Géosciences de l'Environnement (UMR7330), University of Aix-Marseille, CNRS, IRD, 13545 Aix-en-Provence, France.
| | - Frédéric Cappa
- Géoazur (UMR 7329), University of Nice Sophia-Antipolis, CNRS, IRD, Côte d'Azur Observatory, 06560 Sophia-Antipolis, France. Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jean-Philippe Avouac
- Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Pierre Henry
- Centre de Recherche et d'Enseignement de Géosciences de l'Environnement (UMR7330), University of Aix-Marseille, CNRS, IRD, 13545 Aix-en-Provence, France
| | - Derek Elsworth
- Energy and Mineral Engineering and Geosciences, Earth and Mineral Sciences Energy Institute and G3 Center, Pennsylvania State University, University Park, PA 16802, USA
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Schurr B, Asch G, Hainzl S, Bedford J, Hoechner A, Palo M, Wang R, Moreno M, Bartsch M, Zhang Y, Oncken O, Tilmann F, Dahm T, Victor P, Barrientos S, Vilotte JP. Gradual unlocking of plate boundary controlled initiation of the 2014 Iquique earthquake. Nature 2014; 512:299-302. [PMID: 25119049 DOI: 10.1038/nature13681] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/14/2014] [Indexed: 11/09/2022]
Abstract
On 1 April 2014, Northern Chile was struck by a magnitude 8.1 earthquake following a protracted series of foreshocks. The Integrated Plate Boundary Observatory Chile monitored the entire sequence of events, providing unprecedented resolution of the build-up to the main event and its rupture evolution. Here we show that the Iquique earthquake broke a central fraction of the so-called northern Chile seismic gap, the last major segment of the South American plate boundary that had not ruptured in the past century. Since July 2013 three seismic clusters, each lasting a few weeks, hit this part of the plate boundary with earthquakes of increasing peak magnitudes. Starting with the second cluster, geodetic observations show surface displacements that can be associated with slip on the plate interface. These seismic clusters and their slip transients occupied a part of the plate interface that was transitional between a fully locked and a creeping portion. Leading up to this earthquake, the b value of the foreshocks gradually decreased during the years before the earthquake, reversing its trend a few days before the Iquique earthquake. The mainshock finally nucleated at the northern end of the foreshock area, which skirted a locked patch, and ruptured mainly downdip towards higher locking. Peak slip was attained immediately downdip of the foreshock region and at the margin of the locked patch. We conclude that gradual weakening of the central part of the seismic gap accentuated by the foreshock activity in a zone of intermediate seismic coupling was instrumental in causing final failure, distinguishing the Iquique earthquake from most great earthquakes. Finally, only one-third of the gap was broken and the remaining locked segments now pose a significant, increased seismic hazard with the potential to host an earthquake with a magnitude of >8.5.
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Affiliation(s)
- Bernd Schurr
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Günter Asch
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Sebastian Hainzl
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Jonathan Bedford
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Andreas Hoechner
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Mauro Palo
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Rongjiang Wang
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Marcos Moreno
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Mitja Bartsch
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Yong Zhang
- School of Earth and Space Sciences, Peking University, Beijing 100871, China
| | - Onno Oncken
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Frederik Tilmann
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Torsten Dahm
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Pia Victor
- GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Sergio Barrientos
- Centro Sismológico National, Universidad de Chile, Facultad de Ciencias Físicas y Matemáticas, Blanco Encalada 2002, Santiago, Chile
| | - Jean-Pierre Vilotte
- Institut de Physique du Globe de Paris, 1, rue Jussieu, 75238 Paris cedex 05, France
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45
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Structural control on the Tohoku earthquake rupture process investigated by 3D FEM, tsunami and geodetic data. Sci Rep 2014; 4:5631. [PMID: 25005351 PMCID: PMC4087921 DOI: 10.1038/srep05631] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 06/20/2014] [Indexed: 11/08/2022] Open
Abstract
The 2011 Tohoku earthquake (Mw = 9.1) highlighted previously unobserved features for megathrust events, such as the large slip in a relatively limited area and the shallow rupture propagation. We use a Finite Element Model (FEM), taking into account the 3D geometrical and structural complexities up to the trench zone, and perform a joint inversion of tsunami and geodetic data to retrieve the earthquake slip distribution. We obtain a close spatial correlation between the main deep slip patch and the local seismic velocity anomalies, and large shallow slip extending also to the North coherently with a seismically observed low-frequency radiation. These observations suggest that the friction controlled the rupture, initially confining the deeper rupture and then driving its propagation up to the trench, where it spreads laterally. These findings are relevant to earthquake and tsunami hazard assessment because they may help to detect regions likely prone to rupture along the megathrust, and to constrain the probability of high slip near the trench. Our estimate of ~40 m slip value around the JFAST (Japan Trench Fast Drilling Project) drilling zone contributes to constrain the dynamic shear stress and friction coefficient of the fault obtained by temperature measurements to ~0.68 MPa and ~0.10, respectively.
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Earth science: Fertile fields for seismicity. Nature 2014; 509:436-7. [PMID: 24828039 DOI: 10.1038/nature13338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Affiliation(s)
- Kelin Wang
- Pacific Geoscience Centre, Geological Survey of Canada, Natural Resources Canada, Sidney, British Columbia, Canada V8L 4B2
| | - Masataka Kinoshita
- Kochi Institute for Core Sample Research, JAMSTEC, Nankoku, Kochi, 783-8502 Japan
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Jones N. Killer qualities of Japanese fault revealed. Nature 2013. [DOI: 10.1038/nature.2013.14316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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