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Rheology of the Northern Tibetan Plateau Lithosphere Inferred from the Post-Seismic Deformation Resulting from the 2001 Mw 7.8 Kokoxili Earthquake. REMOTE SENSING 2022. [DOI: 10.3390/rs14051207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Time-series observations from Sentinel-1 A/B InSAR spanning November 2014 to July 2021 were used to study the late post-seismic deformation velocity field arising from the Kokoxili earthquake. The deformation velocity caused by the interseismic slip along the major active faults in Tibet was first simulated. Comparing the simulated deformation velocity with the observed one, the maximum ratio of the simulated deformation velocity to the observed one was found to be 42%, indicating continuity in the viscoelastic relaxation caused by the 2001 Kokoxili earthquake. Subsequently, the rheological structure of the Kokoxili region was explored using a mixed model comprising the viscoelastic relaxation mechanism and the buried elastic dislocation model. The best estimated viscosities for the lower crust and upper mantle were ηlc=1−0.44+0.78×1019 Pas and ηum=1+0+0.78×1020 Pas, respectively. The results obtained in this study were compared with those of previous studies that used the early post-seismic displacement ranging from 0 to 6.5 years following the earthquake. The obtained value was largely the same as the previously estimated steady-state viscosity, which means that the viscosities of the viscoelastic layer beneath the Kokoxili regions have almost reached their stable state. Furthermore, the effective lower crustal viscosity of the Kokoxili region exhibited a logarithmic trend with time.
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2
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Granat R, Donnellan A, Heflin M, Lyzenga G, Glasscoe M, Parker J, Pierce M, Wang J, Rundle J, Ludwig LG. Clustering Analysis Methods for GNSS Observations: A Data-Driven Approach to Identifying California's Major Faults. EARTH AND SPACE SCIENCE (HOBOKEN, N.J.) 2021; 8:e2021EA001680. [PMID: 34820480 PMCID: PMC8596415 DOI: 10.1029/2021ea001680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 06/13/2023]
Abstract
We present a data-driven approach to clustering or grouping Global Navigation Satellite System (GNSS) stations according to observed velocities, displacements or other selected characteristics. Clustering GNSS stations provides useful scientific information, and is a necessary initial step in other analysis, such as detecting aseismic transient signals (Granat et al., 2013, https://doi.org/10.1785/0220130039). Desired features of the data can be selected for clustering, including some subset of displacement or velocity components, uncertainty estimates, station location, and other relevant information. Based on those selections, the clustering procedure autonomously groups the GNSS stations according to a selected clustering method. We have implemented this approach as a Python application, allowing us to draw upon the full range of open source clustering methods available in Python's scikit-learn package (Pedregosa et al., 2011, https://doi.org/10.5555/1953048.2078195). The application returns the stations labeled by group as a table and color coded KML file and is designed to work with the GNSS information available from GeoGateway (Donnellan et al., 2021, https://doi.org/10.1007/s12145-020-00561-7; Heflin et al., 2020, https://doi.org/10.1029/2019ea000644) but is easily extensible. We demonstrate the methodology on California and western Nevada. The results show partitions that follow faults or geologic boundaries, including for recent large earthquakes and post-seismic motion. The San Andreas fault system is most prominent, reflecting Pacific-North American plate boundary motion. Deformation reflected as class boundaries is distributed north and south of the central California creeping section. For most models a cluster boundary connects the southernmost San Andreas fault with the Eastern California Shear Zone (ECSZ) rather than continuing through the San Gorgonio Pass.
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Affiliation(s)
| | - Andrea Donnellan
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Michael Heflin
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Gregory Lyzenga
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Margaret Glasscoe
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Jay Parker
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | | | - Jun Wang
- Indiana UniversityBloomingtonINUSA
| | - John Rundle
- University of California, DavisThe Santa Fe InstituteSanta FeNMUSA
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Mandler E, Pintori F, Gualandi A, Anderlini L, Serpelloni E, Belardinelli ME. Post-Seismic Deformation Related to the 2016 Central Italy Seismic Sequence From GPS Displacement Time-Series. JOURNAL OF GEOPHYSICAL RESEARCH. SOLID EARTH 2021; 126:e2021JB022200. [PMID: 35845177 PMCID: PMC9285078 DOI: 10.1029/2021jb022200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/30/2021] [Accepted: 08/04/2021] [Indexed: 06/15/2023]
Abstract
The 2016-2017 Central Italy earthquake sequence struck the central Apennines between August 2016 and October 2016 with Mw ∈ [5.9; 6.5], plus four earthquakes occurring in January 2017 with Mw ∈ [5.0; 5.5]. We study Global Positioning System time series including near- and far-field domains. We use a variational Bayesian independent component analysis technique to separate the post-seismic deformation from signals caused by variation of the water content in aquifers at hundreds of meters of depth and of the soil moisture. For each independent component, realistic uncertainties and a plausible physical explanation are provided. We focus on the study of afterslip on the main structures surrounding the mainshock, highlighting the role played by faults that were not activated during the co-seismic phase in accommodating the post-seismic deformation. We report aseismic deformation occurring on the Paganica fault, which hosted the Mw 6.1 2009 L'Aquila earthquake, suggesting that static stress transfer and aseismic slip influence the recurrence time of nearby (∼50 km further south of the mainshocks) segments. A ∼2-3 km thick subhorizontal shear-zone, clearly illuminated by seismicity, which bounds at depth the west-dipping normal faults where the mainshocks nucleated, also shows aseismic slip. Since afterslip alone underestimates the displacement in the far-field domain, we consider the possibility that the shear zone marks the brittle-ductile transition, assuming the viscoelastic relaxation of the lower crust as a mechanism contributing to the post-seismic displacement. Our results suggest that multiple deformation processes are active in the first 2 years after the mainshocks.
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Affiliation(s)
- E. Mandler
- Dipartimento di Fisica e Astronomia “Augusto Righi”Alma Mater Studiorum Università di BolognaBolognaItaly
| | - F. Pintori
- Istituto Nazionaledi Geofisica e Vulcanologia (INGV)Osservatorio Nazionale TerremotiRomaItaly
| | - A. Gualandi
- Istituto Nazionaledi Geofisica e Vulcanologia (INGV)Osservatorio Nazionale TerremotiRomaItaly
| | - L. Anderlini
- Istituto Nazionale di Geofisica e Vulcanologia (INGV)Sezione di BolognaBolognaItaly
| | - E. Serpelloni
- Istituto Nazionaledi Geofisica e Vulcanologia (INGV)Osservatorio Nazionale TerremotiRomaItaly
- Istituto Nazionale di Geofisica e Vulcanologia (INGV)Sezione di BolognaBolognaItaly
| | - M. E. Belardinelli
- Dipartimento di Fisica e Astronomia “Augusto Righi”Alma Mater Studiorum Università di BolognaBolognaItaly
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Barbot S. Mantle flow distribution beneath the California margin. Nat Commun 2020; 11:4456. [PMID: 32901037 PMCID: PMC7479605 DOI: 10.1038/s41467-020-18260-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 08/13/2020] [Indexed: 11/09/2022] Open
Abstract
Although the surface deformation of tectonic plate boundaries is well determined by geological and geodetic measurements, the pattern of flow below the lithosphere remains poorly constrained. We use the crustal velocity field of the Plate Boundary Observatory to illuminate the distribution of horizontal flow beneath the California margin. At lower-crustal and upper-mantle depths, the boundary between the Pacific and North American plates is off-centered from the San Andreas fault, concentrated in a region that encompasses the trace of nearby active faults. A major step is associated with return flow below the Eastern California Shear Zone, leading to the extrusion of the Mojave block and a re-distribution of fault activity since the Pleistocene. Major earthquakes in California have occurred above the regions of current plastic strain accumulation. Deformation is mechanically coupled from the crust to the asthenosphere, with mantle flow overlaid by a kinematically consistent network of faults in the brittle crust.
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Affiliation(s)
- Sylvain Barbot
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, 90089-0740, USA.
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Rheology of the Zagros Lithosphere from Post-Seismic Deformation of the 2017 Mw7.3 Kermanshah, Iraq, Earthquake. REMOTE SENSING 2020. [DOI: 10.3390/rs12122032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We use 2018–2020 Sentinel-1 InSAR time series data to study post-seismic deformation processes following the 2017 Mw 7.3 Kermanshah, Iraq earthquake. We remove displacements caused by two large aftershock sequences from the displacement field. We find that for a six month period the response is dominated by afterslip along the up-dip extension of the coseismic rupture zone, producing up to 6 cm of radar line-of-sight displacements. The moment magnitude of afterslip is Mw 5.9 or 12% of the mainshock moment. After that period, the displacement field is best explained by viscoelastic relaxation and a lower crustal viscosity of η l c = 1 − 0.4 + 0.8 × 10 19 Pas . The viscosity of the uppermost mantle is not constrained by the data, except that it is larger than 0.6 × 10 19 Pas . The relatively high lower crustal and uppermost mantle viscosities are consistent with a cold and dry lithosphere of the Zagros region.
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Abstract
In the Basin and Range extensional province of the western United States, coseismic offsets, under the influence of gravity, display predominantly subsidence of the basin side (fault hanging wall), with comparatively little or no uplift of the mountainside (fault footwall). A few decades later, geodetic measurements [GPS and interferometric synthetic aperture radar (InSAR)] show broad (∼100 km) aseismic uplift symmetrically spanning the fault zone. Finally, after millions of years and hundreds of fault offsets, the mountain blocks display large uplift and tilting over a breadth of only about 10 km. These sparse but robust observations pose a problem in that the coesismic uplifts of the footwall are small and inadequate to raise the mountain blocks. To address this paradox we develop finite-element models subjected to extensional and gravitational forces to study time-varying deformation associated with normal faulting. Stretching the model under gravity demonstrates that asymmetric slip via collapse of the hanging wall is a natural consequence of coseismic deformation. Focused flow in the upper mantle imposed by deformation of the lower crust localizes uplift, which is predicted to take place within one to two decades after each large earthquake. Thus, the best-preserved topographic signature of earthquakes is expected to occur early in the postseismic period.
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Zhang X, Shcherbakov R. Power-law rheology controls aftershock triggering and decay. Sci Rep 2016; 6:36668. [PMID: 27819355 PMCID: PMC5098201 DOI: 10.1038/srep36668] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/18/2016] [Indexed: 11/17/2022] Open
Abstract
The occurrence of aftershocks is a signature of physical systems exhibiting relaxation phenomena. They are observed in various natural or experimental systems and usually obey several non-trivial empirical laws. Here we consider a cellular automaton realization of a nonlinear viscoelastic slider-block model in order to infer the physical mechanisms of triggering responsible for the occurrence of aftershocks. We show that nonlinear viscoelasticity plays a critical role in the occurrence of aftershocks. The model reproduces several empirical laws describing the statistics of aftershocks. In case of earthquakes, the proposed model suggests that the power-law rheology of the fault gauge, underlying lower crust, and upper mantle controls the decay rate of aftershocks. This is verified by analysing several prominent aftershock sequences for which the rheological properties of the underlying crust and upper mantle were established.
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Affiliation(s)
- Xiaoming Zhang
- Department of Earth Sciences, University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Robert Shcherbakov
- Department of Earth Sciences, University of Western Ontario, London, Ontario, N6A 5B7, Canada.,Department of Physics and Astronomy, University of Western Ontario, London, Ontario, N6A 3K7, Canada
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Bock Y, Melgar D. Physical applications of GPS geodesy: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:106801. [PMID: 27552205 DOI: 10.1088/0034-4885/79/10/106801] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Geodesy, the oldest science, has become an important discipline in the geosciences, in large part by enhancing Global Positioning System (GPS) capabilities over the last 35 years well beyond the satellite constellation's original design. The ability of GPS geodesy to estimate 3D positions with millimeter-level precision with respect to a global terrestrial reference frame has contributed to significant advances in geophysics, seismology, atmospheric science, hydrology, and natural hazard science. Monitoring the changes in the positions or trajectories of GPS instruments on the Earth's land and water surfaces, in the atmosphere, or in space, is important for both theory and applications, from an improved understanding of tectonic and magmatic processes to developing systems for mitigating the impact of natural hazards on society and the environment. Besides accurate positioning, all disturbances in the propagation of the transmitted GPS radio signals from satellite to receiver are mined for information, from troposphere and ionosphere delays for weather, climate, and natural hazard applications, to disturbances in the signals due to multipath reflections from the solid ground, water, and ice for environmental applications. We review the relevant concepts of geodetic theory, data analysis, and physical modeling for a myriad of processes at multiple spatial and temporal scales, and discuss the extensive global infrastructure that has been built to support GPS geodesy consisting of thousands of continuously operating stations. We also discuss the integration of heterogeneous and complementary data sets from geodesy, seismology, and geology, focusing on crustal deformation applications and early warning systems for natural hazards.
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Affiliation(s)
- Yehuda Bock
- Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, La Jolla, CA 92037, USA
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Time-Dependent Afterslip of the 2009 Mw 6.3 Dachaidan Earthquake (China) and Viscosity beneath the Qaidam Basin Inferred from Postseismic Deformation Observations. REMOTE SENSING 2016. [DOI: 10.3390/rs8080649] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Cavalié O, Vernotte F. Allan Variance Computed in Space Domain: Definition and Application to InSAR Data to Characterize Noise and Geophysical Signal. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2016; 63:590-610. [PMID: 26552083 DOI: 10.1109/tuffc.2015.2497002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The Allan variance was introduced 50 years ago for analyzing the stability of frequency standards. In addition to its metrological interest, it may be also considered as an estimator of the large trends of the power spectral density (PSD) of frequency deviation. For instance, the Allan variance is able to discriminate different types of noise characterized by different power laws in the PSD. The Allan variance was also used in other fields than time and frequency metrology: for more than 20 years, it has been used in accelerometry, geophysics, geodesy, astrophysics, and even finances. However, it seems that up to now, it has been exclusively applied for time series analysis. We propose here to use the Allan variance on spatial data. Interferometric synthetic aperture radar (InSAR) is used in geophysics to image ground displacements in space [over the synthetic aperture radar (SAR) image spatial coverage] and in time thanks to the regular SAR image acquisitions by dedicated satellites. The main limitation of the technique is the atmospheric disturbances that affect the radar signal while traveling from the sensor to the ground and back. In this paper, we propose to use the Allan variance for analyzing spatial data from InSAR measurements. The Allan variance was computed in XY mode as well as in radial mode for detecting different types of behavior for different space-scales, in the same way as the different types of noise versus the integration time in the classical time and frequency application. We found that radial Allan variance is the more appropriate way to have an estimator insensitive to the spatial axis and we applied it on SAR data acquired over eastern Turkey for the period 2003-2011. Spatial Allan variance allowed us to well characterize noise features, classically found in InSAR such as phase decorrelation producing white noise or atmospheric delays, behaving like a random walk signal. We finally applied the spatial Allan variance to an InSAR time series to detect when the geophysical signal, here the ground motion, emerges from the noise.
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11
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Shen ZK, King RW, Agnew DC, Wang M, Herring TA, Dong D, Fang P. A unified analysis of crustal motion in Southern California, 1970-2004: The SCEC crustal motion map. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jb008549] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Z.-K. Shen
- Department of Earth and Space Sciences; University of California; Los Angeles California USA
- School of Earth and Space Science; Peking University; Beijing China
| | - R. W. King
- Department of Earth, Atmospheric and Planetary Sciences; Massachusetts Institute of Technology; Cambridge Massachusetts USA
| | - D. C. Agnew
- Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography; University of California, San Diego; La Jolla California USA
| | - M. Wang
- Department of Earth and Space Sciences; University of California; Los Angeles California USA
| | - T. A. Herring
- Department of Earth, Atmospheric and Planetary Sciences; Massachusetts Institute of Technology; Cambridge Massachusetts USA
| | - D. Dong
- Jet Propulsion Laboratory; California Institute of Technology; Pasadena California USA
| | - P. Fang
- Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography; University of California, San Diego; La Jolla California USA
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12
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Tong X, Sandwell DT, Fialko Y. Coseismic slip model of the 2008 Wenchuan earthquake derived from joint inversion of interferometric synthetic aperture radar, GPS, and field data. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jb006625] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Barbot S, Fialko Y, Bock Y. Postseismic deformation due to theMw6.0 2004 Parkfield earthquake: Stress-driven creep on a fault with spatially variable rate-and-state friction parameters. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jb005748] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Perfettini H, Avouac JP. Modeling afterslip and aftershocks following the 1992 Landers earthquake. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jb004399] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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15
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Cavalié O, Doin MP, Lasserre C, Briole P. Ground motion measurement in the Lake Mead area, Nevada, by differential synthetic aperture radar interferometry time series analysis: Probing the lithosphere rheological structure. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jb004344] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Dong D, Fang P, Bock Y, Webb F, Prawirodirdjo L, Kedar S, Jamason P. Spatiotemporal filtering using principal component analysis and Karhunen-Loeve expansion approaches for regional GPS network analysis. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jb003806] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- D. Dong
- Jet Propulsion Laboratory; California Institute of Technology; Pasadena California USA
| | - P. Fang
- Institute of Geophysics and Planetary Physics; Scripps Institution of Oceanography; La Jolla California USA
| | - Y. Bock
- Institute of Geophysics and Planetary Physics; Scripps Institution of Oceanography; La Jolla California USA
| | - F. Webb
- Jet Propulsion Laboratory; California Institute of Technology; Pasadena California USA
| | - L. Prawirodirdjo
- Institute of Geophysics and Planetary Physics; Scripps Institution of Oceanography; La Jolla California USA
| | - S. Kedar
- Jet Propulsion Laboratory; California Institute of Technology; Pasadena California USA
| | - P. Jamason
- Institute of Geophysics and Planetary Physics; Scripps Institution of Oceanography; La Jolla California USA
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17
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Freed AM, Bürgmann R, Calais E, Freymueller J, Hreinsdóttir S. Implications of deformation following the 2002 Denali, Alaska, earthquake for postseismic relaxation processes and lithospheric rheology. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jb003894] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Holocene acceleration of deformation and postseismic relaxation are two hypotheses to explain the present-day deformation in the Central Nevada Seismic Belt (CNSB). Discriminating between these two mechanisms is critical for understanding the dynamics and seismic potential of the Basin and Range province. Interferometric synthetic aperture radar detected a broad area of uplift (2 to 3 millimeters per year) that can be explained by postseismic mantle relaxation after a sequence of large crustal earthquakes from 1915 to 1954. The results lead to a broad agreement between geologic and geodetic strain indicators and support a model of a rigid Basin and Range between the CNSB and the Wasatch fault.
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Affiliation(s)
- Noel Gourmelen
- Division of Marine Geology and Geophysics, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, FL 33149, USA.
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19
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Ouillon G, Sornette D. Magnitude-dependent Omori law: Theory and empirical study. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jb003311] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- G. Ouillon
- Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
- Laboratoire de Physique de la Matière Condensée; CNRS UMR 6622 and Université de Nice-Sophia Antipolis; Nice France
| | - D. Sornette
- Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
- Laboratoire de Physique de la Matière Condensée; CNRS UMR 6622 and Université de Nice-Sophia Antipolis; Nice France
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20
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Meade BJ. Block models of crustal motion in southern California constrained by GPS measurements. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jb003209] [Citation(s) in RCA: 293] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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21
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Pollitz FF. Transient rheology of the upper mantle beneath central Alaska inferred from the crustal velocity field following the 2002 Denali earthquake. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005jb003672] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Fialko Y. Evidence of fluid-filled upper crust from observations of postseismic deformation due to the 1992Mw7.3 Landers earthquake. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2004jb002985] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yuri Fialko
- Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography; University of California San Diego; La Jolla California USA
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23
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Freed AM, Bürgmann R. Evidence of power-law flow in the Mojave desert mantle. Nature 2004; 430:548-51. [PMID: 15282602 DOI: 10.1038/nature02784] [Citation(s) in RCA: 249] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Accepted: 06/24/2004] [Indexed: 11/08/2022]
Abstract
Studies of the Earth's response to large earthquakes can be viewed as large rock deformation experiments in which sudden stress changes induce viscous flow in the lower crust and upper mantle that lead to observable postseismic surface deformation. Laboratory experiments suggest that viscous flow of deforming hot lithospheric rocks is characterized by a power law in which strain rate is proportional to stress raised to a power, n (refs 2, 3). Most geodynamic models of flow in the lower crust and upper mantle, however, resort to newtonian (linear) stress-strain rate relations. Here we show that a power-law model of viscous flow in the mantle with n = 3.5 successfully explains the spatial and temporal evolution of transient surface deformation following the 1992 Landers and 1999 Hector Mine earthquakes in southern California. A power-law rheology implies that viscosity varies spatially with stress causing localization of strain, and varies temporally as stress evolves, rendering newtonian models untenable. Our findings are consistent with laboratory-derived flow law parameters for hot and wet olivine--the most abundant mineral in the upper mantle--and support the contention that, at least beneath the Mojave desert, the upper mantle is weaker than the lower crust.
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Affiliation(s)
- Andrew M Freed
- Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
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24
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Perfettini H, Avouac JP. Postseismic relaxation driven by brittle creep: A possible mechanism to reconcile geodetic measurements and the decay rate of aftershocks, application to the Chi-Chi earthquake, Taiwan. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003jb002488] [Citation(s) in RCA: 282] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- H. Perfettini
- Geological and Planetary Science Division; California Institute of Technology; Pasadena California USA
| | - J.-P. Avouac
- Geological and Planetary Science Division; California Institute of Technology; Pasadena California USA
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25
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Vergnolle M, Pollitz F, Calais E. Constraints on the viscosity of the continental crust and mantle from GPS measurements and postseismic deformation models in western Mongolia. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2002jb002374] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Fred Pollitz
- U.S. Geological Survey; Menlo Park California USA
| | - Eric Calais
- Department of Earth and Atmospheric Sciences; Purdue University; West Lafayette Indiana USA
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Savage JC, Svarc JL, Prescott WH. Near-field postseismic deformation associated with the 1992 Landers and 1999 Hector Mine, California, earthquakes. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2002jb002330] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- J. C. Savage
- U.S. Geological Survey; Menlo Park California USA
| | - J. L. Svarc
- U.S. Geological Survey; Menlo Park California USA
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Abstract
Although motions at the surface of tectonic plates are well determined, the accompanying horizontal mantle flow is not. We have combined observations of surface deformation and upper mantle seismic anisotropy to estimate this flow field for western North America. We find that the mantle velocity is 5.5 +/- 1.5 centimeters per year due east in a hot spot reference frame, nearly opposite to the direction of North American plate motion (west-southwest). The flow is only weakly coupled to the motion of the surface plate, producing a small drag force. This flow field is probably due to heterogeneity in mantle density associated with the former Farallon oceanic plate beneath North America.
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Affiliation(s)
- P G Silver
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA.
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28
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Ivins ER, Raymond CA, James TS. Late-Pleistocene, Holocene and present-day ice load evolution in the Antarctic Peninsula: Models and predicted vertical crustal motion. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/gd029p0133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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29
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Pollitz FF, Wicks C, Thatcher W. Mantle flow beneath a continental strike-slip fault: postseismic deformation after the 1999 Hector Mine earthquake. Science 2001; 293:1814-8. [PMID: 11546869 DOI: 10.1126/science.1061361] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Two recent large earthquakes in the Mojave Desert, California-the magnitude 7.3 1992 Landers and magnitude 7.1 1999 Hector Mine earthquakes-have each been followed by elevated crustal strain rates over periods of months and years. Geodetic data collected after the Hector Mine earthquake exhibit a temporally decaying horizontal velocity field and a quadrant uplift pattern opposite to that expected for localized shear beneath the earthquake rupture. We interpret the origin of this accelerated crustal deformation to be vigorous flow in the upper mantle in response to the stress changes generated by the earthquake. Our results suggest that transient flow in the upper mantle is a fundamental component of the earthquake cycle and that the lower crust is a coherent stress guide coupling the upper crust with the upper mantle.
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Affiliation(s)
- F F Pollitz
- U.S. Geological Survey, 345 Middlefield Road, MS 977, Menlo Park, CA 94025, USA
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30
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Freed AM, Lin J. Delayed triggering of the 1999 Hector Mine earthquake by viscoelastic stress transfer. Nature 2001; 411:180-3. [PMID: 11346791 DOI: 10.1038/35075548] [Citation(s) in RCA: 242] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Stress changes in the crust due to an earthquake can hasten the failure of neighbouring faults and induce earthquake sequences in some cases. The 1999 Hector Mine earthquake in southern California (magnitude 7.1) occurred only 20 km from, and 7 years after, the 1992 Landers earthquake (magnitude 7.3). This suggests that the Hector Mine earthquake was triggered in some fashion by the earlier event. But uncertainties in the slip distribution and rock friction properties associated with the Landers earthquake have led to widely varying estimates of both the magnitude and sign of the resulting stress change that would be induced at the location of the Hector Mine hypocentre-with estimates varying from -1.4 bar (ref. 6) to +0.5 bar (ref. 7). More importantly, coseismic stress changes alone cannot satisfactorily explain the delay of 7 years between the two events. Here we present the results of a three-dimensional viscoelastic model that simulates stress transfer from the ductile lower crust and upper mantle to the brittle upper crust in the 7 years following the Landers earthquake. Using viscoelastic parameters that can reproduce the observed horizontal surface deformation following the Landers earthquake, our calculations suggest that lower-crustal or upper-mantle flow can lead to postseismic stress increases of up to 1-2 bar at the location of the Hector Mine hypocentre during this time period, contributing to the eventual occurrence of the 1999 Hector Mine earthquake. These results attest to the importance of considering viscoelastic processes in the assessment of seismic hazard.
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Affiliation(s)
- A M Freed
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington DC 20015, USA.
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Reilinger RE, Ergintav S, Bürgmann R, McClusky S, Lenk O, Barka A, Gurkan O, Hearn L, Feigl KL, Cakmak R, Aktug B, Ozener H, Töksoz MN. Coseismic and Postseismic Fault Slip for the 17 August 1999, M = 7.5, Izmit, Turkey Earthquake. Science 2000; 289:1519-1524. [PMID: 10968782 DOI: 10.1126/science.289.5484.1519] [Citation(s) in RCA: 222] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We use Global Positioning System (GPS) observations and elastic half-space models to estimate the distribution of coseismic and postseismic slip along the Izmit earthquake rupture. Our results indicate that large coseismic slip (reaching 5.7 meters) is confined to the upper 10 kilometers of the crust, correlates with structurally distinct fault segments, and is relatively low near the hypocenter. Continued surface deformation during the first 75 days after the earthquake indicates an aseismic fault slip of as much as 0.43 meters on and below the coseismic rupture. These observations are consistent with a transition from unstable (episodic large earthquakes) to stable (fault creep) sliding at the base of the seismogenic zone.
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Affiliation(s)
- RE Reilinger
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, E34, 42 Carleton Street, Cambridge, MA 02142, USA. TUBITAK, Marmara Research Center, Earth Science Research Institute, Gebze 41470, Turkey. Department of Earth and Planetary Science, 301 McCone Hall, University of California, Berkeley, Berkeley, CA 94720, USA. General Command of Mapping, Cebece, Ankara, Turkey. Istanbul Technical University, Eurasia Earth Science Institute, Ayazaga, Istanbul, Turkey. Kandilli Observatory, Bogazici University, Istanbul, Turkey. Department of Terrestrial and Planetary Dynamics (UMR 5562) Centre National de Recherche Scientifique, 14 ave. E. Belin 31400 Toulouse, France
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33
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Kaufmann G, Amelung F. Reservoir-induced deformation and continental rheology in vicinity of Lake Mead, Nevada. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/2000jb900079] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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34
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Kenner SJ, Segall P. Postseismic deformation following the 1906 San Francisco earthquake. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/2000jb900076] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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