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Craiu A, Ferrand TP, Manea EF, Vrijmoed JC, Mărmureanu A. A switch from horizontal compression to vertical extension in the Vrancea slab explained by the volume reduction of serpentine dehydration. Sci Rep 2022; 12:22320. [PMID: 36566238 DOI: 10.1038/s41598-022-26260-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 12/13/2022] [Indexed: 12/25/2022] Open
Abstract
The Vrancea slab, Romania, is a subducted remnant of the Tethyan lithosphere characterized by a significant intermediate-depth seismicity (60-170 km). A recent study showed a correlation between this seismicity and major dehydration reactions, involving serpentine minerals up to 130 km depth, and high-pressure hydrated talc deeper. Here we investigate the potential link between the triggering mechanisms and the retrieved focal mechanisms of 940 earthquakes, which allows interpreting the depth distribution of the stress field. We observe a switch from horizontal compression to vertical extension between 100 and 130 km depth, where the Clapeyron slope of serpentine dehydration is negative. The negative volume change within dehydrating serpentinized faults, expected mostly sub-horizontal in the verticalized slab, could well explain the vertical extension recorded by the intermediate-depth seismicity. This apparent slab pull is accompanied with a rotation of the main compressive stress, which could favour slab detachments in active subduction zones.
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Affiliation(s)
- Andreea Craiu
- National Institute for Earth Physics, Calugareni, 12, Măgurele, Ilfov, Romania
| | - Thomas P Ferrand
- Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstraße 74-100, 12249, Berlin, Germany. .,Institut des Sciences de la Terre d'Orléans, UMR-7327, Université d'Orléans - CNRS, 1A Rue de la Ferollerie, 45100, Orléans, France.
| | - Elena F Manea
- National Institute for Earth Physics, Calugareni, 12, Măgurele, Ilfov, Romania.,GNS Science, PO Box 30-368, Lower Hutt, New Zealand
| | - Johannes C Vrijmoed
- Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstraße 74-100, 12249, Berlin, Germany
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Özcebe AG, Tiganescu A, Ozer E, Negulescu C, Galiana-Merino JJ, Tubaldi E, Toma-Danila D, Molina S, Kharazian A, Bozzoni F, Borzi B, Balan SF. Raspberry Shake-Based Rapid Structural Identification of Existing Buildings Subject to Earthquake Ground Motion: The Case Study of Bucharest. SENSORS (BASEL, SWITZERLAND) 2022; 22:4787. [PMID: 35808283 PMCID: PMC9268860 DOI: 10.3390/s22134787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/19/2022] [Accepted: 06/21/2022] [Indexed: 06/15/2023]
Abstract
The Internet of things concept empowered by low-cost sensor technologies and headless computers has upscaled the applicability of vibration monitoring systems in recent years. Raspberry Shake devices are among those systems, constituting a crowdsourcing framework and forming a worldwide seismic network of over a thousand nodes. While Raspberry Shake devices have been proven to densify seismograph arrays efficiently, their potential for structural health monitoring (SHM) is still unknown and is open to discovery. This paper presents recent findings from existing buildings located in Bucharest (Romania) equipped with Raspberry Shake 4D (RS4D) devices, whose signal recorded under multiple seismic events has been analyzed using different modal identification algorithms. The obtained results show that RS4D modules can capture the building vibration behavior despite the short-duration and low-amplitude excitation sources. Based on 15 RS4D device readings from five different multistorey buildings, the results do not indicate damage in terms of modal frequency decay. The findings of this research propose a baseline for future seismic events that can track the changes in vibration characteristics as a consequence of future strong earthquakes. In summary, this research presents multi-device, multi-testbed, and multi-algorithm evidence on the feasibility of RS4D modules as SHM instruments, which are yet to be explored in earthquake engineering.
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Affiliation(s)
- Ali Güney Özcebe
- European Centre for Training and Research in Earthquake Engineering (EUCENTRE), 27100 Pavia, Italy; (A.G.Ö.); (F.B.); (B.B.)
| | - Alexandru Tiganescu
- National Institute for Earth Physics, Calugareni 12, 077125 Magurele, Romania; (D.T.-D.); (S.F.B.)
| | - Ekin Ozer
- Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow G1 1XQ, UK; (E.O.); (E.T.)
- School of Civil Engineering, University College Dublin, D04V1W8 Dublin, Ireland
| | | | - Juan Jose Galiana-Merino
- Department of Physics, Systems Engineering and Signal Theory, University of Alicante, Crta. San Vicente del Raspeig, s/n, 03080 Alicante, Spain
- University Institute of Physics Applied to Sciences and Technologies, University of Alicante, Crta. San Vicente del Raspeig, s/n, 03080 Alicante, Spain
| | - Enrico Tubaldi
- Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow G1 1XQ, UK; (E.O.); (E.T.)
| | - Dragos Toma-Danila
- National Institute for Earth Physics, Calugareni 12, 077125 Magurele, Romania; (D.T.-D.); (S.F.B.)
| | - Sergio Molina
- Department of Applied Physics, University of Alicante, Crta. San Vicente del Raspeig, s/n, 03080 Alicante, Spain;
- Multidisciplinary Institute for Environmental Studies, University of Alicante, Crta. San Vicente del Raspeig, s/n, 03080 Alicante, Spain;
| | - Alireza Kharazian
- Multidisciplinary Institute for Environmental Studies, University of Alicante, Crta. San Vicente del Raspeig, s/n, 03080 Alicante, Spain;
| | - Francesca Bozzoni
- European Centre for Training and Research in Earthquake Engineering (EUCENTRE), 27100 Pavia, Italy; (A.G.Ö.); (F.B.); (B.B.)
| | - Barbara Borzi
- European Centre for Training and Research in Earthquake Engineering (EUCENTRE), 27100 Pavia, Italy; (A.G.Ö.); (F.B.); (B.B.)
| | - Stefan Florin Balan
- National Institute for Earth Physics, Calugareni 12, 077125 Magurele, Romania; (D.T.-D.); (S.F.B.)
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