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Anatomy of strike-slip fault tsunami genesis

Elbanna, Ahmed and Abdelmeguid, Mohamed and Ma, Xiao and Amlani, Faisal and Bhat, Harsha S. and Synolakis, Costas and Rosakis, Ares J. (2021) Anatomy of strike-slip fault tsunami genesis. Proceedings of the National Academy of Sciences of the United States of America, 118 (19). Art. No. e2025632118. ISSN 0027-8424. PMCID PMC8126766. https://resolver.caltech.edu/CaltechAUTHORS:20210503-164752484

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Abstract

Tsunami generation from earthquake-induced seafloor deformations has long been recognized as a major hazard to coastal areas. Strike-slip faulting has generally been considered insufficient for triggering large tsunamis, except through the generation of submarine landslides. Herein, we demonstrate that ground motions due to strike-slip earthquakes can contribute to the generation of large tsunamis (>1 m), under rather generic conditions. To this end, we developed a computational framework that integrates models for earthquake rupture dynamics with models of tsunami generation and propagation. The three-dimensional time-dependent vertical and horizontal ground motions from spontaneous dynamic rupture models are used to drive boundary motions in the tsunami model. Our results suggest that supershear ruptures propagating along strike-slip faults, traversing narrow and shallow bays, are prime candidates for tsunami generation. We show that dynamic focusing and the large horizontal displacements, characteristic of strike-slip earthquakes on long faults, are critical drivers for the tsunami hazard. These findings point to intrinsic mechanisms for sizable tsunami generation by strike-slip faulting, which do not require complex seismic sources, landslides, or complicated bathymetry. Furthermore, our model identifies three distinct phases in the tsunamic motion, an instantaneous dynamic phase, a lagging coseismic phase, and a postseismic phase, each of which may affect coastal areas differently. We conclude that near-source tsunami hazards and risk from strike-slip faulting need to be re-evaluated.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1073/pnas.2025632118DOIArticle
https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2025632118/-/DCSupplementalPublisherSupporting Information
https://doi.org/10.31223/X57G72DOIDiscussion Paper
ORCID:
AuthorORCID
Elbanna, Ahmed0000-0003-4079-2607
Abdelmeguid, Mohamed0000-0002-3985-1721
Ma, Xiao0000-0002-2125-0880
Amlani, Faisal0000-0003-4022-8088
Bhat, Harsha S.0000-0003-0361-1854
Synolakis, Costas0000-0003-0140-5379
Rosakis, Ares J.0000-0003-0559-0794
Additional Information:© 2021 The Author(s). Published under the PNAS license. Contributed by Ares J. Rosakis, March 22, 2021 (sent for review December 13, 2020; reviewed by Michel Bouchon, Frederic Dias, and David D. Oglesby) A.E. was supported by NSF CAREER Award 1753249, and A.J.R. was supported by the Caltech/Mechanical and Civil Engineering Big Ideas Fund and the Caltech Terrestrial Hazard Observation and Reporting Center. This research is part of the Blue Waters sustained-petascale computing project, which is supported by NSF Awards OCI-0725070 and ACI-1238993, the State of Illinois, and, as of December 2019, the National Geospatial-Intelligence Agency. Blue Waters is a joint effort of the University of Illinois at Urbana–Champaign and its National Center for Supercomputing Applications. H.S.B. was supported by European Research Council Consolidator Grant PERSISMO a#865411. C.S was supported by NSF Award 1906162, Field Survey of the September 27, 2018, Sulawesi Tsunami. Data Availability. All study data are included in the article and/or supporting information. Author contributions: A.E. and A.J.R. designed research; A.E., M.A., X.M., and A.J.R. performed research; A.E., M.A., X.M., F.A., H.S.B., C.S., and A.J.R. analyzed data; and A.E., M.A., X.M., F.A., H.S.B., C.S., and A.J.R. wrote the paper. Reviewers: M.B., Université Grenoble Alpes; F.D., University College Dublin; and D.D.O., University of California, Riverside. The authors declare no competing interest. This article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2025632118/-/DCSupplemental.
Group:GALCIT
Funders:
Funding AgencyGrant Number
Caltech Big Ideas FundUNSPECIFIED
NSFEAR-1753249
Caltech Terrestrial Hazard Observation and Reporting (THOR) CenterUNSPECIFIED
NSFOCI-0725070
NSFACI-1238993
State of IllinoisUNSPECIFIED
National Geospatial-Intelligence AgencyUNSPECIFIED
European Research Council (ERC)865411
NSFCMMI-1906162
Subject Keywords:tsunamis in bays; strike-slip faults; supershear ruptures; vertical and horizontal bathymetry motions; run-up
Issue or Number:19
PubMed Central ID:PMC8126766
Record Number:CaltechAUTHORS:20210503-164752484
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210503-164752484
Official Citation:Anatomy of strike-slip fault tsunami genesis Ahmed Elbanna, Mohamed Abdelmeguid, Xiao Ma, Faisal Amlani, Harsha S. Bhat, Costas Synolakis, Ares J. Rosakis Proceedings of the National Academy of Sciences May 2021, 118 (19) e2025632118; DOI: 10.1073/pnas.2025632118
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108951
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:04 May 2021 14:40
Last Modified:05 Aug 2021 21:23

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