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Absolute Centroid Location of Submarine Earthquakes from 3D Waveform Modeling of Water Reverberations

Castellanos, Jorge C. and Zhan, Zhongwen and Wu, Wenbo (2020) Absolute Centroid Location of Submarine Earthquakes from 3D Waveform Modeling of Water Reverberations. Journal of Geophysical Research. Solid Earth, 125 (5). Art. No. e2019JB018941. ISSN 2169-9313. https://resolver.caltech.edu/CaltechAUTHORS:20200325-141609755

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Abstract

Oceanic transform faults (OTFs) represent an attractive tectonic environment to investigate how slip is accommodated within the crust. However, as most of these fault systems grow in the deep ocean, where few local seismic observations are available, characterizing their earthquake behavior is complicated and remains a formidable challenge. Here we present a novel approach for retrieving precise centroid locations of submarine earthquakes that is based on the modeling of water phases in teleseismic records. Using a hybrid method for simulating far‐field body waves with 3D source‐side structures, we demonstrate that the scattered energy generated by the continuous bounces of an earthquake's P‐wave trapped in the ocean is modelable and carries information about its source location. As a case study, we use a realistic bathymetry model of the Gofar transform fault on the East Pacific Rise and simulate the seismic wavefield at US Array stations for four of its moderate‐sized (Mw5.0+) earthquakes. Our modeling results show that water phases are sensitive to a ∼5 km change in the earthquake's horizontal location and that a remarkable agreement between observed and synthetic water phases is achieved when the location of an event is close to its true one. We then relocate three of these events by systematically computing their water phases in candidate locations until a satisfactory waveform fit is achieved. This analysis technique paves a new route for studying earthquake source properties in isolated marine environments and serves as a mean to investigate the seismic behavior of OTFs on a global scale.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1029/2019JB018941DOIArticle
ORCID:
AuthorORCID
Castellanos, Jorge C.0000-0002-0103-6430
Zhan, Zhongwen0000-0002-5586-2607
Wu, Wenbo0000-0002-6249-8065
Additional Information:© 2020 American Geophysical Union. Received 22 OCT 2019; Accepted 23 MAR 2020; Accepted article online 25MAR 2020. The facilities of IRIS Data Services, and specifically the IRIS Data Management Center, were used for access to waveforms (https://www.iris.edu/hq/). Centroid moment tensor solutions were obtained from the Global CMT catalog (https://www.globalcmt.org/). We gratefully thank two anonymous reviewers for their careful and constructive suggestions. Figures were made using the Generic Mapping Tools v.4.5.9 (www.soest.hawaii.edu/gmt).
Group:Seismological Laboratory
Subject Keywords:Waveform modeling; Oceanic transform fault; Water phases
Issue or Number:5
Record Number:CaltechAUTHORS:20200325-141609755
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200325-141609755
Official Citation:Castellanos, J. C., Zhan, Z., & Wu, W. ( 2020). Absolute centroid location of submarine earthquakes from 3D waveform modeling of water reverberations. Journal Geophysical Research: Solid Earth, 125, e2019JB018941. https://doi.org/10.1029/2019JB018941
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:102108
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:25 Mar 2020 21:58
Last Modified:15 May 2020 16:30

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