Transtensional Rupture within a Diffuse Plate Boundary Zone during the 2020 Mw 6.4 Puerto Rico Earthquake

Renier Viltres; Adriano Nobile; Hannes Vasyura-Bathke; Daniele Trippanera; Wenbin Xu; Sigurjón Jónsson

doi:10.1785/0220210261

Transtensional Rupture within a Diffuse Plate Boundary Zone during the 2020 M_w 6.4 Puerto Rico Earthquake

Renier Viltres^*, Adriano Nobile, Hannes Vasyura-Bathke, Daniele Trippanera, Wenbin Xu, Sigurjón Jónsson

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

8 Scopus citations

Abstract

On 7 January 2020, an M_w 6.4 earthquake occurred in the northeastern Caribbean, a few kilometers offshore of the island of Puerto Rico. It was the mainshock of a complex seismic sequence, characterized by a large number of energetic earthquakes illuminating an east–west elongated area along the southwestern coast of Puerto Rico. Deformation fields constrained by Interferometric Synthetic Aperture Radar and Global Navigation Satellite System data indicate that the coseismic movements affected only the western part of the island. To assess the mainshock’s source fault parameters, we combined the geodetically derived coseismic deformation with teleseismic waveforms using Bayesian inference. The results indicate a roughly east–west oriented fault, dipping northward and accommodating ∼1.4 m of transtensional motion. Besides, the determined location and orientation parameters suggest an offshore continuation of the recently mapped North Boquerón Bay–Punta Montalva fault in southwest Puerto Rico. This highlights the existence of unmapped faults with moderate-to-large earthquake potential within the Puerto Rico region.

Original language	English (US)
Pages (from-to)	567-583
Number of pages	17
Journal	Seismological Research Letters
Volume	93
Issue number	2A
DOIs	https://doi.org/10.1785/0220210261
State	Published - Mar 1 2022

Bibliographical note

Funding Information:
This research was supported by the King Abdullah University of Science and Technology (KAUST), under the Award Number BAS/1/1353-01-01. The authors are grateful to P. Martin Mai, Luigi Passarelli, and Yann Klinger for their insightful suggestions to our article. They also thank the Seismological Research Letters Editor-in-Chief Allison Bent and two anonymous reviewers for constructive comments that significantly improved this article. The

Funding Information:
This research was supported by the King Abdullah University of Science and Technology (KAUST), under the Award Number BAS/1/1353-01-01. The authors are grateful to P. Martin Mai, Luigi Passarelli, and Yann Klinger for their insightful suggestions to our article. They also thank the Seismological Research Letters Editor-in-Chief Allison Bent and two anonymous reviewers for constructive comments that significantly improved this article. The ALOS-2 images were provided by the Japan Aerospace Exploration Agency (JAXA) within the projects ER2A2N016 and ER2A2N161.

Publisher Copyright:
© Seismological Society of America.

ASJC Scopus subject areas

Geophysics

Access to Document

10.1785/0220210261

Cite this

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title = "Transtensional Rupture within a Diffuse Plate Boundary Zone during the 2020 Mw 6.4 Puerto Rico Earthquake",

abstract = "On 7 January 2020, an Mw 6.4 earthquake occurred in the northeastern Caribbean, a few kilometers offshore of the island of Puerto Rico. It was the mainshock of a complex seismic sequence, characterized by a large number of energetic earthquakes illuminating an east–west elongated area along the southwestern coast of Puerto Rico. Deformation fields constrained by Interferometric Synthetic Aperture Radar and Global Navigation Satellite System data indicate that the coseismic movements affected only the western part of the island. To assess the mainshock{\textquoteright}s source fault parameters, we combined the geodetically derived coseismic deformation with teleseismic waveforms using Bayesian inference. The results indicate a roughly east–west oriented fault, dipping northward and accommodating ∼1.4 m of transtensional motion. Besides, the determined location and orientation parameters suggest an offshore continuation of the recently mapped North Boquer{\'o}n Bay–Punta Montalva fault in southwest Puerto Rico. This highlights the existence of unmapped faults with moderate-to-large earthquake potential within the Puerto Rico region.",

author = "Renier Viltres and Adriano Nobile and Hannes Vasyura-Bathke and Daniele Trippanera and Wenbin Xu and Sigurj{\'o}n J{\'o}nsson",

note = "Funding Information: This research was supported by the King Abdullah University of Science and Technology (KAUST), under the Award Number BAS/1/1353-01-01. The authors are grateful to P. Martin Mai, Luigi Passarelli, and Yann Klinger for their insightful suggestions to our article. They also thank the Seismological Research Letters Editor-in-Chief Allison Bent and two anonymous reviewers for constructive comments that significantly improved this article. The Funding Information: This research was supported by the King Abdullah University of Science and Technology (KAUST), under the Award Number BAS/1/1353-01-01. The authors are grateful to P. Martin Mai, Luigi Passarelli, and Yann Klinger for their insightful suggestions to our article. They also thank the Seismological Research Letters Editor-in-Chief Allison Bent and two anonymous reviewers for constructive comments that significantly improved this article. The ALOS-2 images were provided by the Japan Aerospace Exploration Agency (JAXA) within the projects ER2A2N016 and ER2A2N161. Publisher Copyright: {\textcopyright} Seismological Society of America.",

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N2 - On 7 January 2020, an Mw 6.4 earthquake occurred in the northeastern Caribbean, a few kilometers offshore of the island of Puerto Rico. It was the mainshock of a complex seismic sequence, characterized by a large number of energetic earthquakes illuminating an east–west elongated area along the southwestern coast of Puerto Rico. Deformation fields constrained by Interferometric Synthetic Aperture Radar and Global Navigation Satellite System data indicate that the coseismic movements affected only the western part of the island. To assess the mainshock’s source fault parameters, we combined the geodetically derived coseismic deformation with teleseismic waveforms using Bayesian inference. The results indicate a roughly east–west oriented fault, dipping northward and accommodating ∼1.4 m of transtensional motion. Besides, the determined location and orientation parameters suggest an offshore continuation of the recently mapped North Boquerón Bay–Punta Montalva fault in southwest Puerto Rico. This highlights the existence of unmapped faults with moderate-to-large earthquake potential within the Puerto Rico region.

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