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WITHDRAWN Diffuse Transtensional Deformation in the 2020 Puerto Rico Earthquake Sequence

Description: 

WITHDRAWN On January 7^th, 2020, a damaging M6.4 earthquake occurred in the northeastern Caribbean, a few tens of kilometers to the southwest of Ponce in Puerto Rico. It was the mainshock of a complex seismic sequence characterized by energetic and shallow-depth seismicity distributed along an east-west elongated area just offshore of the island’s south coast. Furthermore, the ground shaking generated by the main events of the sequence produced significant damage to buildings and cost at least one casualty. Here we estimate the fault parameters of the main event of the sequence by combining Interferometric Synthetic Aperture Radar (InSAR), Global Navigation Satellite System (GNSS), and teleseismic waveforms using Bayesian inference. The geodetic data provide only on-land displacements showing that the coseismic deformation was limited to southwestern Puerto Rico and mainly in the area near Guayanilla bay. Furthermore, the geodetic observations suggest that an inland segment of the recently mapped North Boqueron Bay-Punta Montalva fault (NBBPM) may have been reactivated. The Bayesian results, on the other hand, support an east-west oriented fault, dipping northward and accommodating ∼1.4 m of transtensional motion, with location and orientation parameters rather suggesting an offshore continuation of the NBBPM fault was activated. Together, the results indicate transtensional faulting in response to active diffuse deformation affecting southwestern Puerto Rico and highlight unmapped faults with moderate to large earthquake potential in the Puerto Rico region.

Session: The 2020-2021 Southwest Puerto Rico Seismic Sequence: Current State of Knowledge and Implications [Poster]

Type: Poster

Date: 4/18/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Adriano Nobile

Student Presenter: No

Invited Presentation: 

Authors