The M6.4 Mainshock in the 2020 Southwestern Puerto Rico Seismic Sequence: New Insights From Joint Inversion
Description:
The U.S. Geological Survey National Earthquake Information Center (NEIC) now routinely incorporates regional strong motion, high-rate and static Global Navigation Satellite System (GNSS), and Interferometric Synthetic Aperture (InSAR) observations into finite-fault model (FFM) products when such observations are available. The inclusion of these data sets allows for modeling of smaller earthquakes than was typical of NEIC FFMs (often M7 or larger). Considering this advancement, we revisited the January 7, 2020, M6.4 earthquake in Puerto Rico. This earthquake was part of the 2020-2021 Southwestern Puerto Rico (SWPR) seismic sequence, an active sequence with seismicity distributed across a complex set of structures within the Puerto Rico and Virgin Islands block that illuminates new faults previously not recognized. We refined the FFM for this event considering data from broadband teleseismic waveforms, regional strong-motion accelerometers, high-rate GNSS stations, GNNS static offsets, and InSAR pairs. Modeling this event presents some challenges due to the likelihood that multiple causative faults were involved, with a combination of normal and strike-slip motion, and its offshore location. However, the inclusion of regional data allowed us to improve the resolution of our model and investigate the plausibility of a more complex, geologically realistic, fault geometry that includes two fault segments with different rake directions. Our refined model prefers slower rupture velocity and longer rise time than average for an event of this magnitude, suggesting a slowly evolving source rupture process. These results will lead to a better understanding of the seismotectonic characteristics of the 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: Margarita M. Solares-Colón
Student Presenter: Yes
Invited Presentation:
Authors
Margarita Solares-Colón Presenting Author Corresponding Author msolares@uoregon.edu University of Oregon |
Dara Goldberg degoldberg@usgs.gov U.S. Geological Survey |
William Yeck wyeck@usgs.gov U.S. Geological Survey |
Diego Melgar dmelgarm@uoregon.edu University of Oregon |
Elizabeth Vanacore elizabeth.vanacore@upr.edu University of Puerto Rico |
Alberto López-Venegas alberto.lopez3@upr.edu University of Puerto Rico |
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The M6.4 Mainshock in the 2020 Southwestern Puerto Rico Seismic Sequence: New Insights From Joint Inversion
Category
The 2020-2021 Southwest Puerto Rico Seismic Sequence: Current State of Knowledge and Implications