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New Insights Into the 2019 Puerto Rico Sequence - a Combined Study Based on Correlation Fractal Dimension and Static Stress Changes

Description: 

Puerto Rico, situated in a complex geotectonic setting, has undergone destructive earthquakes and tsunamigenic events in the recent past. The seismicity trend witnessed a surge in recent years, and the seismicity was denser towards the South-west of the island of Puerto Rico. We used the fractal correlation dimension (D_c), seismicity trend, and coulomb static stress pattern analysis during this study to get more insights on the sequence of earthquakes that started towards the end of 2019 with more reference to the M_w 6.4 event on 7^th January 2020. There was significant clustering of events and a noticeable drop in the value of D_c before the M_w 6.4 event hinting at a numerical precursor. Also, the coulomb static stress analysis changed notably after the onset of the sequence of earthquakes that started towards the end of 2019. A positive stress pattern was observed in the study region till 2019 due to the historical earthquakes over 30 years. The stress pattern changed after the 2019 sequence, with higher stress levels observed in the south–southwest region of the island of Puerto Rico. It is evident that the area is undergoing tectonic readjustments following the increased stress observed across the South Lajas Fault, Punta Montalva fault, Salinas fault, and so on. Assessing the D_c and the static stress patterns, we recognized low D_c windows before the events with increased stress close to the shock’s epicenter from the coulomb stress analysis.

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

Type: Oral

Date: 4/18/2023

Presentation Time: 10:00 AM (local time)

Presenting Author: Tejaswini Mangalagiri

Student Presenter: No

Invited Presentation: 

Authors