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Analyzing Stress Drops and Other Earthquake Parameters from the 2019 Ridgecrest Earthquake Sequence

Session: Exploring Rupture Dynamics and Seismic Wave Propagation Along Complex Fault Systems [Poster]

Type: Poster

Date: 4/19/2021

Presentation Time: 03:45 PM Pacific

Description: 

As part of the Community Stress Drop Validation Study, we examine stress drops from the 2019 Ridgecrest Earthquake sequence to understand the sources of variability. Because earthquake stress drop is related to the energy released from an earthquake rupture, how it scales with different variables such as magnitude, moment, depth, is of interest. However, considerable scatter and uncertainty in estimates makes this difficult. The 2019 Ridgecrest earthquake sequence had 3,557 earthquakes of magnitude M2+ recorded in the first two weeks alone, the largest magnitude being 7.1. This earthquake sequence provided a wealth of high-quality data that has been analyzed by multiple researchers using multiple methods.

To understand how stress drops from different researchers and approaches differ, we examine two stress drop data sets: Trugman (2020) who uses a spectral decomposition method, and Arias stress drops calculated in Parker et al. (2020). We compare these stress drops by making correlation plots in MATLAB to understand which events are similar or different. We examine not just the stress drop values, but also how the seismic moments and corner frequencies compare between methods. We try to understand if the similarities and differences between the datasets are indicators of other physical earthquake information, to get better knowledge of the foundation of these events. We then choose several specific earthquakes, including earthquakes whose stress drops both agree and disagree, studied by Trugman (2020) and Parker et al. (2020). We analyze these events in more detail to measure and compare their spectral properties. This research informs how to model future earthquakes and helps us to better prepare for upcoming seismic events.

Presenting Author: Vivian G. Rosas

Student Presenter: Yes

Authors