Earthquake Waveform Similarity as a Tool to Image Stress and Fault Complexity: Application to the 2019 Ridgecrest Earthquake Sequence

Session: Waveform Cross-Correlation-Based Methods in Observational Seismology
Type: Oral
Date: 4/30/2020
Time: 08:45 AM
Room: 230 + 235
Description: 

While the rupture processes of nearby earthquakes are often highly similar, characterizing the differences can lend insight into the details of the local stress field and in-situ fault network. Here we perform a comprehensive analysis of earthquake waveform similarity in the vicinity of Ridgecrest, California, quantifying how similar each earthquake is to its neighbors through cross-correlation of full waveforms. The July 2019 Ridgecrest mainshocks impose a step reduction in earthquake similarity throughout the region, which suggests substantial variability in the residual stress field and activated fault structures on length scales of hundreds of meters or less. Among the Ridgecrest aftershocks, we observe coherent spatial variations of earthquake similarity along the rupture trace of the M7.1 mainshock. We also document several dozen instances of anti-similar aftershock pairs, with waveforms that are nearly identical at multiple stations but with reversed polarity. These observations provide new, high-resolution constraints on stress transfer and faulting complexity throughout the Ridgecrest earthquake sequence.

Presenting Author: Daniel Trugman

Authors