← Back to Sessions

A Joint Inversion Method for Computing Earthquake Stress Drop With Spectra and Spectral Ratios

Description: 

Earthquake stress drop is fundamentally important for understanding the earthquake rupture process, fault strength, and assessing seismic hazard. It is commonly calculated with corner frequency, measured from earthquake spectra, assuming a simple circular rupture model. One significant source of error in determining stress drop in this way is the trade-off between source and path attenuation parameters. To address this issue, we have developed a new method that uses earthquake spectra and spectral ratios to jointly invert source and path attenuation parameters. Our synthetic tests show that this method can effectively mitigate the trade-off between corner frequency and the attenuation parameter. We have been applying this method to analyze earthquakes in the San Francisco Bay Area. In the Bay Area, depth dependence of stress drop was observed in a previous study, but may be due to depth-varying attenuation. Our method accounts for attenuation variations and our preliminary analysis of a set of earthquakes along the northern Hayward Fault shows no depth dependence. We will further assess the data bandwidth requirement for avoiding bias in corner frequency and stress drop.

Session: Understanding and Quantifying the Variability in Earthquake Source Parameter Measurements - I

Type: Oral

Date: 5/3/2024

Presentation Time: 08:30 AM (local time)

Presenting Author: Hao

Student Presenter: No

Invited Presentation: 

Authors