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Moment Tensor Inversion and Its Uncertainty from Green’s Functions with Different Algorithms

Description: 

Moment tensor inversion (MTI) has been routinely used by the seismology community to study the characteristics and the identification of source types for earthquakes and explosions. MTI has been further used to quantify uncertainty surfaces associated with each event type obtained by the moment tensor decomposition. In this study we are investigating uncertainties resulted due to the use of Green’s Functions (GFs) computed by the frequency wavenumber integration and finite difference techniques for the same velocity model. Our focus here is to investigate the isotropic moments, especially for the explosions at the Nevada Test Site. To this end, we are investigating effects of the GFs computed allowing the velocity models to have random fluctuations in the geophysical parameters. We are focusing on the estimating the uncertainties in each source type of the decomposed mechanism that is mainly due to the uncertainties in velocity models using a Monte Carlo approach. We are also attempting to compare the MTI solutions with those determined by using a grid-search technique for the double-couple (DC) mechanism. For explosion sources, we perform a linear-inversion for the seismic moments of the DC, isotropic and compensated linear vector dipole (CLVD) sources for each possible DC mechanism to minimize the misfit between the synthetic and observed waveforms.

Session: Advancements in Forensic Seismology and Explosion Monitoring - III

Type: Oral

Date: 5/2/2024

Presentation Time: 02:00 PM (local time)

Presenting Author: Rongmao

Student Presenter: No

Invited Presentation: 

Authors