Coda Calibration Technique for Reliable Moment Magnitudes and Source Characterization in SW USA and NNSS
Description:
Reliable estimates of moment magnitude and source mechanism for seismic events are essential parts of understanding a seismic region and source characterization of earthquakes and explosions. Although waveform modeling-based methods (e.g. moment tensor inversion) is routinely used for moderate-sized and larger earthquakes (M>4 for regional catalogs), these inversions require good azimuthal distribution of stations and very good knowledge of the Earth’s structure in the region, which makes waveform modeling difficult to perform on smaller earthquakes. Robust regional-specific seismic event characterization requires well-calibrated regional seismic stations to produce reliable and stable estimates of earthquake source parameters which can be derived using the coda wave calibration method. The Coda Calibration Tool (CCT) is an application designed for calibrating 1D shear wave coda measurement models to observed data using a small set of reference moment magnitudes calculated from other methods, such as moment tensor inversion. These calibrated measurement models can then be used to generate coda moment magnitude (MW) and apparent stress estimated from stable source spectra.
In this presentation, we describe the methodology of using CCT for calibrating a region of seismic stations encompassing and surrounding the Nevada National Security Site (NNSS), a region of interest due to previous multi-physics experiments. The results from applying this calibration on earthquakes (with a range of magnitudes) and on chemical explosions, exemplify the stability of the calibration that we hope to be used to facilitate reliable estimates of moment magnitude and source mechanism for seismic events at local and regional distances in Nevada and surrounding regions in the future.
Session: Advances in Reliable Earthquake Source Parameter Estimation - III
Type: Oral
Date: 4/16/2025
Presentation Time: 02:15 PM (local time)
Presenting Author: Louisa
Student Presenter: No
Invited Presentation:
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Authors
Louisa Barama Presenting Author Corresponding Author barama1@llnl.gov Lawrence Livermore National Laboratory |
Andrea Chiang chiang4@llnl.gov Lawrence Livermore National Laboratory |
Rengin Gok gok1@llnl.gov Lawrence Livermore National Laboratory |
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Coda Calibration Technique for Reliable Moment Magnitudes and Source Characterization in SW USA and NNSS
Category
Advances in Reliable Earthquake Source Parameter Estimation