Between and Within Region Comparison of Source Parameters: Applications of the Coda Calibration Tool (CCT)
Description:
Between and within region comparison of source parameters (e.g., seismic moment and stress drop) is hampered by the inconsistencies that arise when different approaches are considered (Baltay et al., 2022). To overcome this problem, we present the application of the Coda Calibration Tool (CCT) to different tectonic settings for closer analysis of the regional variations. CCT implements the empirical methodology outlined in Mayeda et al., (2003), which provides reliable source spectra even for events recorded by sparse local and regional seismic networks (e.g., Morasca et al., 2022). We use independent ground-truth (GT) reference spectra for which apparent stresses are independently calculated through the coda spectral ratio (Mayeda et al., 2007), to break the path and site trade-off. The use of GT spectra eliminates the need to assume source scaling for the region, reducing the impact of a-priori model assumptions on the interpretation of scaling laws of source parameters and their variability. The CCT is a freely available Java-based code (https://github.com/LLNL/coda-calibration-tool) that significantly reduces the coda calibration effort and provides calibration parameters for future use in the same region for routine processing.
Recently, several studies applied CCT in very different tectonic contexts, including (1) earthquakes in tectonically active regions (e.g., central Italy, Puerto Rico, southern California, Utah); (2) induced earthquakes in southern Kansas and northern Oklahoma; and (3) moderate-sized earthquakes in stable continental regions such as in Eastern Canada and the United Kingdom. We summarize the results from these studies here, showing that the application of a consistent methodological framework and the robustness demonstrated by the results of the seismic coda analysis, allow comparison of source scaling relationships for different tectonic settings over a wide range of magnitudes.
W.R. Walter and J. Barno’s portion prepared by LLNL under Contract DE-AC52-07NA27344
Session: Understanding the Variability in Earthquake Stress Drop Measurements [Poster]
Type: Poster
Date: 4/20/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Kevin Mayeda
Student Presenter: No
Invited Presentation:
Authors
Kevin Mayeda Presenting Author Corresponding Author kevin.mayeda@gmail.com Air Force Technical Applications Center |
Paola Morasca paola.morasca@ingv.it Istituto Nazionale Geofisica e Vulcanologia |
Katherine Whidden katherine.whidden@utah.edu University of Utah |
Allison Bent allison.bent@nrcan-rncan.gc.ca Natural Resources Canada |
Jorge Roman-Nieves jorge.roman-nieves.1@us.af.mil Air Force Technical Applications Center |
David Shelly dshelly@usgs.gov U.S. Geological Survey |
Charlie Peach cp17736@bristol.ac.uk AWE Blacknest |
Stewart Nipress stuart@blacknest.gov.uk AWE Blacknest |
David Green dgreen@blacknest.gov.uk AWE Blacknest |
William R Walter walter5@llnl.gov Lawrence Livermore National Laboratory, Lafayette, California, United States |
Justin Barno barno1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Dino Bindi bindi@gfz-potsdam.de GFZ Potsdam, Potsdam, , Germany |
Between and Within Region Comparison of Source Parameters: Applications of the Coda Calibration Tool (CCT)
Category
Understanding the Variability in Earthquake Stress Drop Measurements