Exploring uncertainty in moment estimation for small earthquakes using the coda envelope method
Anne Patton, Colin N. Pennington, William Walter, & Daniel T. TrugmanPublished September 8, 2024, SCEC Contribution #14029, 2024 SCEC Annual Meeting Poster #063
Compiling source parameter estimates for small earthquakes is important both for our understanding of earthquake physics and for accurately assessing earthquake hazard. Reliable source parameter estimates are difficult to achieve for small earthquakes, in part due to our inability to accurately model the relevant physical processes at high frequencies. The coda envelope methodology developed by Mayeda and Walter (1996) and Mayeda et al. (2003) can mitigate this concern and estimate the moment of small earthquakes by determining the parameters that control the shape of the S-wave coda envelope while eliminating path effects by minimizing the scatter between seismic stations. We use an open-source implementation of this technique called the Coda Calibration Tool (CCT; Barno, 2017) to estimate moment magnitude of small earthquakes (ML 0-3) near Rock Valley, Nevada. The Rock Valley dataset is of particular interest because it allows us to explore the changes in uncertainties of the coda calibration method with earthquake size. We demonstrate that the epistemic uncertainty in the apparent stress value assumed by the CCT algorithm can influence magnitude estimates of small earthquakes. We also explore the effects of source depth on our MW estimates. These results provide valuable insight into the nature of shallow earthquakes in this region, and inform future analysis and modeling efforts for nuclear monitoring and seismic hazard.
Key Words
moment magnitude, small earthquakes, coda calibration, Nevada
Citation
Patton, A., Pennington, C. N., Walter, W., & Trugman, D. T. (2024, 09). Exploring uncertainty in moment estimation for small earthquakes using the coda envelope method. Poster Presentation at 2024 SCEC Annual Meeting.
Related Projects & Working Groups
Seismology
