How Well Do We Really Know the b-Value? New Estimates of Earthquake Magnitude for the Delaware Basin and the Effect of Magnitude Uncertainty on Induced Seismic Hazard Estimates.
Description:
The Delaware Basin, a subset of the greater Permian Basin located in western Texas and southeastern New Mexico, is currently a hotbed of induced seismic activity where the frequency of relatively large magnitude events (M > 4) has been increasing over the last ~5 years including a magnitude 5.4 event in November of 2022. Since large, induced events are quite infrequent, our understanding of seismic hazard, recurrence intervals, and magnitude exceedance for these earthquakes is heavily dependent on a thorough understanding of the magnitude frequency distribution (MFD) and source parameters of numerous small events in the same region. However, magnitude estimates for small earthquakes are often inconsistently measured or simply not available for certain magnitude types.
This project aims to both produce updated estimates of earthquake magnitudes for the Delaware Basin region, paying particular attention to how scaling relationships may change for small and large earthquakes, and to understand the effects of magnitude uncertainty on estimates of MFD and seismic hazard for induced earthquakes. We re-estimate magnitude for events in the Delaware Basin using a relative magnitude method calibrated with coda-envelope-based moment magnitudes developed for the Permian Basin. We also investigate the temporal and spatial variations in MFD and b-value using these updated magnitudes. Previously, we have found that for recent events in western Texas, the use of new relative coda magnitudes yields a decrease in b-value during the 1.5 years between January 2021 and June 2022 signaling a greater proportion of large events in the region than what would have been calculated using originally cataloged magnitudes. We extend this analysis to include events prior to 2021 and events located in southeast New Mexico to facilitate a better understanding of induced seismic hazard in this region.
Session: Advances in Characterizing Seismic Hazard and Forecasting Risk in Hydrocarbon Systems
Type: Oral
Date: 4/18/2023
Presentation Time: 05:30 PM (local time)
Presenting Author: Sydney Gable
Student Presenter: Yes
Invited Presentation:
Authors
Sydney Gable Presenting Author Corresponding Author gablesyd@umich.edu University of Michigan |
Yihe Huang yiheh@umich.edu University of Michigan |
David Shelly dshelly@usgs.gov U.S. Geological Survey |
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How Well Do We Really Know the b-Value? New Estimates of Earthquake Magnitude for the Delaware Basin and the Effect of Magnitude Uncertainty on Induced Seismic Hazard Estimates.
Category
Advances in Characterizing Seismic Hazard and Forecasting Risk in Hydrocarbon Systems