Virtual Seismometer Method for Fault Orientation Analysis in Southern Kansas
Session: Advances in Seismic Interferometry: Theory, Computation and Applications [Poster]
Type: Poster
Date: 4/22/2021
Presentation Time: 11:30 AM Pacific
Description:
We analyze spatial and temporal changes in fault rupture styles and orientations near a site of active fluid disposal in Southern Kansas. Our approach is based on the virtual seismometer method (VSM), an interferometric technique which uses the reciprocity principle to capture the wavefield between seismic events (Curtis et al., 2009, Nature Geoscience). VSM is very sensitive to the source parameters (location, mechanism and magnitude) and we can use it to invert for full moment tensor solutions, particularly for events within dense clouds of microseismicity.
In this study, we apply VSM to induced events in Southern Kansas. The data are records of micro events from a dense seismicity catalog created with matched filter techniques (Cochran et al., 2018, JGR). From this, we calculate full moment tensor solutions for individual events and use the results to determine fault rupture and orientation information. Focusing on a subset of events of magnitude 1-3 that occurred during 2015, we first derive a normalized waveform similarity coefficient map (Trugman, 2020, GRL), which confirms spatial changes in fault rupture. Results of VSM-based full moment tensor inversion of this same subset of events show a range of non-double couple components. The presence of non-double couple components has also been suggested in fluid related mechanism of induced seismicity in other studies (e.g., Wang et al, 2018, GRL).
The advantage of VSM, contrary to other classical moment tensor inversion techniques, is to considerably reduce the modeled numerical domain to the region directly around the micro events cloud, which lowers computational cost, permits to reach higher frequency resolution, and suppresses the impact of the Earth structural model uncertainties outside the micro events cloud.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-818264
Presenting Author: Christina Morency
Student Presenter: No
Authors
Christina Morency Presenting Author Corresponding Author morency1@llnl.gov Lawrence Livermore National Laboratory |
Eric Matzel matzel1@llnl.gov Lawrence Livermore National Laboratory |
Kayla Kroll kroll5@llnl.gov Lawrence Livermore National Laboratory |
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Virtual Seismometer Method for Fault Orientation Analysis in Southern Kansas
Category
Advances in Seismic Interferometry: Theory, Computation and Applications