Developing a Joint Regional Waveform-Insar Moment Tensor Inversion: Application to 6th North Korean Nuclear Test
Session: Explosion Seismology Applications and Advances II
Type: Oral
Date: 4/19/2021
Presentation Time: 02:00 PM Pacific
Description:
On 3 September 2017, the Democratic People’s Republic of Korea conducted its largest nuclear test (DPRK2017). This event is the largest man-made explosion ever recorded by orbital radar systems and provides a unique dataset with which to develop new methods of source inversion (Wang et al. 2018). Even though regional distance seismic MT inversion methods have identified this event as an explosion (Chiang et al., 2018), we have found that the best surface wave and first motion solution fails to fit the static deformation field from the SAR data (e.g. Dreger et al., 2017). However, we have found that a subspace of best-fitting models can satisfy the surface deformation field and reduce the overall uncertainty in the moment tensor solution. To develop a joint inversion method we develop Green’s functions using the SW4 finite-difference code to accurately model surface topography effects on the seismic wave field. We have generated Green’s functions for a source volume comprised of XYZ sources. We perform a grid search of moment tensor solutions over the source volume to find the best fitting location, depth and moment tensor for the event. We also compare different velocity models for this inaccessible region. Our initial results show that we can explain 50% horizontal static ground deformation using a composition of 3 different point-sources that accounts for the finite extent of the explosive source with a layered model (Pabian and Coblentz, 2015). We have succeeded in constraining the large subset of possible MT solutions in a waveform and first-motion inversion (Nayak and Dreger, 2015). We will present static field only, joint static, regional waveform and first-motion point-source solutions, and multiple point-source solutions to account for source finiteness.
Presenting Author: Rodrigo Chi-Duran
Student Presenter: Yes
Authors
Rodrigo Chi-Duran Presenting Author Corresponding Author rodrigo.chi@berkeley.edu University of California, Berkeley |
Douglas Dreger ddreger@berkeley.edu University of California, Berkeley |
Arthur Rodgers rodgers7@llnl.gov Lawrence Livermore National Laboratory |
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Developing a Joint Regional Waveform-Insar Moment Tensor Inversion: Application to 6th North Korean Nuclear Test
Category
Explosion Seismology Applications and Advances