Poster #116, Stress and Deformation Over Time (SDOT)
Preseismic and Post-seismic Transient Strain Anomaly Patterns Before and After the 2019 Ridgecrest Earthquake Sequence
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Poster Presentation
2020 SCEC Annual Meeting, Poster #116, SCEC Contribution #10763 VIEW PDF
ght-lateral shear zone along NW-trending planes in every late spring across the region of the epicenters.
We further quantify the full horizontal transient fields in the regions near Ridgecrest following the 2019 Ridgecrest Earthquake Sequence to investigate the influence of the post-seismic relaxation on the adjacent fault zones. In June 2020, two large earthquakes occurred within the region of our analysis: the M 5.5 earthquake of June 3 in Ridgecrest region and the M 5.8 earthquake of June 24 near the Lone Pine fault zone, which is about 85km NNW of Ridgecrest. Our horizontal transient strain solution shows that the post-seismic effect of the 2019 events has been lasting up to the present and has been perturbing the typical seasonal horizontal strain patterns. In May 2020, a month prior to the M 5.5 and M 5.8 events, our solution predicts extensional dilatational strain in both of the epicenter regions of the 2020 earthquakes. Note that before the 2019 events, contractional dilatation typically developed in the region surrounding the epicenter of the M 5.8 event in late spring. Furthermore, a zone of right-lateral shear is significantly enhanced in Ridgecrest region in the late spring of 2020 following the 2019 events.
These results are consistent with the 2019 Ridgecrest Sequence being triggered by the repeating seasonal strain dilatation and shear patterns, captured by cGPS. Furthermore the post-seismic signals following the 2019 Ridgecrest events have enhanced extensional dilatation and shear patterns throughout Ridgecrest and further north along the Lone Pine fault zone.
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We further quantify the full horizontal transient fields in the regions near Ridgecrest following the 2019 Ridgecrest Earthquake Sequence to investigate the influence of the post-seismic relaxation on the adjacent fault zones. In June 2020, two large earthquakes occurred within the region of our analysis: the M 5.5 earthquake of June 3 in Ridgecrest region and the M 5.8 earthquake of June 24 near the Lone Pine fault zone, which is about 85km NNW of Ridgecrest. Our horizontal transient strain solution shows that the post-seismic effect of the 2019 events has been lasting up to the present and has been perturbing the typical seasonal horizontal strain patterns. In May 2020, a month prior to the M 5.5 and M 5.8 events, our solution predicts extensional dilatational strain in both of the epicenter regions of the 2020 earthquakes. Note that before the 2019 events, contractional dilatation typically developed in the region surrounding the epicenter of the M 5.8 event in late spring. Furthermore, a zone of right-lateral shear is significantly enhanced in Ridgecrest region in the late spring of 2020 following the 2019 events.
These results are consistent with the 2019 Ridgecrest Sequence being triggered by the repeating seasonal strain dilatation and shear patterns, captured by cGPS. Furthermore the post-seismic signals following the 2019 Ridgecrest events have enhanced extensional dilatation and shear patterns throughout Ridgecrest and further north along the Lone Pine fault zone.
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Citation: Kim, J., Bahadori, A., & Holt, W. E. (2020, 08). Preseismic and Post-seismic Transient Strain Anomaly Patterns Before and After the 2019 Ridgecrest Earthquake Sequence . Poster Presentation at 2020 SCEC Annual Meeting.
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