Targeted High-Resolution Topographic Imaging of Active Faults and the Ridgecrest Earthquake Sequence Ruptures in Southern California

Andrea Donnellan, Gregory A. Lyzenga, Jay W. Parker, Adnan Ansar, Christine A. Goulet, Yehuda Ben-Zion, Frank L. Vernon, & David K. Lynch

Published August 15, 2019, SCEC Contribution #9834, 2019 SCEC Annual Meeting Poster #229 (PDF)

We discuss observations from UAVSAR, small inhabited areal systems (sUAS or drones), and continuous camera streams over active faults, the moving Mundo Mudpot, and the Ridgecrest earthquake sequence ruptures in southern California. We have targeted 1) the seismically active San Jacinto fault and 2) the creeping southernmost San Andreas fault at Painted Canyon, and 3) the M6.4 and M7.1 ruptures of the Ridgecrest earthquake sequence just south of Highway 178. In general, we cover about 0.3 km2 with the sUAS, while the UAVSAR is large scale by nature. UAVSAR observations indicate that the San Jacinto fault is locked and that the southern San Andreas shows creep on the order of a few cm. We also have a continuously operating camera pointed at the Sage brush Flats site at the San Jacinto fault near Anza. Pre- and post-Ridgecrest sequence image comparisons show subpixel changes at the 30% level with larger changes in strands of the fault zone than the surrounding material, suggesting that the fault damage zone is more susceptible to disruption from shaking and environmental effects than the surrounding rocks. UAVSAR observations show co- and post-seismic creep on the Coachella section of the San Andreas fault in association with the El Mayor – Cucapah earthquake. The fault also crept in association with the recent Ridgecrest earthquake sequence. We continue to observe the fault with UAVSAR and structure from motion (SfM) measurements performed with sUAS and will analyze the data for fault creep from the recent event. We present repeat post-seismic imaging collected at the recent M6.4 and M7.1 ruptures to understand the amount of localized post-seismic deformation and to clarify whether the motion occurs continuously or episodically. Lastly, we are repeatedly observing the moving Mundo Mudpot east of the Salton Sea, with the goal of placing its behavior within a regional tectonic context.

Key Words
Ridgecrest, earthquake, San Andreas fault, San Jacinto Fault, UAVSAR, SfM, Creep

Citation
Donnellan, A., Lyzenga, G. A., Parker, J. W., Ansar, A., Goulet, C. A., Ben-Zion, Y., Vernon, F. L., & Lynch, D. K. (2019, 08). Targeted High-Resolution Topographic Imaging of Active Faults and the Ridgecrest Earthquake Sequence Ruptures in Southern California. Poster Presentation at 2019 SCEC Annual Meeting.

Related Projects & Working Groups
Ridgecrest Earthquakes