Engineering and Geological Effects of the July 2019 Ridgecrest Earthquake Sequence

Jonathan P. Stewart, Scott J. Brandenberg, Pengfei Wang, Chukwuebuka Nweke, Kenneth S. Hudson, Silvia Mazzoni, Yousef Bozorgnia, Kenneth W. Hudnut, Craig A. Davis, Sean K. Ahdi, Farzin Zareian, Jawad Fayaz, Rich D. Koehler, C Chupik, Ian Pierce, A Williams, Sinan O. Akciz, Martin B. Hudson, T Kishida, Benjamin A. Brooks, Ryan D. Gold, Daniel J. Ponti, Katherine M. Scharer, Devin McPhillips, T Ericksen, J Hernandez, Jason R. Patton, Brian Olson, Timothy Dawson, Jerry A. Treiman, Christopher B. DuRoss, Kelly Blake, Jeffrey L. Bachhuber, Christopher M. Madugo, J Sun, Andrea Donnellan, Gregory A. Lyzenga, Erik M. Conway, & Christine A. Goulet

Submitted August 16, 2019, SCEC Contribution #9907, 2019 SCEC Annual Meeting Poster #244 (PDF)

Poster Image: 
The Ridgecrest Earthquake sequence included a foreshock event on July 4 2019 (M6.4) and a M7.1 mainshock event on July 5 2019. These events occurred in the Eastern California Shear Zone, near Indian Wells Valley, south of China Lake and west of Searles Valley. GEER has partnered with several organizations to collect perishable data and document the important impacts of these events, including the US Geological Survey, the California Geological Survey, the US Navy, the Southern California Earthquake Center, and local utilities. Critical geotechnical features of this event are extensive left-lateral (M6.4 event) and right-lateral (M7.1 event) surface ruptures over fault segments of variable complexity and width as well as across extensional and compressive step-over zones. We also document lifeline performance at fault crossings (gas, water, electrical), mainshock slip and afterslip, liquefaction and lateral spreading features, and liquefaction effects on structures. These effects are documented using field (ground) mapping and aerial imagery that will support subsequent development of high-resolution digital elevation models. Over 1200 ground motions were recorded from the foreshock and mainshock alone, with many additional aftershock records. The data demonstrate significant impacts of site response and rupture directivity on ground motion attributes.

Key Words
earthquake response, Ridgecrest

Citation
Stewart, J. P., Brandenberg, S. J., Wang, P., Nweke, C., Hudson, K. S., Mazzoni, S., Bozorgnia, Y., Hudnut, K. W., Davis, C. A., Ahdi, S. K., Zareian, F., Fayaz, J., Koehler, R. D., Chupik, C., Pierce, I., Williams, A., Akciz, S. O., Hudson, M. B., Kishida, T., Brooks, B. A., Gold, R. D., Ponti, D. J., Scharer, K. M., McPhillips, D., Ericksen, T., Hernandez, J., Patton, J. R., Olson, B., Dawson, T., Treiman, J. A., DuRoss, C. B., Blake, K., Bachhuber, J. L., Madugo, C. M., Sun, J., Donnellan, A., Lyzenga, G. A., Conway, E. M., & Goulet, C. A. (2019, 08). Engineering and Geological Effects of the July 2019 Ridgecrest Earthquake Sequence. Poster Presentation at 2019 SCEC Annual Meeting.


Related Projects & Working Groups
Ridgecrest Earthquakes