The Wilmington Blind-Thrust Fault: An active, concealed earthquake source beneath Los Angeles, CA

Franklin D. Wolfe, John H. Shaw, Andreas Plesch, Daniel J. Ponti, James F. Dolan, & Mark R. Legg

Published July 27, 2018, SCEC Contribution #8213, 2018 SCEC Annual Meeting Poster #250

Analysis of 2D and 3D offshore seismic reflection profiles, petroleum and water wells, and recent mapping of groundwater aquifers in the southwestern Los Angeles basin indicate that the Wilmington blind-thrust fault is tectonically active and capable of generating large, damaging earthquakes. This overturns the long-held view that the fault became dormant in the Late Pliocene, barring its inclusion in state-of-the-art regional earthquake hazard assessments. The size of the fault suggests that it is capable of generating moderate-magnitude earthquakes (M 6.2-6.3), while potential linkages with other nearby faults (e.g., Huntington Beach, Torrance, Compton) pose the threat of larger, multi-segment events (M > 7). These earthquakes would directly impact the Ports of Los Angeles and Long Beach, as well as the broader Los Angeles metropolitan area.

Key Words
blind-thrust, fault, Wilmington, Los Angeles, California, active

Citation
Wolfe, F. D., Shaw, J. H., Plesch, A., Ponti, D. J., Dolan, J. F., & Legg, M. R. (2018, 07). The Wilmington Blind-Thrust Fault: An active, concealed earthquake source beneath Los Angeles, CA. Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Geology