The Fine‐Scale Structure of Long Beach, California, and Its Impact on Ground Motion Acceleration

The metropolitan Los Angeles region represents a zone of high-seismic risk due to its proximity several fault systems, including the San Andreas fault. Adding this problem is fact that and surrounding cities are built on top soft sediments tend trap amplify seismic waves generated by earthquakes. In study, we use three dense petroleum industry surveys deployed in 16 × 16-km area at Long Beach, California, produce high-resolution model kilometer crust investigate influence structural variations amplification waves. Our velocity estimates reveal substantial lateral contrasts correlate remarkably well with geological background area, illuminating features such as Newport-Inglewood fault, Silverado aquifer, Gabriel river. We then computational modeling show presence these small-scale structures have clear impact intensity expected shaking, can cause ground-motion motion acceleration change factors over subkilometer horizontal scale. These results shed light onto scale be type tectonic settings highlight importance resolution modern-day hazard estimates.