We estimated three-dimensional (3D) deep S-wave velocity (Vs) model of the South San Francisco Bay Area using three-component (3C) microtremor measurements and microtremor array measurements (MAM). Data acquisition included single station 3C microtremor measurements at approximately 80 sites and MAM at approximately 10 sites. The 3C microtremor measurements yielded horizontal to vertical spectral ratio (H/V) and the microtremor array measurements yielded Vs profiles. We compiled all H/V and Vs profiles and estimated an approximate 3D Vs model to a depth of 3000 m. Depth to bedrock of Vs = 2000 m/s is the deepest (> 2000 m) to the Southwest (Cupertino) and northeast (San Jose - Milpitas) of downtown San Jose. The peak frequency of H/V is less than 0.2 Hz in this region. Bedrock depth appears to be relatively shallow (700 to 1500 m) in the middle of the South Bay, from downtown San Jose to San Jose Airport and Alviso. The peak frequency of H/V ranged from 0.3 to 2.0 Hz in the region. This high-velocity ridge in the South Bay appears parallel to the Silver Creek Fault and may continue west to Mountain View.
Presentation Date: Monday, October 12, 2020
Session Start Time: 1:50 PM
Presentation Time: 1:50 PM
Location: 351D
Presentation Type: Oral
