High-Resolution Surface Wave Tomography of the Hayward Fault in the Berkeley Region Using Ambient Noise Recorded by a Dense Nodal Array
Description:
The ~70-km-long Hayward Fault (HF), capable of generating earthquakes exceeding magnitude 6, poses a critical threat to major cities in California, such as the San Francisco Bay area and Berkeley. Prior research revealed fault zone head waves near the HF, indicating a bi-material interface with distinct crustal blocks (slower P wave velocity on the eastern side). Clarifying if the entire HF is a continuous bi-material interface and obtaining a high-resolution crustal structure image surrounding the fault can greatly improve ground motion predictions in nearby urban areas.
To better understand the Berkeley section of the HF, Taira et al. (2022) deployed a 2-D dense nodal array across the campus of the UC Berkeley (UCB) and Lawrance Berkeley National Laboratory (LBNL). The dense deployment consists of 182 three-component nodal sensors with an average station spacing of ~100m and recorded continuously for about one month. Preliminary analyses of the nodal array recordings indicate the potential for reconstructing clear surface waves from the ambient noise data. In this study, we first reconstruct surface waves from ambient noise cross-correlation of each station pair. Then, Rayleigh wave group and phase velocity maps at different frequencies are constructed by inverting the picked travel times. Finally, we obtain a high-resolution shear wave velocity model for structures across the HF beneath the campus of UCB and LBNL in the top 15 km, by jointly inverting the Rayleigh wave group and phase velocities. The resolved fault zone image can improve our understanding of the HF in the Berkeley region.
Session: 3D Wavefield Simulations: From Seismic Imaging to Ground Motion Modelling [Poster Session]
Type: Poster
Date: 5/2/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Wenpei
Student Presenter: No
Invited Presentation:
Authors
Wenpei Miao Presenting Author miaowp@cea-igp.ac.cn China Earthquake Administration |
Hongrui Qiu Corresponding Author qiuhongrui@cug.edu.cn China University of Geosciences |
Lei Qin qinlei@cug.edu.cn China University of Geosciences |
|
|
|
|
|
|
High-Resolution Surface Wave Tomography of the Hayward Fault in the Berkeley Region Using Ambient Noise Recorded by a Dense Nodal Array
Category
3D Wavefield Simulations: From Seismic Imaging to Ground Motion Modelling