EGU23-15261, updated on 26 Feb 2023
https://doi.org/10.5194/egusphere-egu23-15261
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Adjoint-State Traveltime Tomography of Long Valley Caldera in California

Chun Fei Chey1, Tianjue Li2, and Ping Tong3
Chun Fei Chey et al.
  • 1Nanyang Technological University, School of Physical and Mathematical Sciences, Mathematical Sciences, Singapore, Singapore (chey0014@e.ntu.edu.sg)
  • 2Nanyang Technological University, School of Physical and Mathematical Sciences, Mathematical Sciences, Singapore, Singapore (tianjue001@e.ntu.edu.sg)
  • 3Nanyang Technological University, School of Physical and Mathematical Sciences, Mathematical Sciences, Singapore, Singapore (tongping@ntu.edu.sg)

Long Valley Caldera is a depression located in eastern California, which is the Earth’s largest caldera. Geological structures beneath Long Valley Caldera are mapped by the novel adjoint-state traveltime tomography method. Adjoint-state traveltime tomography is an Eikonal equation-based seismic imaging method. It is computationally efficient as compared to wave equation-based adjoint tomography methods. Furthermore, the method avoids ray tracing in non-homogeneous media, which may fail using conventional ray tracing techniques. The data used in the method include P- and S-wave arrival times gathered from Northern California Earthquake Data Center (NCEDC). P-wave traveltimes are directly obtained from NCEDC, while high-quality S-wave arrivals are carefully picked on raw seismograms based on waveform similarity. With the abundant seismic traveltime data and adjoint-state traveltime tomography method, we can generate high-resolution P- and S-wave velocity models for the region of Long Valley Caldera. The relationship between velocity heterogeneity and seismic and magmatic activities will be investigated.   

How to cite: Chey, C. F., Li, T., and Tong, P.: Adjoint-State Traveltime Tomography of Long Valley Caldera in California, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15261, https://doi.org/10.5194/egusphere-egu23-15261, 2023.