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Shear Wave Velocity Structure and Moho Depth Beneath the Virginia Coastal Plain (VCP) From Fundamental-mode Rayleigh-wave Group-velocity Measurements

Description: 

Deep fluid injections into the basement rock can alter its effective stress field (ss), leading to injection-induced seismic activity in the region. Monitoring induced seismicity requires a velocity model of the affected region. Given this, we investigate the crustal shear-velocity structure and estimate the Moho depth beneath the Virginia Coastal Plain (VCP) in southeastern Virginia by utilizing the fundamental-mode Rayleigh-wave group velocity and shear-wave velocity inversion. The seismic dataset is compiled using five-stations of the Hampton Roads Seismic Network (HRSN) operated by Virginia Tech between April 2022 and February 2024. We measure Rayleigh-wave group velocities of the vertical (Z-component) seismograms at periods of 6–50 s from five regional earthquakes with magnitudes between M_w 5.1 and M_w 6.2 respectively. The fundamental-mode Rayleigh-wave group velocities vary from 2.9 km/s at 6s to 3.8 km/s for 50 s period. Next, we invert these Rayleigh-wave group velocities to obtain an average 1-D shear-wave velocity-depth profile below all the five seismic stations in the array. The final resultant shear wave velocity model is a six-layer velocity model with the upper crustal velocity of 3.2 km/s, which gradually increases to 4.0 km/s for the crust-mantle boundary. The Moho depth from 1-D shear wave velocity inversion is estimated to be around ~ 35.0 km beneath the Virginia Coastal Plain.

Session: Seismology for the Energy Transition [Poster]

Type: Poster

Date: 4/16/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Mahesh

Student Presenter: No

Invited Presentation: 

Poster Number: 134

Authors