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Shear Wave Velocity Profiling in Urban Areas Using Micro-array Microtremor HVSR Inversion and SPAC Method

Description: 

The magnitude of ground motions is significantly influenced by the shear wave velocity (V_S) profile of the site. Thus, estimating accurate V_S profile is required to better understand the seismic hazard and eventually to minimize potential earthquake damage. However, in urban areas, V_S data have not often been measured or have been lost. Due to environmental constraints such as limited space, traffic, and densely packed buildings, it is difficult to perform additional borehole-based geophysical surveys. Alternatively, noninvasive measurement techniques conducting in confined spaces can help to detect V_S profiles. This study aims to evaluate the applicability of a method that integrates the microtremor horizontal to vertical spectral ratio (mHVSR) and micro-array spatial autocorrelation (mSPAC) techniques for measuring V_S profiles in urban environments. Using micro arrays of geophones with a radius of less than 2 meters, microtremor data were collected. Then, shallow V_S profiles were obtained through phase velocity analysis with SPAC technique, and deep V_S profiles were derived using the HVSR technique. Two results were then combined to produce continuous V_S profiles. The derived V_S profiles were validated using in-situ borehole data. Additionally, azimuthal HVSR analysis was conducted to identify the optimal array geometry that minimizes distortions caused by artificial structures and topographical effects.

Session: New Directions in Environmental, Seismic Hazard and Mineral Resource Exploration Studies [Poster]

Type: Poster

Date: 4/17/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Jongwon

Student Presenter: Yes

Invited Presentation: 

Poster Number: 114

Authors