Full text loading...
-
Near-surface Velocity Structure Modeling by Joint Inversion of Microtremor and Active Surface Wave Survey Data
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 6th Asia Pacific Meeting on Near Surface Geoscience and Engineering, May 2024, Volume 2024, p.1 - 6
Abstract
Summary
We propose a new idea to make a velocity structure model for the near surface down to 60 m by joint inversion analysis of horizontal-to-vertical spectral ratio (HVSR) with shot data obtained by small-sized active surface wave survey (SASW). Mode of occurrence is focused on P-wave refractions/reflections, SV-wave reflections occur in so-called “noise cone”, as well as surface waves. Conventionally, an estimated 1-D Vs model has been verified weather a calculated HVSR and dispersion curve matches with observed ones. However, it is difficult to estimate an appropriate Vs model only from HVSR data. Ambiguity of Vs model still remains in the inversion from a dispersion curve obtained by microtremor array measurements (MAM). Characteristic feature of our idea is to append one more step to validate a 1-D velocity model. A shot gather waveform is synthesized by using discrete wave-number method (DWM) and validates the model by correlating traveltimes not only surface waves but also P- and SV-waves on an actual shot record. The proposed method can give narrow constraints to a near-surface velocity model including P-waves. We applied the method to the data measured in Kanto Plain, Japan, and could successfully estimate velocity structure of the near surfaces.
© EAGE Publications BV