Detection of a fracture zone using microtremor array measurement

Abstract

We have conducted microtremor array measurements to estimate shallow S-wave velocity ([Formula: see text]) structures at two sites (the 921 Earthquake Museum of Taiwan and the Taiwan Provincial Consultative Council) located near surface ruptures of the Chelungpu Fault. Ten stations, consisting of three different-aperture triangles and a central station, are adopted for each array deployment. Using the array data, we calculate dispersion curves of Rayleigh waves using the frequency-wavenumber spectrum method and then estimate [Formula: see text] structures by the surface-wave inversion technique. The obtained 2D [Formula: see text] profiles could clearly show compressive and flexural deformation structures with the surface ruptures located at relatively weak (low [Formula: see text]) zones. This indicates compressive buckling as the most likely mechanism for surface rupturing along these low [Formula: see text] zones. Importantly, this study successfully depicts strata disturbances in a fault fracture zone using microtremor array measurements and forward numerical modeling of trishear fault-propagation folds.

Frequency-Bessel Transform Based Microtremor Survey Method and Its Engineering Application

“…The dispersion curve is then inverted to obtain the S-wave velocity structure of the subsurface media, which serves the exploration objective [ 1 ]. The detection of buried faults [ 4 , 5 , 6 ], underground boulders [ 7 ], the soil–rock interface [ 8 , 9 , 10 ], goaf [ 11 ], and landslide mass structures [ 12 , 13 ] are a few of the engineering issues that have been successfully solved using the microtremor survey method in recent years.…”

Estimation of Shear-Wave Velocity Structures in Taichung, Taiwan, Using Array Measurements of Microtremors

“…In terms of economical and practical considerations, microtremor array measurements provide a favorable alternative in estimating S-wave velocity structures. Many studies have employed microtremor array measurements to examine material properties [3][4][5][6][7][8][9][10][11][12][13][14]. Singh et al [15] estimated the site characteristics of different geological formations in the Kachchh seismic zone of western India by conducting microtremor array measurements at 7 sites and single-station microtremor measurements at 36 sites.…”