Comparing Shear-Wave Velocity Profiles from MASW with Borehole Measurements in Unconsolidated Sediments, Fraser River Delta, B.C., Canada

Abstract

Recent field tests illustrate the accuracy and consistency of estimating near-surface shear (S) wave velocities calculated using Multi-channel Analysis of Surface Wave (MASW). To evaluate the technique in a variety of near-surface conditions and through a wide range of velocities, MASW-derived S-wave velocity profiles (S-wave velocity vs. depth) were statistically compared to S-wave velocity profiles measured in seven boreholes in the unconsolidated sediments of the Fraser River delta, near Vancouver, B.C., Canada. An overall difference of approximately 15 percent was observed between these two uniquely determined sets of S-wave velocities from the seven well locations. A blind test of the standalone accuracy of MASW was conducted at an eighth well. For this blind test, S-wave velocity measurements made in and interpreted from the borehole were not made available during MASW data processing. Differences between S-wave velocities using MASW from those measured in the blind test borehole averaged nine percent. No systematic differences between these results were observed in data from any of the eight test sites. The MASW method provided reliable S-wave velocity profiles from [Formula: see text] below the ground surface at some sites in the Fraser delta.

The Selection of Field Acquisition Parameters for Dispersion Images from Multichannel Surface Wave Data

“…By using an array of receivers, multimodal dispersion curves from a MASW survey are presented in the form of energy bands to form a dispersion spectral image. XIA et al (2000a) demonstrated that the fundamental-mode phase velocities obtained through a MASW study generally provide reliable estimates of the shear-wave velocities (Vs). The method has been employed in various applications in engineering geology (e.g., MILLER et al, 1999a,b;PARK et al, 1998PARK et al, , 1999bPARK et al, , 2000XIA et al, 1998XIA et al, , 1999XIA et al, , 2000a.…”

Comparing Shear-Wave Velocity Determined by MASW with Borehole Measurement at Merapi Sediment in Yogyakarta

“…The results are represented in the form of average relative differences in all layers of soil. The average relative difference describes the overall differences between shearwave velocities from the MASW method and the empirical borehole method (Xia et al, 2000). These results are shown in Table 3.…”

Using Surface Wave Method to Define a Sinkhole Impact Area in a Noisy Environment

“…Based on their experience, the fundamental-mode phase velocities, when calculated with high accuracy (e.g., Xia et al, 2000b), can generally provide reliable S-wave velocities (±15%). The accuracy can be increased if higher modes of surface waves are available and included in the inversion process (Xia et al, 2000a).…”

“…The accuracy can be increased if higher modes of surface waves are available and included in the inversion process (Xia et al, 2000a). Recent advances in the use of surface waves for near-surface imaging incorporated Multichannel Analysis of Surface Waves (MASW) (Park et al, 1996(Park et al, , 1999a(Park et al, , and 1999bXia et al, 1997Xia et al, , 1999Xia et al, , and 2000b) with a standard common depth point (CDP) roll-along acquisition format (Mayne, 1962) similar to conventional petroleum exploration data acquisition. Combining these two uniquely different approaches to acoustic imaging of the subsurface allows high confidence, non-invasive delineation of horizontal and vertical variations in near-surface material properties , Xia et al, 2000c.…”