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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #343979
Research Project: Utilizing Acoustic and Geophysics Technology to Assess and Monitor Watersheds in the United States

Location: Watershed Physical Processes Research

Title: Measurements of soil profiles in the vadose zone using the high-frequency surface waves method

Author
item LU, ZHIQU - University Of Mississippi
item Wilson, Glenn
item SHANKLE, MARK - Mississippi State University

Submitted to: Journal of Applied Geophysics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/4/2019
Publication Date: 7/8/2019
Citation: Lu, Z., Wilson, G.V., Shankle, M. 2019. Measurements of soil profiles in the vadose zone using the high-frequency surface waves method. Journal of Applied Geophysics. 169:142-153. https://doi.org/10.1016/j.jappgeo.2019.07.002.
DOI: https://doi.org/10.1016/j.jappgeo.2019.07.002

Interpretive Summary: For exploration of unsaturated soil, a high-frequency multi-channel analysis of surface waves (HF-MASW) method has been developed. The HF-MASW method can be improved by several practical methods both in the collection and processing of the data, including (1) the self-adaptive MASW method using a sensor spacing pattern that varies along the path sampled, (2) a phase-only processing calculation, and (3) a nonlinear acoustic method with energy levels of the shear wave frequency bands dependent upon the sensor spacing. In this paper, we describe these improved techniques and apply them to process field test data that were collected over the past few years on six different soils. These soils were selected for their contrasting properties and the resulting data collection methods applied. The shear wave images of each site with three frequency band energy levels are shown and discussed. The study demonstrates the capability of the HF-MASW method to measure the soil profiles in terms of shear wave velocity, down to a depth of 2.5 meters. Practical concerns of the HF-MASW method are addressed based upon the field tests along with lessons-learned. Recommendations for data collection, analysis methods, and data processing are provided.

Technical Abstract: For soil exploration in the vadose zone, a high-frequency multi-channel analysis of surface waves (HF-MASW) method has been developed. The HF-MASW method can be enhanced by several practical techniques both in data acquisition and signal processing, including (1) the self-adaptive MASW method using a variable sensor spacing configuration, (2) a phase-only processing algorithm, and (3) a nonlinear acoustic technique with gapped frequency range excitations. In this paper, we describe these enhanced techniques and apply them to reprocess field test data that were collected over the past years on six different sites. These sites were selected for their contrasting soil properties and data acquisition configurations. The derived overtone images of each site with three frequency band excitations are shown and discussed. The study demonstrates the capability of the HF-MASW method to measure the soil profiles in terms of shear wave velocity, up to an exploration depth of 2.5 meters. Practical concerns of the HF-MASW method are addressed according to the above field tests and lessons-learned in the past. Recommendations for data acquisition, signal processing, and inversion are provided.