The multichannel analysis of surface wave (MASW) method, originally developed for land applications, provides shear-wave velocity (Vs) of near-surface materials (≤ 50 m). Vs is the key parameter for shear modulus, which is one of the best indicators of materials' stiffness. This is why the method has been so widely used for diverse geotechnical engineering projects on land. Thanks to the strong nature of surface waves (ground roll), data acquisition is highly effective and the subsequent data analysis becomes simple and easy, rendering it a non-expert method.

Similar applications under marine environments, however, have not become popular, at least, to the level of land applications. Main obstacles exist in the step of data acquisition that requires modifications in conventional seismic source-receiver configuration. Theories for data analysis remain unchanged as far as the shear-wave velocity (Vs) of the water-bottom layer is smaller than P-wave velocity (Vp) of water (e.g., Vs ≤ 1400 m/sec).

The general framework of the MASW method is briefly explained with a focus to wind farm applications on land. A few recent underwater applications are discussed with an emphasis on key aspects of data acquisition that led to success.

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About the presenter

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Dr. Choon Park is lead author of the MASW technique published in GEOPHYSICS in 1999. Since then, he published more than one hundred papers on MASW and related techniques. Dr. Park founded Park Seismic LLC in 2008 to provide services and Research and Development (R&D) in MASW method where he is currently working as the principal geophysicist. Since then, he has been promoting the method among relevant engineering communities by applying it in diverse geotechnical projects, including wind-turbine site surveys, soil/bedrock characterization, anomaly detection, seismic site classification, compaction evaluation, etc. Over the last one decade, Dr. Park has been providing education in MASW for civil engineers helping them practice the method on their own.

Dr. Park received his Ph.D. from the University of Kansas (KU)(1995) with the invention of swept impact seismic technique (SIST) (Geophysics, 1996) that delivers a few hundred seismic impacts in a coded mode to increase the resolution of high-frequency reflection imaging. In parallel to this, Dr. Park also started surface-wave research in the early 90s as the other low-frequency end of near-surface seismic applications, which later developed into the multichannel analysis of surface waves (MASW) method. After graduation from KU, he continued his career as a scientist at the Kansas Geological Survey (KGS), a research institute based at KU. He is the author of the first MASW data-processing software, SurfSeis, and coauthored the seismic reflection software, WinSeis and Eavesdropper, both of which were developed at KGS. Dr. Park received his master's (MS) degree from Ohio University(1988) with research in the migration of shallow high-frequency reflection data. He graduated from Seoul National University (1983) in Seoul, South Korea, with a BS in physics and science education. He was born in South Korea and lived there until he moved to the U.S. in 1985.