Technical Talk Abstract



Multichannel Analysis of Surface Waves

Doug Crice, Geostuff

Geostuff

dcrice@geostuff.com

Multichannel Analysis of Surface Waves is the most recent development in seismic exploration for engineering geophysics. It is able to create vertical plots of shear wave velocities and cross section plots of shear wave velocities in the subsurface. Of course, shear wave velocities are important because they are a direct measurement of the shear strength of materials, and as such, provide information the engineering geologist can use to estimate the bearing capacity. Another advantage is that they can provide a continuous display between SPT and borehole surveys. In fact, some argue that they should perhaps be used in advance to plan a drilling program, particularly when the subsurface may be non-uniform. The talk will explain the basic science of MASW, followed by several case histories.

Speaker Bio

Doug Crice, has been a witness to the evolution of seismic surveys for engineering applications for over 50 years. As an instrument designer, he contributed to some elegant products that enhanced their capabilities in shallow seismic exploration. He received the Hal Mooney Award from the Society of Exploration Geophysics for his contributions, unusual for an equipment manufacturer. As part of the process, he has followed closely, as well as facilitated, many of these developments from rudimentary refraction surveys, borehole shear wave surveys, shallow reflection surveys, and now Multichannel Analysis of Surface Waves. He is the author of the definitive paper on borehole shear wave surveys, and some survey articles on MASW.

He started in geophysics conducting Geodimeter Fault Movement in California as an engineering technician at the Department of Water Resources, writing Bulletin 116-2 on the results. He received his BSEE from Sacramento State University in 1971 and started at Nimbus Instruments as President and chief engineer. Nimbus was sold to Geometrics Inc in 1978 where he became Vice President of Marketing, becoming hopelessly obsolete as an electrical engineer, but using his knowledge of electronics and geophysics to direct further developments. He had forays in startups in ground penetrating radar and founded Wireless Seismic Inc, a distributed wireless acquisition system for oil and gas exploration. He is now owner of a small company, Geostuff, www.geostuff.com which produces accessories for seismic exploration.