Serving professionals in engineering, environmental, and groundwater geology
since 1957

JUNE MEETING NOTICE
***Tuesday, June 10th***
Download June Newsletter

Topic: Application of Surface and Borehole Shear Wave Geophysical Techniques to Engineering Investigations


Speakers: Antony Martin, P.GP., Technical Director, GEOVision Geophysical Services, Corona, California

Location: Pizza Cookery:
6029 Topanga Canyon Blvd. Woodland Hills, CA 91367.
Map is on Page 9.

Time: 6:00 p.m.-Social Hour; 7:00 p.m.-Dinner; 7:45 p.m.-Presentation

Cost: $30 per person with reservations, $35 without reservations, $15 with a valid Student ID. Pizza and Beer!

Reservations: Please e-mail Peter Thams at thams.peter@gmail.com


Abstract:
Surface and borehole geophysical techniques can be used to obtain shear (S) wave velocity depth profiles. Surface geophysical methods include the active surface wave (spectral analysis of surface waves and multi-channel analysis of surface waves) and passive surface wave (array and refraction microtremor) techniques. Borehole techniques include the PS suspension logging, downhole seismic, cross hole seismic and seismic cone methods. A common application of these methods is to determine the average S-wave velocity of the upper 30m or 100ft (VS30) for UBC/IBC site classification for seismic design. Many state and local building codes are based on either the UBC or IBC. These techniques are also used to generate S-wave velocity models for site response modeling and liquefaction analysis.

Other geophysical methods than can involve the measurement of S-waves include the seismic refraction and reflection methods. S-wave refraction surveys are more difficult to implement that the P-wave counterpart but are useful to map shallow sedimentary rock when overlying sediments are saturated. S-wave seismic reflection surveys can image to shallower depth and with better resolution than P-wave surveys and are useful for shallow fault imaging.

Case histories will be presented demonstrating the application of S-wave techniques to near surface geophysical investigations.
 
Speaker:
Mr. Martin received his B.Sc. in Geophysics from the University of British Columbia, British Columbia, Canada in 1985 and M.S. in Geology (Geophysics Option) from California State University, Long Beach in 1999. Since 1995, Mr. Martin has been the Technical Director of GEOVision Geophysical Services where he manages surface and borehole geophysical investigations applied to engineering, environmental and groundwater projects. From 1987 to 1995, Mr. Martin was employed by IT Corporation where he became the Manager of the Geophysics Group. Between 1980 and 1987, Mr. Martin was employed as an engineering technician and geologist at Earth Technology Corporation.