Combined Use of Active and Passive Surface-wave Techniques for Cost-effective UBC/IBC Site Classification
Association of Environmental and Engineering Geologists, Conference Proceedings, 2005 Annual Meeting
Antony J. Martin, Jonathan B. Shawver*, and John G. Diehl, GEOVision Geophysical Services, Corona, California
Paper – [pdf] INFR_2005 AEG -Martin Shawver Diehl Combined use of Active&Passive
The average shear wave velocity of the upper 30m (VS30) and upper 100ft (VS100) are used in the 2001 Uniform Building Code (UBC) and the 2000 International Buiding Code (IBC), respectively, to separate sites into classes for earthquake engineering design. Many state and local building codes are based on either the UBC or IBC. Commonly used geophysical techniques for estimating VS30/VS100 require a borehole. Active and passive surface wave techniques do not require a borehole, and offer a cost effective means of estimating VS30 or VS100. Further, while they do not have the resolution of borehole techniques,
they sample a much larger volume of earth and may, therefore, provide a more representative estimate of average shear wave velocity. The combined use of active and passive surface wave techniques in urban areas can reduce the need for costly energy sources such as bulldozers, electromechanical shakers and large weight drops. Case histories from several sites with borehole velocity control in California and Nevada demonstrate the effectiveness of surface wave techniques for estimating VS30/VS100 in a variety of geologic conditions.