NEHRP Clearinghouse
- Title
- Shear-Wave Velocity of the Ground Near Sixty California Strong Motion Recording Sites by the Spectral Analysis of Surface Waves (SASW) Method and Harmonic-Wave Sources.
- File
- PB2006105330.pdf
- Author(s)
- Kayen, R.; Thompson, E.; Minasian, D.; Carkin, B.
- Source
- January 2005, 136 p.
- Identifying Number(s)
- USGS/OFR-2005-1366
- Abstract
- We investigate sixty strong motion recording (SMR) sites using an active-source approach that employs ultra-low frequency-controlled harmonic waves to measure the dispersive nature of surface waves in the ground. An inversion algorithm employing a non-linear least-squares best fit is used to invert shear-wave velocities for the upper 30 meters of the soil column. The overall objective of this project is to visit unclassified California strong motion recording (SMR) sites and acquire spectral analysis of surface waves (SASW) data to characterize the site stiffness properties to a minimum depth of 30 meters. The principal products of this effort are the computation of shear-wave velocity logs, Vs-30 site values, and NEHRP site classification. This study was conducted at the request of the Pacific Earthquake Engineering Research (PEER) Center, Lifelines Program Task 1L10 to provide a quantitative basis for site classification of ground associated with recorded ground motions used in the Next Generation Attenuation (NGA) modeling project. Our preliminary findings were delivered in digital format on January 30, 2004 to PEER-NGA project participants through a password protected FTP site.
- Keywords
- Ultra-low; Surface waves; California; Frequency controlled; Shear-wave velocity; Active-source approachs; Harmonic wave sources; Spectral analysis of surface waves (SASW); Strong motion recording (SMR) sites; Dispersive nature