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International Journal of Geophysics
Volume 2016, Article ID 9305095, 11 pages
Research Article

Estimate for Southwest China

1Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China
2Pacific Engineering and Analysis, 856 Sea View Drive, El Cerrito, CA 94530, USA
3Institute of Geophysics, China Earthquake Administration, Beijing 100081, China

Received 26 September 2015; Accepted 7 February 2016

Academic Editor: Marek Grad

Copyright © 2016 Yan Yu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Several methods were used to estimate from site profiles with borehole depths of about 20 m for the strong-motion stations located in Southwest China. The methods implemented include extrapolation (constant and gradient), Geomatrix Site Classification correlation with shear-wave velocity, and remote sensing (terrain and topography). The gradient extrapolation is the preferred choice of this study for sites with shear-wave velocity profile data. However, it is noted that the coefficients derived from the California data set are not applicable to sites in Southwest China. Due to the scarcity of borehole profiles data with depth of more than 30 m in Southwest China, 73 Kiknet profiles were used to generate new coefficients for gradient extrapolation. Fortunately, these coefficients provide a reasonable estimate of for sites in Southwest China. This study showed could be estimated by the time-average shear-wave velocity (average slowness) of only 10 meters of depth. Furthermore, a median estimate based upon Geomatrix Classification is derived from the results of the gradient extrapolation using a regional calibration of the Geomatrix Classification with . The results of this study can be applied to assign to the sites without borehole data in Southwest China.