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A terrain-based site characterization map of California with implications for the contiguous United States

Bulletin of the Seismological Society of America

By:
, , ,
DOI: 10.1785/​0120100262

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Abstract

We present an approach based on geomorphometry to predict material properties and characterize site conditions using the VS30 parameter (time‐averaged shear‐wave velocity to a depth of 30 m). Our framework consists of an automated terrain classification scheme based on taxonomic criteria (slope gradient, local convexity, and surface texture) that systematically identifies 16 terrain types from 1‐km spatial resolution (30 arcsec) Shuttle Radar Topography Mission digital elevation models (SRTM DEMs). Using 853 VS30 values from California, we apply a simulation‐based statistical method to determine the mean VS30 for each terrain type in California. We then compare the VS30 values with models based on individual proxies, such as mapped surface geology and topographic slope, and show that our systematic terrain‐based approach consistently performs better than semiempirical estimates based on individual proxies. To further evaluate our model, we apply our California‐based estimates to terrains of the contiguous United States. Comparisons of our estimates with 325 VS30 measurements outside of California, as well as estimates based on the topographic slope model, indicate our method to be statistically robust and more accurate. Our approach thus provides an objective and robust method for extending estimates of VS30 for regions where in situ measurements are sparse or not readily available.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
A terrain-based site characterization map of California with implications for the contiguous United States
Series title:
Bulletin of the Seismological Society of America
DOI:
10.1785/​0120100262
Volume
102
Issue:
1
Year Published:
2012
Language:
English
Publisher:
GeoScienceWorld
Contributing office(s):
Earthquake Science Center
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
114
Last page:
128
Country:
United States
State:
California