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A global hybrid VS30 map with a topographic slope–based default and regional map insets

David C. Heath·David J. Wald·C. Bruce Worden·Eric M. Thompson·Gregory M. Smoczyk
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Abstract

Time-averaged shear wave velocity over the upper 30 m of the earth’s surface ( V S 30 ) is a key parameter for estimating ground motion amplification as both a predictive and a diagnostic tool for earthquake hazards. The first-order approximation of V S 30 is commonly obtained through a topographic slope–based or terrain proxy due to the widely available nature of digital elevation models. However, better-constrained V S 30 maps have been developed in many regions. Such maps preferentially employ various combinations of V S 30 measurements, higher-resolution elevation models, lithologic, geologic, geomorphic, and other proxies and often utilize refined interpolation schemes. We develop a new hybrid global V S 30 map database that defaults to the global slope-based V S 30 map, but smoothly inserts regional V S 30 maps where available. In addition, we present comparisons of the default slope-based proxy maps against the new hybrid version in terms of V S 30 and amplification ratio maps, and uncertainties in assigned V S 30 values.

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90° N90° S · 180° W ← longitude → 180° E
Source-reported bounding extent: 21.37124437061831° to 48.8936153614802° latitude; -127.35351562499999° to -90.52734374999999° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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David C. Heath, David J. Wald, C. Bruce Worden, Eric M. Thompson, Gregory M. Smoczyk. 2020-06-09. A global hybrid VS30 map with a topographic slope–based default and regional map insets. https://doi.org/10.1177/8755293020911137

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