Assessing the Influence of Characteristic Landforms, Landscape Positions, and Geology on VS30 Estimation
Abstract
The time-averaged shear-wave velocity (VS) of the top 30 meters, also known as VS30, is an important measurement for representing subsurface material properties that is used by engineers for seismic hazard assessments. Because measuring in-situ VS30 values require using geophysical methods that can be cost- and/or environmentally-prohibitive, proxy-based methods using geologic and geomorphic information have been applied to estimate VS30 values in areas without actual measurements. A recent study by Lin et al. (2019) showed that the empirical relationships between VS30 and topographic attributes (e.g., slope, local relief) vary depending on the measurement length scales of topographic attributes, resolution of the digital elevation model (DEM), and different geologic groups. In this study, we examine relationships between VS30 and topographic attributes and how they differ depending on length scales of characteristic landforms, landscape positions, and different geologic groups, by focusing on areas with dense VS30 measurements, such as Japan and Taiwan. We convolve the DEMs by using either a smoothing window or a local relief window with various length scales of radii ranging from 100 to 2500 meters. Then, we examine the correlation between VS30 and various geomorphic metrics considering the length scales of characteristic landforms, their positions, and geologic groups. Our analyses have the potential to provide a better understanding about the relationships between topographic metrics and VS30, which may be affected by surface processes and tectonics.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMNS43D0863K
- Keywords:
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- 0994 Instruments and techniques;
- EXPLORATION GEOPHYSICS;
- 0999 General or miscellaneous;
- EXPLORATION GEOPHYSICS;
- 1835 Hydrogeophysics;
- HYDROLOGY