NEHRP Clearinghouse
- Title
- Quantifying and Qualifying USGS ShakeMap Uncertainty.
- File
- PB2009109241.pdf
- Author(s)
- Wald, D. J.; Lin, K. W.; Quitoriano, V.
- Source
- January 2008, 29 p.
- Identifying Number(s)
- USGS-OFR-2008-1238
- Abstract
- We describe algorithms for quantifying and qualifying uncertainties associated with USGS ShakeMap ground motions. The uncertainty values computed consist of latitude/longitude grid-based multiplicative factors that scale the standard deviation associated with the ground motion prediction equation (GMPE) used within the ShakeMap algorithm for estimating ground motions. The resulting grid-based 'uncertainty map' is essential for evaluation of losses derived using ShakeMaps as the hazard input. For ShakeMap, ground motion uncertainty at any point is dominated by two main factors: (i) the influence of any proximal ground motion observations, and (ii) the uncertainty of estimating ground motions from the GMPE, most notably, elevated uncertainty due to initial, unconstrained source rupture geometry.
- Keywords
- Mapping; Qualitative uncertainty assignments; ShakeMaps; U.S. Geological Survey; Algorithms; Observations; Earthquakes; Ground motion estimation; Fault rupture geometry; Computer software; Event selections; Maps; Foreign countries; Quantitative shaking uncertainty calculations