NEHRP Clearinghouse
- Title
- Seismic Hazard Maps for Seattle, Washington, Incorporating 3D Sedimentary Basin Effects, Nonlinear Site Response, and Rupture Directivity.
- File
- PB2008108621.pdf
- Author(s)
- Frankel, A. D.; Stephenson, W. J.; Carver, D. L.; Williams, R. A.; Odum, J. K.
- Source
- January 2007, 82 p.
- Identifying Number(s)
- USGS/OFR-2007-1175
- Abstract
- It is clear from recent seismological research that sedimentary basins strongly affect the amplitude and duration of earthquake ground motions and are responsible for certain damage patterns caused by earthquakes (Graves and others 1998; Stephenson and others, 2006). Furthermore, it has been recognized for many decades that shallow geological units such as artificial fill amplify ground shaking and that the direction of rupture propagation on a fault (directivity; see Wald and others, 1996) is an important cause of large-velocity ground-motion pulses that can damage buildings. As seismologists develop a predictive understanding of these phenomena, they can be quantitatively incorporated into probabilistic assessments of seismic hazard. In this paper we include these effects in seismic hazard maps for Seattle, Washington, which we call urban seismic hazard maps. Urban seismic hazard maps provide more spatially-detailed information about seismic hazard than the national seismic hazard maps, which use a firm-rock site condition and ground-motion relations that dont explicitly include rupture directivity (Frankel and others, 2002a). However, our urban seismic hazard maps are not site-specific maps.
- Keywords
- Damage patterns; Amplitude; Ground-motion pulses; Sedimentary basins; Seismology; Three dimensions; Seattle (Washington); Hazard maps; Duration; Earthquakes