BENEFITS OF SCENARIO GROUND MOTION MAPS

Earthquake hazards can be communicated with both probabilistic seismic hazard maps and ''deterministic'' maps showing estimated ground motio ns expected from a subset of the possible earthquakes. This paper desc ribes the latter class of maps as ''scenario'' ground motion maps. The principle behind the scenario maps is to portray a median estimate of ground motions from events that are reasonable, and regionally the mo st significant. The intent is that the scenario map answers the common question: ''If the fault ruptures, what do you expect?'' This paper p roposes rules for construction of scenario maps, argues that a paralle l map (a scenario probability map) should be constructed giving estima tes of the annual recurrence rates of the scenario ground motions, and compares probabilistic and scenario ground motions for areas with hig h and moderate seismic hazards. Uses for scenario maps include educati ng the public about the earthquake hazards, some engineering applicati ons and hazard response planning. (C) 1997 Elsevier Science B.V.