SEISMIC HAZARD RESULTING FROM AFTERSHOCK ACTIVITY FOLLOWING A CASCADIA SUBDUCTION EARTHQUAKE
Great (M>8.0) subduction interface earthquakes, or megathrust earthquakes, are typically followed by hundreds or even thousands of aftershocks, several of which may have magnitudes exceeding M7.0. While the seismic hazard resulting from a Cascadia megathrust earthquake is well recognized and discussed, little attention has been given to quantifying the subsequent aftershock activity and its potential impact on communities in the region. The probability of the next Cascadia megathrust earthquake occurring within the next 100 years is estimated to be 17 percent. Based on an analysis of recorded aftershock sequences at Cascadia-like subduction zones, this paper offers preliminary estimates of ground shaking probabilities resulting from Cascadia megathrust earthquake aftershocks for 22 communities in southwestern British Columbia, Canada and the Pacific Northwest, USA. Calculations estimate the likelihood of an aftershock exceeding each of three intensity levels (MMI V widely felt; MMI VI-threshold for non-structural damage; and, MMI VII threshold of structural damage). Results presented in this paper are intended to enable community officials and the general public to better understand the Cascadia earthquake threat and to encourage a more comprehensive discussion of the next great Cascadia megathrust event.
Aftershocks subduction earthquakes ground shaking probabilities Cascadia
M.R. SEEMANN T. ONUR J.F. CASSIDY
Department of Geography, University of Victoria, Victoria, BC, Canada Risk Management Solutions, Inc., Newark, CA, USA. Geological Survey of Canada, Natural Resources Canada, Sidney, BC, Canada.
国际会议
14th World Conference on Earthquake Engineering(第十四届国际地震工程会议)
北京
英文
2008-10-12（万方平台首次上网日期，不代表论文的发表时间）