Hazard Estimate Of Strong Earthquake In Potential Seismic Tsunami Source And Its Applation In Tsunami Risk Analysis

Seismic tsunami hazard analysis is one of the hot spots in the current tsunamis research.Hazard estimate of strong earthquake in potential seismic tsunami source, being the basis of seismic tsunami hazard analysis, includes two aspects: estimate of the upper bound earthquake magnitude and the return level of strong earthquake. Chinese southeast coastal areas have the risk of the seismic tsunami, so it is necessary to estimate the hazard of strong earthquake in the seismic tsunami sources in Chinese nearshore and its adjacent areas. These estimation results can be referenced by making evacuation plan and engineering criterion.What we discuss in this paper includes three aspects: estimation of the risk of strong earthquake, uncertainty analysis of estimation results and its application in tsunami risk analysis.(1) Estimation of the hazard of strong earthquake: We discuss previous study of the upper bound earthquake magnitude and apply the Generalized extreme value theory to estimate the upper bound earthquake magnitude and the return level of strong earthquake. We consider the quiet and active period in choosing the time interval and consider the regional geological tectonic feature in identifying the potential seismic tsunami source area. we discuss the uncertainty of strong earthquake upper bound magnitude estimation and the return level estimation of strong earthquake, getting their confidence interval under a certain confidence level.(2) Selection of the case study area and estimation of parameters: Identifying Ryukyu trench subduction zone(22°N-32.5°N,120.5°E-133°E)as the case study area. We use the seismic data of USGS and analysis the activity of earthquake and get the period. According to the results, wechoose the sample of the largest magnitude to estimate the parameters, at the last we fit and diagnose the model we have chosen and get the confidence interval under the confidence level.We get the confidence interval of Upper bound earthquake magnitude and under the 95%confidence level is 8.4±0.37, the return level of strong earthquake during 30years、50 years and100 years is 7.8?0.54、8.0?0.48、8.1±0.42.(3) Tsunami simulation: According to the earthquake magnitude estimate results, we carry out the tsunami simulation by COMCOT model and get the maximum tsunami wave height of site-specific,and draw the curve of tsunami wave height.