SEISMIC RISK QUANTITATIVE EVALUATION ON BLIND FAULTS IN TIANJIN AREA

Based on faults surveying and research data in Tianjin area,through studying tectonic structure,Quaternary activity,deep structure,stress and strain fields and seismicity on the Tianjin Fault,the activity and tectonic features of the fault are determined synthetically.Using seismo-geological data,and the historical and moderm seismicity data,the frequency-magnitude relationship model reckoning by 500years is established and the relationship between the upper limit of maximum magnitude Mmu and at/b is fit,which is applied to evaluating potential earthquake's maximum magnitude on moderately and weakly active blind faults in the fault sub-areas of the region.Then Poisson probability model is adopted and quantitative parameters such as the maximum magnitude,occurrence probability,recurrence period of the south Tianjin Fault in the coming 50～200years are calculated.