Ten-year probability of strong earthquakes on major faults in boundaries of active blocks in Chinese continent

Seismogenic environment in Chinese continent is layered vertically and partitioned horizontally. The boundaries of active blocks controlled strong earthquakes in Chinese continent. 10-year quantitative study on earthquake risk of the major faults in boundaries of active blocks is significant for seismic fortification. Based on the samples of elapse rate from different regions, recurrence model of strong earthquakes in Chinese continent is established, and the probability of strong earthquakes in each fault segment is obtained. Due to the vast territory of Chinese continent, data of various faults have unbalanced quality, and earthquake probability of several faults cannot be obtained due to insufficient data. Therefore, this paper uses different methods to supplement the relevant data. For segments lacking record of recurrence interval of strong earthquakes, the recurrence interval is calculated by empirical relationship between the slip rate and the recurrence interval using the slip rate from geological or geodetic data; for segments lacking record of date of last strong earthquake, the distribution of elapse time is given according to the complete time of earthquake catalogue. Based on this, we obtained cumulative probability and conditional probability of strong earthquakes of 391 fault segments of major faults in boundaries of active blocks in the next 10 years. Since the duration of forecasting period has great influence on conditional probability, and the recurrence interval of strong earthquakes in various segment is quite different, analysis of risk of strong earthquakes mainly based on cumulative probability. The result show that the segments with high risk of strong earthquakes in the next 10 years are mainly concentrated in the east boundary of Sichuan-Yunnan Block, the northeast edge of Tibetan Plateau, the east and northwest boundaries of Ordos Block, Tianshan mountain and Himalayan arc.