ACTIVE TECTONICS AND SEISMICITY IN INTRACONTINENTAL CHINA: A REVIEW

Mainland China and the surrounding regions show widespread intracontinental deformation and seismicity, their spatial patterns are generally consistent with known lithospheric heterogeneities and Cenozoic tectonics. In western China (west of 105 degree longitude), the Indo-Asian collision causes crustal compression across the Tibetan Plateau and the Tian Shan mountain belt, with the stable Tarim Basin in between. In contrast, eastern China is marked by low present-day strain rates and distributed extension. Seismicity is generally consistent with present-day strain rates. In North China, where the earthquake records extend for more than 2000 years, the spatial distribution of total seismic moment release is comparable to that of the present-day strain rates. However, this comparison breaks down when using smaller time windows. Numerous damaging earthquakes since the past century occurred in regions of relatively low strain rates, and the Chinese catalog shows that, over the past 2000 years, large earthquakes roamed between widespread fault systems such that no M>7.0 events ruptured twice the same fault segment. These earthquakes caution the use of present-day strain rates to forecast intracontinental earthquakes, and challenge the practice of assessing earthquake hazards that relies heavily on existing earthquake records.