Active faulting and tectonics in China

Abstract

We present a study of the active tectonics of China based on an interpretation of Landsat (satellite) imagery and supplemented with seismic data. Several important fault systems can be identified, and most are located in regions of high historical seismicity. We deduce the type and sense of faulting from adjacent features seen on these photos, from fault plane solutions of earthquakes, and from existing field reports. In central China the three major east-west trending fault systems are left lateral strike slip faults. Movement on these faults appears to displace much of China eastward, out of the way of the converging Indian and Eurasian subcontinents. Moreover, these large eastward displacements are a key to the understanding of the tectonics both of southern China, where normal faulting and right lateral strike slip faulting occur in Yunnan in contrast with thrust faulting in Szechwan, and of northeastern China, where extensional tectonics and basaltic volcanism dominate. Hence we relate all of the recent tectonics of China to the convergence of India and Eurasia during the Cenozoic at a rate of about 5 cm/year. The continental lithosphere of Asia appears to behave like a rigid plastic medium indented by India. In this context the large strike slip faults are analogous to slip lines in the indented plastic material.