Integrated Seismic Arrays for Imaging the North China Craton: the ¡°Destruction of the North China Craton¡± Project

It has been known, mostly according to the petrological and geochemical studies particularly the xenolith's data, that the North China craton (NCC), which is part of the Archaean Sino-Korean craton, had been reactivated since Mesozoic, and experienced widespread extension and volcanism through much of the Cenozoic. Currently the NCC is characterized by a thin lithosphere (as thin as 80 km according to published studies) and strong internal deformation, where over half of the eastern China's earthquakes occurred while the two major plate boundaries about China are thousands kilometers away. Although it is seismically quite active this region encompasses the China's capital and several mega cities which together hosts a large population and are very important to China's growing economy. Supported by the Chinese earth science community, the Chinese NSF recently started a major research program, the ¡°Destruction of the North China craton¡± (DNCC). About 150 million RMB (~ 20 million US dollars) will be allocated for this 5-year multi-disciplinary research program which is open for competition for all the earth scientists in China. Here we report one major seismic observation project of ¡°Integrated Seismic Arrays of DNCC¡± just funded during the first phase funding of DNCC. This observation-driven project integrates two groups at the Institute of Geology and Geophysics, Chinese Academy of Sciences and Peking University, and both institutions have their own broadband seismometers and have recently conducted pilot portable seismic array studies in North China. Up to seven linear broadband seismic arrays, each consists of 60-100 stations, are planned within the NCC. The principle objectives are to quantify the range and degree of the craton destruction in spatial domain with major focus on the east-west variation from the previously proposed intact craton in the west to the rejuvenated region in the east and the transition zone in the middle. With the expected imaging results of the crustal and upper mantle structures this integrated seismic arrays will provide the fundamental observational information to the overarching goal of understanding the ¡°Destruction of the North China cration¡±, which is one of the important tectonic processes in the evolution of the continents on the earth.