Joint exploration of crustal structure in Fuzhou basin and its vicinities by deep seismic reflection and high-resolution
The Fuzhou basin and its vicinities are located at the northern end of the southeastern coastal seismic zone of the mainland of China. By the joint explorations of high-resolution seismic refraction and wide-angle reflection/refraction as well as deep seismic reflection in the region, which is the first synthetic profile in China, its fine velocity structure and geometric structure from the ground to Moho discontinuity is obtained. The result shows that the crust is obviously layered with a thickness of about 32 km. Basically, it consists of two parts:upper crust and lower crust. The velocity of the upper crust is 5.9-6.2 km/s in which there is a 3-4-kmn-thick weak low-velocity layer between the depths of 10-15 kmn, while the velocity of the lower crust in the range of 6.3-7.2 km/s. There exists a strong velocity gradient layer about 3 km thick above the Moho discontinuity whose velocity increases from 6.5 to 7.27 km/s.There exist high-angle normal faults that are small in size and extend only in the shallow crust.These faults are the secondary developed on the hanging wall of westward dipping low-angle normal faults. Thus, their seismogenic ability is limited, however, there exists a high-angle deep fault in the crust from Changle-Zaoan fault zone to seashore fault zone. This deep fault has cut the interface between the upper and lower crusts and Moho discontinuity, and may be the deep structure to trigger destructive earthquake source in future to affect Fuzhou City.These results have advanced the detecting precision of the deep structure in the southeastern coastal seismic zone of the mainland of China. In the aspect of the combined.feature of the deep and shallow extensional structures that consist of the westward dipping low-angle normal faults and secondary normal faults on their hanging walls in the upper crust, it is firstly obtained that a united structural interpretation has deepened the knowledge about the deep dynamic process in the southeastern coastal seismic zone. At the same time, in synthetic application of deep seismic detecting methods for deep tectonic background, it possesses a wide referenced meaning to the other regions.
作 者： Zhu Jinfang Xu Xiwei Zhang Xiankang Huang Zonglin CHEN Xiangxiong Fang Shengming Liu Baojin Zheng Rongzhang 作者单位： Zhu Jinfang,Huang Zonglin,CHEN Xiangxiong(Seismological Bureau of Fujian Province, Fuzhou 350003, China)Xu Xiwei(Institute of Geology, China Earthquake Administration, Beijing 100029, China)
Zhang Xiankang,Fang Shengming,Liu Baojin(Research Center for Exploration Geophysics, China Earthquake Administration, Zhengzhou 450002, China)
Zheng Rongzhang(Institute of Geology, China Earthquake Administration, Beijing 100029, China;State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China)
刊 名： 中国科学D辑（英文版） SCI 英文刊名： SCIENCE IN CHINA (EARTH SCIENCES) 年，卷(期)： 2005 48(7) 分类号： P3 关键词： deep seismic reflection high-resolution seismic refraction wide-angle