Geometric structure and formation mechanism of Lintong-Chang’an fault zone

• Published in: Acta seismologica sinica 2008-03, Vol.21 (2), p.156-169
• Main Authors: Shi, Ya-qin, Feng, Xi-jie, Dai, Wang-qiang, Li, Xiao-ni, Ren, Jun, Chong, Jin
• Format: Article
• Language: English
• Subjects: Depth indicators; Earth and Environmental Science; Earth Sciences; Earthquakes; Fault lines; Fault zones; Faults; Fractures; Geological faults; Geometry; Geophysics/Geodesy; Intervals; Outcrops; Plate tectonics; Seismic activity; Seismic engineering; Seismic phenomena; Seismic surveys; Seismology; Stress distribution; Strikes; Yttrium
• ISSN: 1000-9116; 1674-4519; 1993-1344; 1867-8777
• DOI: 10.1007/s11589-008-0007-9

The results from investigation of large quantity of fault outcrops and artificial earthquakes suggest that the Lintong-Chang’an fault zone mainly consists of two faults. One is the Majie-Nianwan fault that separates a branch of Wangjiabian-Houjiawan fault on the right bank of the Bahe River; the other is the Hujiagou-Shoupazhang fault that separates a branch of Zhongdicun-Tangjiazhai fault in Tongrenyuan and Shaolingyuan. As tensional dip-slip normal faults, the faults distribute with approximately parallel equal intervals in local regions and the profiles drop in a step-like form to the northwest, presenting a Y-shape combination. The result from deep seismic reflection indicates that the fault is about 5∼8 km in depth, which is not only a basement fault, but also a listric normal fault in the deep stratum. The Lintong-Chang’an fault is a typical outstretching rift system under the NS-trending tension stress field. At the same time, affected by the sinistral strike slip of the Yuxia-Tieluzi fault, the fault extends like a broom from the northeast to the southwest.