Abstract:The Lajishan area is an earthquake tectonic window to reflect on tectonic activity and earthquake activity. The Lajishan fault has caused about 20 moderate earthquakes on the both sides of Lajishan mountain in documented history. Lajishan fault is still an active fault zone, and has structural conditions of medium-strong earthquakes in the region. The Lajishan area is at 3 500 m above sea level and is not convenient for study. It remains doubtful whether the Lajishan regional crustal deformation is still in the uplift state. This paper uses 1983-1995 leveling data, combined with 1999-2007 and 2009-2014 GPS data, to analyze the three dimensional crustal deformation of this area. Research shows that the west section of Lajishan fault has a vertical rate of 1±0.5 mm/a ,which proves that the area is still in the uplift state. GPS data also show horizontal compression in this area. The Lajishan area remains a crustal horizontal shortening deformation. The crustal shortening rate of the region has become smaller, and shows an obvious left-lateral strike-slip component after 2008. The results are corroborated by satellite imagery interpretation and field geological survey results. Under the control of extrusion environment, tectonic deformation in the area is still ongoing. This area is also influenced by the Riyueshan right-lateral strike-slip fault. We should be concerned and put attention to seismic risk at the western end of Lajishan fault.
ZHOU Lin,WANG Qingliang,LI Zhangjun et al. The Study of Crustal Deformation on Western End of Lajishan Fault Based on GPS and Leveling Data[J]. jgg, 2016, 36(12): 1056-1060.