Abstract:Using GPS data of Crustal Movement Observation Network of China observed from 1999-2013 and data of Continental Tectonic Environment Monitoring Network of China from 2009-2013,combined with other published GPS velocity field were analyzed and a more complete horizontal velocity field covering the Tianshan mountain and its vicinity was obtained.Preliminary results Indicare that presentday strain rate field is consistent with the longterm tectonic settings in the Tianshan mountain and its vicinity.The deformation of Tianshan mountain is mainly characterized by nearly northsouth crustal shortening,and the principal compressive strain rate is about 45×10-9/a in the western part (~77°E),and about 10×10-9/a in the eastern part (~86°E).The northern Pamir thrusting fault zones and its northern TransAlay Range are in a compression,state,with a principal compressive strain rate of about(50-60)×10-9/a and with dilation rate of about(40-50)×10-9/a ,consistent with previous studies of 10-15mm/a crustal shortening rates observed from GPS velocity profiles in this region.In the eastern part of Pamir (~38°N),which is adjacent to the Tarim Basin,principal strain rate and dilation rate demonstrate that there is certain extension with a rate of about(10-20)×10-9/a .Direction of the extension is nearly westeast,which is consistent with the extensional strain state observed from previous geologic and seismic studies in this region.The other maximum shear strain rate,40×10-9/a ,appears in the northern Pamir thrusting fault zones,and another high value,30×10-9/a ,appears in the western Tianshan mountain (~78°E).
Wang Wei,Yang Shaomin,Tan Kai et al. PRESENT-DAY CRUSTAL DEFORMATION AND STRAIN RATE
FIELD OF TIANSHAN MOUNTAIN ANALYZED WITH GPS DATA[J]. jgg, 2014, 34(3): 75-80.