Assuming that the contemporary tectonic activity in China can be treated as continuous, we have simulated 1245 present-day multiple-epoch GPS velocity solutions in the range of Chinese mainland, Mongolia, Myanma, Indi...Assuming that the contemporary tectonic activity in China can be treated as continuous, we have simulated 1245 present-day multiple-epoch GPS velocity solutions in the range of Chinese mainland, Mongolia, Myanma, India, Nepal and Himalayas with a bi-cubic spline interpolation function to inverse the integral horizontal velocity with the fitting accuracy less than 3 mm and obtained the strain rate fields in Chinese mainland. We have also analyzed the characteristics of spatial distribution of horizontal deformation and strain rate fields in Chinese mainland. The result shows that the analysis on the continuous deformation in the large-scale and dense GPS velocity fields can reveal not only the integral tectonic characters of Chinese mainland but also the tectonic characters in local regions. Generally, the magnitude and intensity of horizontal tectonic deformation have a mutation in the South-North Seismic Belt (95°E-102°E), which is stronger in the west than the east and stronger in the south than the north. Large strain rates are found in the areas as Kunlun block, Xianshuihe fault zone and central Yunnan, and the variation of velocity is very rapid. At the same time, the tectonic activity is relatively calm on Altyn Tagh fault zone, and extensive strain is found in the eastern part of central Tianshan.展开更多
Based on the multiple-term horizontal velocity solutions of 230 GPS monitoring sites in Tianshan and its adjacent region, the GPS site velocity fields and crustal horizontal strain fields in the area have been obtaine...Based on the multiple-term horizontal velocity solutions of 230 GPS monitoring sites in Tianshan and its adjacent region, the GPS site velocity fields and crustal horizontal strain fields in the area have been obtained. The results show that the crustal shortening rate of Tianshan, with the longitude （77°±1°）E as the boundary, gradually decreased towards two sides, from the south to the north, indicating that the pushing force of plate becomes weaker along with the fold deformation decreasing of the Tianshan. The direction of principal compressive strain of Tianshan and its adjacent area, nearly NNW, is basically perpendicular to the Tianshan cordillera trend, suggesting the distribution and variation of maximum principal compressive stress in Tianshan and its adjacent region resulted from collision and extrusion of Indian Plate. This paper indicates that the maximum shear strain field mainly con- centrates on two areas, one is Isyk lake of North Tianshan, Kyrgyzstan, and the other is the juncture of Jiashi （South Tianshan） and Pamir arc faults. In the above areas, it can be shown from the epicentral distribution that the strong earthquakes mostly occurs at the high shearing strain accumulation filed or its edge.展开更多
基金National Natural Science Foundation of China (40274007 and 40304002).
文摘Assuming that the contemporary tectonic activity in China can be treated as continuous, we have simulated 1245 present-day multiple-epoch GPS velocity solutions in the range of Chinese mainland, Mongolia, Myanma, India, Nepal and Himalayas with a bi-cubic spline interpolation function to inverse the integral horizontal velocity with the fitting accuracy less than 3 mm and obtained the strain rate fields in Chinese mainland. We have also analyzed the characteristics of spatial distribution of horizontal deformation and strain rate fields in Chinese mainland. The result shows that the analysis on the continuous deformation in the large-scale and dense GPS velocity fields can reveal not only the integral tectonic characters of Chinese mainland but also the tectonic characters in local regions. Generally, the magnitude and intensity of horizontal tectonic deformation have a mutation in the South-North Seismic Belt (95°E-102°E), which is stronger in the west than the east and stronger in the south than the north. Large strain rates are found in the areas as Kunlun block, Xianshuihe fault zone and central Yunnan, and the variation of velocity is very rapid. At the same time, the tectonic activity is relatively calm on Altyn Tagh fault zone, and extensive strain is found in the eastern part of central Tianshan.
基金National Natural Science Foundation of China (40074024) and Natural Science Foundation of Xinjiang Uygur Autonomous Region (200321101).
文摘Based on the multiple-term horizontal velocity solutions of 230 GPS monitoring sites in Tianshan and its adjacent region, the GPS site velocity fields and crustal horizontal strain fields in the area have been obtained. The results show that the crustal shortening rate of Tianshan, with the longitude （77°±1°）E as the boundary, gradually decreased towards two sides, from the south to the north, indicating that the pushing force of plate becomes weaker along with the fold deformation decreasing of the Tianshan. The direction of principal compressive strain of Tianshan and its adjacent area, nearly NNW, is basically perpendicular to the Tianshan cordillera trend, suggesting the distribution and variation of maximum principal compressive stress in Tianshan and its adjacent region resulted from collision and extrusion of Indian Plate. This paper indicates that the maximum shear strain field mainly con- centrates on two areas, one is Isyk lake of North Tianshan, Kyrgyzstan, and the other is the juncture of Jiashi （South Tianshan） and Pamir arc faults. In the above areas, it can be shown from the epicentral distribution that the strong earthquakes mostly occurs at the high shearing strain accumulation filed or its edge.
