The co seismic and post seismic deformation velocities of M s 8.1 Kunlunshan earthquake on Nov. 14, 2001 were calculated from the results of 1991-2001 GPS data and 4 repeated GPS surveys after the event. The result in...The co seismic and post seismic deformation velocities of M s 8.1 Kunlunshan earthquake on Nov. 14, 2001 were calculated from the results of 1991-2001 GPS data and 4 repeated GPS surveys after the event. The result indicates the maximum co seismic and post seismic changes are 1.9 m and 0.08 m respectively. On the basis of the result of post seismic velocity, we used an elastic dislocation model to inverse the crustal deformation characteristics of eastern Kunlun active fault. The result shows that the domain motion of eastern Kunlun fault is left lateral and strike slip. The trend of eastward motion for the southern block of Kunlun fault implies redistribution and reaccumulation of energy after the earthquake. It is possible that the seismicity will migrate to eastern region in the future according to the trend that strong earthquakes along Kunlun fault extended from west to east during the last several decades.展开更多
In this work, the authors present some results of strain monitoring within the territory of Vietnam from 1984 to 2001. Data analysis shows that (1) the Phu Lien area is tectonically stable with low strain rate, 1×...In this work, the authors present some results of strain monitoring within the territory of Vietnam from 1984 to 2001. Data analysis shows that (1) the Phu Lien area is tectonically stable with low strain rate, 1×10\+\{-6\} /a; (2) the Hoa Binh area has indication of tectonic instability with relatively high strain rate of the earth crust: absolute value of the strain reaching 100×10\+\{-6\}, usual average strain amplitude of 60×10\+\{-6\}, whereas the monthly average strain intensity varies in a range from 30×10\+\{-6\} to 50×10\+\{-6\}; (3) there are clear indications of the strain state of the earth crust before occurrence of earthquakes of medium or higher magnitude. This is a very important indication in the research and short term prediction of earthquakes, especially for the areas with low seismic stability like the NW of Vietnam.展开更多
Global Positioning System (GPS) observations during four measurement campaigns from 1992 to 1999 are used in a study of the temporal and spatial variation characteristics of crustal deformation of active tectonic bloc...Global Positioning System (GPS) observations during four measurement campaigns from 1992 to 1999 are used in a study of the temporal and spatial variation characteristics of crustal deformation of active tectonic blocks in North China. The Euler vectors for these active blocks are determined on the basis of GPS velocities of a group relative stable points in 1992,1995,1996 and in 1996,1999 respectively. We have studied the relative motion between blocks at the boundaries and the intra block deformation field. We have also inverted the strain rate fields for these active blocks by bi cubic spline model based on the GPS velocity field. The results show that the intra block deformation rates are different from those in block boundary zones, and are also different in different periods; the deformational field is generally characterized by intra-block extension in North China.展开更多
文摘The co seismic and post seismic deformation velocities of M s 8.1 Kunlunshan earthquake on Nov. 14, 2001 were calculated from the results of 1991-2001 GPS data and 4 repeated GPS surveys after the event. The result indicates the maximum co seismic and post seismic changes are 1.9 m and 0.08 m respectively. On the basis of the result of post seismic velocity, we used an elastic dislocation model to inverse the crustal deformation characteristics of eastern Kunlun active fault. The result shows that the domain motion of eastern Kunlun fault is left lateral and strike slip. The trend of eastward motion for the southern block of Kunlun fault implies redistribution and reaccumulation of energy after the earthquake. It is possible that the seismicity will migrate to eastern region in the future according to the trend that strong earthquakes along Kunlun fault extended from west to east during the last several decades.
文摘In this work, the authors present some results of strain monitoring within the territory of Vietnam from 1984 to 2001. Data analysis shows that (1) the Phu Lien area is tectonically stable with low strain rate, 1×10\+\{-6\} /a; (2) the Hoa Binh area has indication of tectonic instability with relatively high strain rate of the earth crust: absolute value of the strain reaching 100×10\+\{-6\}, usual average strain amplitude of 60×10\+\{-6\}, whereas the monthly average strain intensity varies in a range from 30×10\+\{-6\} to 50×10\+\{-6\}; (3) there are clear indications of the strain state of the earth crust before occurrence of earthquakes of medium or higher magnitude. This is a very important indication in the research and short term prediction of earthquakes, especially for the areas with low seismic stability like the NW of Vietnam.
文摘Global Positioning System (GPS) observations during four measurement campaigns from 1992 to 1999 are used in a study of the temporal and spatial variation characteristics of crustal deformation of active tectonic blocks in North China. The Euler vectors for these active blocks are determined on the basis of GPS velocities of a group relative stable points in 1992,1995,1996 and in 1996,1999 respectively. We have studied the relative motion between blocks at the boundaries and the intra block deformation field. We have also inverted the strain rate fields for these active blocks by bi cubic spline model based on the GPS velocity field. The results show that the intra block deformation rates are different from those in block boundary zones, and are also different in different periods; the deformational field is generally characterized by intra-block extension in North China.
