HR: 0830h
AN: S41C-03    [Abstracts]
TI: The Features of Seismicity in North Area of Tibet Plateau and Interpretation of Rock Experiment
AU: * Chen, B
EM: chbbbc@sina.com
AF: The second monitoring center, 316 Xiying road, xian, Sha 710054 China
AB: There are many faults distributed in North area of Tibet plateau, The north border consists of Alkin, Qilian and Haiyuan faults. There are obvious characteristics of earthquake activities: 1).pseudo-periodic of quakes (Ms6); 2).alternative activity of combinative faults; 3).Occurring at the joint area of faults; 4).Speadup-turn rapture of deformation accumulation. Under the press-shear condition, we choose the above three faults to set up experiment sample. The load curve mirrors a pseudo-periodic feature of viseo-slip events. It shows that the time of accumulating the energy for a rapture event is similar under the stable movement of blocks. There is peak value of strain at the joint area of Qilian fault and Haiyuan fault. It is similar to the energy pattern reflected by fault deformation observation. This indicates that, under the constraint of the specific geometric structure and stress direction of the northern edge of the Tibet plateau, the joint area of the Qilian fault and Haiyuan fault is indeed an energy concentrating area. The distribution feature of the strain increment shows that, when it was close to the rupture, strain was in relative critical state. Rupture happens at the peak value area, and it causes a large stress drop that covers almost the whole area of the Haiyuan fault. At the same time, the joint region between Alkin fault and Qilian fault as well as the Qilian fault region that is close to Haiyuan fault form relative increasing region. This indicates that the rupture happens on one fault can influence other connected faults markedly, and increases the risk of ruptures on other faults.
DE: 1242 Seismic deformations (7205)
DE: 7230 Seismicity and seismotectonics
SC: Seismology [S]
MN: 2005 Joint Assembly