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本文利用经过拟稳和伪逆平差等方法处理过的大地测量资料,分析了鲜水河断裂带的现今构造形变。表明该断裂带在近东西向区域压应力作用下,呈压性反扭,为典型的蠕滑—粘滑型断裂带。 断裂带蠕动段以水平反扭为主,前兆显示“V字型”异常形态,震后呈对数衰减。在虾拉沱,水平蠕动年速率为7.17±0.03毫米,倾向蠕动年速率为1.04±0.03毫米,两者之比为7:1。在粘结阶段,断裂带闭锁段无明显活动;而快速错动阶段,震中区发生大量级的水平反扭错动(达米级)及其伴随的松驰下沉(达分米级)运动。 现今构造形变和历史大震表明:道孚以北为蠕动段,以南为闭锁段。据此,鲜水河断裂带来来如果发生大震,则危险区可能在南段。
In this paper, the present tectonic deformation of the Xianshuihe fault zone is analyzed using the geodetic data that has been processed by methods such as quasi-stationary and pseudo-inverse adjustment. It shows that the fault zone is compressive and anti-torsion under compressive stress in the near east-west region, and is a typical creep-slip-slip zone. The fractured zone was dominated by horizontal anti-twist, and the precursor showed “V-shaped” anomaly, which was logarithmically decayed after the earthquake. In Shrimp Tuo Tuo, the annual rate of horizontal peristalsis was 7.17 ± 0.03 mm and the annual rate of peristalsis was 1.04 ± 0.03 mm, the ratio of the two was 7: 1. During the bonding phase, there is no obvious activity in the locked section of the fault zone. In the rapid dislocation phase, a large number of horizontal anti-twisting (dyadic) and associated slack sinking (dyadic) motions occur in the epicenter . Today’s tectonic deformation and historical large earthquakes show that: the north of Daofu is a peristaltic segment, and the south is a closed segment. Accordingly, the Xianshuihe fault could cause a large earthquake in the event of a danger zone in the southern segment.