云南思茅—普洱地区中强震群发生的构造机制

思茅－普洱地区震的发生，区域上受局部横向隆起构造的控制。隆起区发育晚更新世以来活动的两组断裂，北北西向断裂右旋，北东东向断裂左旋，局部兼有正断层分量。两组断裂彼此交切形成棋盘格式块体构造。在区域右旋剪切力作用下，块体发生绕垂直轴的顺时针旋转。块本旋转时，在其顶角端产生构造闭锁，形成应变积累，引发强震活动。多个块体旋转时，应变在多点集中，地震活动即出现群发型特征。

TECTONIC MECHANISM OF MODERATE STRONG SWARMS IN YUNNAN'S SIMAO PU'ER REGION

The occurrence of moderate strong swarms in Simao Puer is regionally controlled by transverse uplift structures.Two sets of faults have developed since Late Pleistocene.the one in NNW strikes right laterally,the one in NEE left laterally,and component of normal fault locally.The two faults inter cross each other,forming a block structure like a chessboard.Under the function of regional right lateral shearing force,the blockrotates clockwise along a vertical axis.When the block rotating,the tectonic blocks occur at the ends of apical angles,forming a strain accumulation,and triggering moderate strong earthquakes.When multiblocks rotatin,the strains are concentrated in multi points,so the seismicity appears group generating type.