地壳垂直形变场与强震关系研究

Research on the Relationship between Vertical Crustal Deformation Field and Strong Earthquakes

根据不同时期的地壳垂直形变速度，研究了中国大陆地壳的垂直演变特征，结合1965—2005年中国大陆地区M≥7级的大震，研究了垂直形变演变与强震活跃时间段和相对平静时段的关系。并且依据1951—1990年中国大陆垂直形变速率图计算分析了垂直形变速率梯度，研究了高梯度带与大震的分布关系。中国大陆垂直形变速度的演变表明，在中国大陆出现NWW向的上升带和下降带相间分布，而且以上升为主，西部呈现“南升北降”等形变特点时，中国大陆的大震活动也相对活跃，当大面积下降变化为主，尤其是青藏高原表现为下降时，大震相对平静。M≥7级的地震绝大多数发生在水准网控制的高梯度带上，发生在不同高梯度带的交汇部位，转折部位、或者局部变化较突出的附近地带。

Based on the vertical crustal deformation velocities in different periods, the characteristics of vertical crustal evolution in Chinese mainland are studied. With the additional information from the Ms≥7 strong earthquakes occurred in China in the period of 1965 ～ 2005, the relations of the vertical deformation evolution with strong and relatively quiet periods of seismic activity are studied. According to the vertical deformation rate mapping for Chinese mainland during 1951 -1990, the relationship between high-gradient belts and strong earthquakes are obtained. The evolution of vertical deformation velocity in the Chinese mainland shows an alternative distribution of NWW uplifted zones and subsided zones, predominated by the uplift. When the deformation is characterized by uplift in the south and subsidence in the north, large earthquake will be relatively active. When large scale of subsidence takes place, especially when Qinghai-Tibet plateau subsides, there would be no great earthquake. Most of M≥7 earthquakes occur in the high-gradient zones controlled by the leveling network, in the intersection or turning parts of the different high-gradient zones, or in the place near the zone with obvious local variations.