帕米尔邻近地区与川滇菱形块体邻近地区地震活动的相关性

STUDY ON RELATIVITY OF STRONGLY SEISMIC ACTIVITY IN THE PAMIER VICINITY AND SICHUAN-YUNNAN RHOMBUS BLOCK VICINITY

帕米尔邻近地区（简称西区）的强震活动频度明显高于川滇菱形块体邻近地区（简称东区）。西区发生的地震主要为中、深源地震，而东区发生的地震则全部为浅源地震；西区主要的地震能量在本世纪初释放，而东区在滞后了40余年后在本世纪中叶地震能量开始强释放。东、西两区的强震活动频次呈现准同步盛哀起伏，在50～60年代相继达到高潮，80年代以后两区均趋于相对平静；在时间序列上呈现东、西交替发生的特点，往往是西区先发生强震，然后在东区有相应的强震与之呼应。造成这些特征的原因是由于印度板块向北碰撞俯冲的不均匀性所致。印度板块的北西顶角向亚欧大陆板块插入较深，而北东顶角插入较浅，这种类似于跷跷板的模式，造成了西、东两头中深源地震和浅源地震相继交替发生。

The frequency of strong-earthquake activity in the Pamier Vicinity (Simply called as West Region) is obviously stronger than that in the sichuan-Yunnan rhombus block vicinity (simply called as East Region). In West Region are mainly intermediate and deep-focus earthquakes, while in East Region are all shallow focus ones. The seismic energy wasreleased in West Region principally at the beginning of this century, but East Region didn't start intensive energy releasing untill 40-odds years later, the 1950s. The frequencies of strongly seismic activities in both regions showed sub-synchronous rising and falling, and successively reached high tide in the 50s and 60s. As of the 80s, the seismicities in both regions all tend to be relatively calm,and show the feature that alternate occurrence of strong earthquakes between West Region and East Region in time sequence. Usually, strong earthquakes firstly occur in West Region, then to which there are earthquakes responding in East Region. These are caused by the inhomogeneity of the indian Plate's northern collision and subduction. The northwestern top angle of the indian Plate inserts Asia-Europe Continent more deeply, but its northestern top angle more shallowly. This pattern is similiar to aseesaw, leading to the alternate occurrence of the intermediate and deep-focus earthquakes in West Region and the shallow ones in East Region.