西藏玛尼7.5级震与云南的远场前兆异常

远场前兆，是一种场兆，它是地壳构造活动的反映，往往也是强震连发的异常表现，它显示区域构造应力场的增强作用。１９９６年２月３日丽江７．０级大震后，云南省的前兆异常突出。前兆异常分布广，异常种类也多；有新的趋势性异常出现，持续多年的继承性异常也很多，有些前兆异常幅度类似于孟连、武定、丽江三次强震前的异常图象。１９９７年７～９月，这些趋势性异常或继承性异常出现转折与恢复，一些短期异常也趋于结束。如果说云

The M7.5 Manyi Earthquake in Tibet and the Precursor Anomalies of Far Field in Yunnan

The far-field precursor, as a precursor, is reflection of tectonic activity in crust and also often is anomalous expression of earthquake occurrence in succession, which displays distinct effect of regional tectonic stress field. There were prominent precursor anomalies in Yunnan Province after the M7 3 large Lijiang earthquake on February 3, 1996, with broad distribution, diversity, new tendency and continuity for many years. Anomalous amplitudes of some precursors were similar to anomalous images before the three strong earthquakes, the Menglian, Wuding and Lijiang earthquakes. Turning and recovery of tendency or inheritance anomalies took place and some short-term anomalies tended towards end from July to September in 1997. It would have been very difficult for interpreting the anomalies if there had not been a strong earthquake in Yunnan region or a large earthquake in its surrounding regions to be about occur. On November 8, 1997, a large earthquake of M7 5 occurred in Manyi, Tibet, which just dropped in this earthquake occurrence period. It should be said that these precursor anomalies were related to the M7 5 large earthquake and belong to far-field precursor anomalies, thus which not only can interpret why no strong earthquake occurred though there were anomalies in Yunnan in 1997, but also shows the precursor anomalies were the far-field anomalies for large earthquake.