施甸和永胜地震前后川滇流体异常变化

施甸和永胜二次地震前均有长达半年以上的流体趋势异常, 震前短期内还出现了显著的流体微观异常和宏观异常。 在震前短期阶段, 异常的数量及动态在时间上有起伏, 临震前出现“相对平静”状态; 异常在空间上有迁移演化现象, 表现为随着地震的临近, 异常由初期的分散状态转为向未来的震中迁移和集中。 以地下流体为主的宏观异常的出现, 可作为强震的短期信息, 但宏观异常与区域地震地质构造关系密切, 分布的位置距未来震中可能很远, 持续时间也可能较长。

The anomalous changes of underground fluid in the Yunnan and Sichuan Provinces around occurrence of the earthquakes of Shidian and Yongsheng

Before the two earthquakes, there are long-term trend ground fluid anomalies lasted for longer than half year. In the short term, there appeared some remarkable microscopic and macroscopic anomalies of underground fluid before two earthquakes. At the same time, the quantity and trends of the anomalies undulated, even appeared "relative calm" just before the events. The anomalies happened some migration and evolution in the space, displayed from the dispersion to the concentration toward the future epicenter. The appearance of the macroscopic anomalies, which are mainly composed of underground fluid, can be considered as a short-tern signal of a strong earthquake, but it is closely related to the regional seismotectonics, the distribution distance may be far and the lasting time may be rather long.