THE WATER LEVEL DYNAMIC TENDENCY OF WANQUAN WELL AND THE DATONG M6.1 EARTHQUAKE

In this paper, the anomalous variations in water level dynamic state of Wanquan well before and after the Datong M6. 1 earthquake has been discussed by combining regional structure and seismic activity, and it is considered that such a variation has reflected the strengthening and weakening process of the regional tectonic activity and the seismic activity is related with this process.
The Datong M6. 1 earthquake occurred on an anomalous background of water level rise of Wanquan well. Correponding with the anomalous background occurred several moderately strong earthquakes;by July of 1985, the seismic activity was migrated to the NEE Liulengshan fault zone, the water level rise for three years running began to show decline in August. After that, including the Datong M6. 1 earthquake, a series of moderately strong earthquakes occurred on Liulengshan fault zone,although the water level dynamic state sometimes showed a sudden rise, the dynamic tendency still showed decline. After the Datong M5. 8 earthquake on March 26, 1991, the decline speed was obviously decreased, the anomalous process gradually tended to end.