Possibility of reservoir induced seismicity round three Gorges Dam on Yangtze River

An 800-m-deep borehole was drilled for hydrofracturing in situ stress measurement near the dam based at Maoping town. Sixteen hydrofracturing in situ stress measurements were carried out at a depth of 155-790 m in the borehole. The average orientation of maximum horizontal principal stress is N69°W. It is shown that the linear relation of the stresses increase with depth. If water level increases 130 m after the reservoir impounding, based on in situ stress data from Maoping borehole and the frictional strength from the laboratory, the possible reservoir induced seismicity around the Yangtze Gorges dam is presented.