With the comprehensive analysis of the rock properties, the geological structures, the geography and the karstic hydrologic geology, the Chinese experts had separated the reservoir region of the Three Gorges into the following three parts before the construction of the Three Gorges Project. Their conclusion was then made as follows.
1. Sandouping-Miaohe Granite Reservoir Part
   There were no regional or zonal ruptures across the Sandouping-Miaohe Granite Reservoir Part. There was no historical record of felt quake there. The rock bodies in this part were generally waterproof without any geological conditions of the reservoir to cause a great earthquake. But it was still probable for the reservoir to cause a small shallow focus earthquake of about the third grade there.
2. Miaohe-Baidi-City Granite Reservoir Part
   There was the seismic geological background in the Miaohe-Baidi-City Granite Reservoir Part, which may cause an earthquake. The locations where there might be a strong earthquake of rupture were then the intersection between the Goddess-Mount Rupture Zone and the Jiuwenxi Rupture Zone which was actually 18 km away from the dam site of the Three Gorges Project, the intersection between the northern stretch of the Shijian Rupture Zone and the ruptures areas of the Zhigui Basin which was actually 52 km away from the dam site of the Three Gorges Project, and the parts of the Miaohe-Baidi-City Granite Reservoir Part where an earthquake of lava collapse may occur. It had been comprehensively concluded from the inspections and surveys of the experts that if an earthquake had occurred in the Miaohe-Baidi-City Granite Reservoir Part, the earthquake grade would have been that of about Grade 5.5 below Grade 6.
3. Reservoir Part More Than 500 m Upstream from the Baidi City
   The reservoir part more than 500 m upstream from the Baidi City was composed largely of Jurassic-System red sandstone and mudstone. The rupture structures there were extremely undeveloped. The hydrologic conductivity of this reservoir part was generally weak.
In accordance with the historical records and the supervisions by the time the Chinese experts had made their above conclusion, there had been rare earthquakes in the above three reservoir parts. Beside the geological conditions for earthquake occurrence in the reservoir part of the Wu River, there were rare geological conditions for earthquake occurrence because of the reservoir water storage. The reservoir part upstream from the Wu River to Baimachang was then an area where an earthquake of lava collapse may occur, but its earthquake grade would be that of about Grade 4 at maximum.

The Chinese experts had made the assumption of and then the solution to the extreme affection of earthquake caused by the reservoir water storage to the safety of the dam at the Sandouping Dam Site for the Three Gorges Project as follows.
If in one of the potential-earthquake parts, there had been an earthquake with its epicenter near the dam site of the Three Gorges Project because of the reservoir water storage, the dam would have been designed in accordance with the standard of Grade 7 above that of Grade 6 which was the maximum earthquake in the whole reservoir region calculated from the potential seismic intensities caused by the potential epicenter in accordance with the seismic decline principle. Such a design is actually used for the evaluation of the seismic intensity for the construction of a nuclear power station, which is actually far above the safe design of the dam of the Three Gorges Project. This was the final conclusion by the experts for the construction of the dam of the Three Gorges Project in consideration of the geological seismic conditions.

If an Grade-5 earthquake caused by the reservoir water storage for the Three Gorges Project occurred, a 10~20 km oval zone of the 7th-grade seismic intensity would form, which may affect the emigration and the environments. The civil structures would be damaged somewhat in accordance with the Chinese seismic intensity table. Some old houses would even collapse accordingly. But no big harm would be caused. Therefore, in the region of the 7th-grade seismic intensity, any production/ ore-mining enterprises had better not rebuild or newly build their structures on the unreliable slopes or on the land which might cause a landslide. Within the area of the 7th-grade seismic intensity, the soil/ rock bodies on collapse/ slide or unsteady soil/ rock bodies would sooner collapse or slide with an earthquake caused by the reservoir water storage of the Three Gorges Project, or would be obviously on the verge of collapse or slide or be unsteady. Such soil/ rock bodies still should be supervised after the reservoir water storage of the Three Gorges Project.

The China Three Gorges Project Corporation entrusted the seismic research institute under the State Seismic Bureau as early as in 1997 to develop and set up the earthquake supervision system to supervise any earthquake which may occur with the reservoir water storage of the Three Gorges Project. This institute:
1. Has adopted the digital remote-measuring technology to set up a seismic supervision network;
2. Has adopted the global positioning system and the precision lazar ranging system to set up a earth-crust variation supervision network;
3. Has set up the supervision center to supervise an earthquake caused by the reservoir water storage of the Three Gorges Project.
The seismic research institute had completed, had tested and had had the whole supervision system including the four supervision subsystems tested and accepted by the expert group by July of 2001. The seismic supervision system to supervise an earthquake caused by the reservoir water storage had been set up before the reservoir water storage of the Three Gorges Project. All this is rare in the history of the construction of the water resources and hydropower projects either all over China or all over the world.