http://www.edwardgoldsmith.org/1020/dams-failures-and-earthquakes/
The Hoover Dam (originally called The Boulder Dam) is 142 metres high and the reservoir impounded by it contains a maximum of 35 Gm3 of water. Filling began in 1935.
The first shocks were felt in September, 1936. In the following year, as the water height of the lake reached 120 metres, 100 shocks were felt. In 1938, seismological stations set up in the area recorded several thousand shocks that would not otherwise be perceptible by man. On May 4th, 1939 – some 10 months after the reservoir had risen to a height of 145 metres, and when the water volume had reached its normal capacity of 35 Gm3 – a serious shock (with a magnitude of 5) occurred. Seismic activity further increased in the following years.
In all, 6,000 shocks were felt over an area of 8,000 square kilometres within a ten year period after the start of filling. In August and September 1972, two other serious shocks occurred in the area around Lake Mead. Both were of a magnitude of 4 and occurred during short periods when the volume of water stored in the lake was nearly 40 Gm3.
Significantly, there had been no reports of earthquakes in the area for 15 years prior to the filling of the lake – although the area is geologically complex (being composed of granite and gneiss, pre-Cambrian schists, Paleozoic formations, and Tertiary volcanic rocks) and several faults had in fact been identified bordering the lake.
Actually, it was originally called Boulder Dam in the building phase but was officially Named Hoover Dam when dedicated. The a-hole FDR changed it to Boulder because that’s the sort of thing a Democrat would do in order to deprive a Republican of any credit for doing something ahead of schedule and under budget. In 1947 it was renamed Hoover and has remained so ever since.
I have found this to be quite fascinating.
Using the moons gravitational pull and the tides to determine the highest potential of weight the water in oceans are exerting on fault lines to help predict earthquakes.