From the plaque on monument:

"During the Cold War, Mono County was home to one of many remote facilities used by the US Military to test new weapons and weapons systems.
A "secret military installation" operated by the US Navy was located along the south shoreline of Mono Lake.
During the 1950s and 1960s several branches of the US Armed Forces ultilized this test facility to conduct various research.
Numerous top secret exercises were actually performed here during what was called "Seismic Testing."
However with the expansion of other navy bases, growing public safety and environmental concerns this facility soon outgrew its usefulness.
In May 1962 all operations ceased and soon thereafter the facility was abandoned.
Although many scientists, technicians, soldiers and sailors worked at this installation for many years, all that remains today of their activities are a few remnants and the name "Navy Beach."


WHY THE NAME "NAVY BEACH"?
Several branches of the military used this site to conduct research during the 1950's & 60's. The Navy conducted tests on new weapons and weapon systems during part of this period.

In the mid-sixties, the Army Corp. of Engineers performed numerous top-secret exercises here during a seismic testing phase. The explosive charges used in the tests weighed five tons each and were cast at the Naval Ammunition Depot at Hawthorne, NV. The explosions were planned to simulate effects that nuclear weapons may have on waves, terrain, structures, equipment, etc. none of the tests actually involved nuclear weapons in any form. The explosions produced large, short duration displacements of the surrounding water similar to the displacements produced by undersea earthquakes. This, in turn, produced simulated "seismic sea waves". The tsunami-type waves produced by the underwater explosions at Mono Lake were small-scale versions, only about four feet high. Electronic wave gauges measured the growth of the waves as they approached the shoreline, and high-speed cameras photographed them as they surged onto special wave "run-up" ramps installed on the beach. The information gained from these tests also expanded our understanding of how tsunamis are produced in the ocean. More importantly, it has improved our ability to predict their occurrence and hopefully, to reduce loss of life from tidal waves. This facility was abandoned shortly after these tests were performed in 1966. All that remains today of these military activities is a remnant of a pier and the name "Navy Beach".