The great Sonoran earthquake (M>7.2) ruptured the Pitaycachi fault on May 3,1887 and is the largest historic earthquake in the southern Basin and Range Province.
With the dawn of the atomic age seismic instruments became a premiere watch dog of world wide nuclear explosion testing.
This earthquake is significant for two reasons: First, just one year prior to this earthquake, Chinese scientists sucessfully predicted a major earthquake in this region. The evacuation saved many lives. Second, the Chinese scientists were not sucessful in predicting the Tangshan earthquake which resulted in between 250,000 and 500,000 deaths.
Although this earthquake occurred 200 km from Mexico City, the shaking of loose sediments in the capitol city was much stronger than at the epicenter. Nearly 10,000 people died and central Mexico City was heavily damaged. Liquifaction of the lake bed sediments was a critical factor.
1945 Trinity Nuclear Explosion, Alamogordo New Mexico
July 16, 1945
Early on the morning of July 16, 1945 the United States tested its first nuclear weapon, code named Trinity, in a remote area of the New Mexico desert, now known as White Sands Missile Range.
The detonation of such a large explosive device near Earth's surface sent compressional P-waves through Earth that were recorded by the early operating seismic stations, including TUC in Tucson, Arizona. The ability to record such events with seismometers began the branch of seismology known as Nuclear Explosion Monitoring.
The bulk of United States nuclear weapons testing occurred at Nevada Test Site located ~60 miles northwest of Las Vegas. The history of the United States Nuclear Weapons program is extensive and involves several government facilities around the country, over 1000 nuclear weapons tested, and some very gripping stories of atomic espionage.
