Where China's Tangshan earthquake had occurred it had been unknown and unnamed at the time. But It's now called the Tangshan Fault, in the Cang-dong fault system near that system’s intersection with the Yin Shan–Yan Shan mountain belt. The Tangshan Fault is a strike-slip fault oriented in a north-northeasterly direction. The main shock caused a 75-mile subsurface rupture that extended bilaterally north-northeast and south-southwest of Tangshan it also caused important surface faults to appeared.

This city of one million, about 68 miles experienced an earth quake that nearly decimated the city with a magnitude 7.8 along with an after shock 15 hours later. A huge amount of 240,000 people had been killed, and at least 500,000 more were injured this was the largest earthquake death toll in 400 years.

The earth quake occurred at 3:42 am on a convergent boundary with a fault system, Plates involved were Eurasian and North American tectonic plates.

Many strong aftershocks followed the main earthquake, two of which had magnitudes of 6.0 or more. A major aftershock of 6.1 magnitude struck 15 hours after the main earthquake. In the following days, there were many more aftershocks ranging in magnitude from 5 to 5.5. Several months later, on Nov 15, 1976, a magnitude 6.0 earthquake struck again the same region.

The Chinese government was ill-prepared for a disaster of this scale. The day following the quake, helicopters and planes began dropping food and medicine into the city. Some 100,000 soldiers of the People’s Liberation Army were ordered to Tangshan, and many had to march on foot from Jinzhou, a distance of more than 180 miles. About 30,000 medical personnel were called in, along with 30,000 construction workers. The Chinese government, boasting self-sufficiency, refused all offers of foreign relief aid. In the crucial first week after the crisis, many died from lack of medical care.

After a deadly dangerous earthquake Tangshan, China is now rebuilt with adequate earthquake precautions and home to millions of people and many tourists. There are still memorials and also given the nick name "Brave City Of China".

CITATIONS: http://www.nationalgeographic.com/features/04/forcesofnature/forces/e_6.html https://www.britannica.com/event/Tangshan-earthquake-of-1976 http://www.drgeorgepc.com/Earthquake1976ChinaTangshan.html http://www.history.com/this-day-in-history/worst-modern-earthquake