Watch HDToday. The movie "Earthquake Miracle" is based on real events in the Tangshan earthquake 43 years ago, telling a miraculous story of 10,000 people surviving. A 7.8-magnitude earthquake erupted in Tangshan on July 28, 1976. In just 23 seconds, Tangshan was razed to the ground. Miners were trapped underground, not knowing if they will see their families again.