It reached a sleeping industrial city at 3:42 in the morning with no warning at all. Eighty-five percent of Tangshan fell in seconds — the deadliest earthquake of the twentieth century.
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DownloadThe 1976 Tangshan earthquake struck on July 27, 1976, registering magnitude 7.5 (moment magnitude, Mw). Each whole step on the moment-magnitude scale is roughly 32 times more energy, so this released on the order of 178× the energy of a magnitude 6.0 earthquake.
Its epicenter was located near 39.57°N, 117.98°E, at a depth of about 23 km — a shallow crustal earthquake. Shallow earthquakes like this release their energy close to the surface, which is why the shaking near the epicenter was so violent.
An estimated 242,769 people were killed.