In which year was the Tangshan earthquake?

The 1976 Tangshan earthquake was a Mw (Movement magnitude) .6 earthquake that hit the region around Tangshan, Hebei, People's Republic of China on 28 July 1976, at 3:42 in the morning. The maximum intensity of the earthquake was XI (Extreme) on the Mercalli scale. In minutes, 85 percent of the buildings in Tangshan collapsed or were rendered unusable, all services failed, and most of the highway and railway bridges collapsed or were seriously damaged.

The magnitude was initially estimated at around 8.1, subsequently recalculated to be 7.6 on the standard Mw scale. However, that scale measures only the total energy released by an earthquake, and earthquakes vary in how much of that energy is converted to seismic shaking.

The Tangshan quake, being relatively shallow, converted much of its energy to surface shaking, and on the Ms (surface magnitude) scale it also measured 7.6. (7.8 on the Chinese surface magnitude scale.) This "occurred on a near vertical right-lateral strike-slip fault, striking N40°E", causing the block on the southeast to side slide about three meters to the southwest. This resulted from tectonic compression on a nearly west–east axis. Surface rupturing occurred in five echelon segments extending eight kilometers through the center of Tangshan.

Tianjin, scholars accepted at least 300,000 died, at the time making it the deadliest earthquake in China and among the top disasters in China by death toll.