The 1976 Tangshan earthquake () was a 7.6 earthquake that hit the region around Tangshan, Hebei, China, at 3:42 a.m. on 28 July 1976. 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 official report claimed 242,769 deaths and 164,851 serious injuries in Tangshan, but when taken into account the missing, the injured who later died and the deaths in nearby Beijing and Tianjin, scholars accepted at least 300,000 died, making it the deadliest earthquake in China and among the top disasters in China by death toll. The earthquakes The Tangshan earthquake was composed of two main shocks. The first struck at 3:42:56 in the morning (local time), approximately 12 km under the southern part of Tangshan. The was initially estimated at 8.1, subsequently recalculated to be 7.6 on the standard 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 (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", the block on the southeast side sliding about three meters to the southwest. This resulted from tectonic compression on a nearly west–east axis. Surface rupturing occurred in five en echelon segments extending eight kilometers through the center of Tangshan. The second main shock, with a magnitude 7.0 , or 7.4 , struck that afternoon at 18:45 near Luanxian, about 70 km to the east-northeast ("B" on the intensity map in the next section), just south of the northeastern end of the Tangshan fault. This occurred in a zone of north-northwest striking conjugate faults that cut across the north end of the Tangshan fault. The left-lateral motion here, along with the right-lateral motion on the Tangshan fault, suggests that as the crustal blocks to the west and east are compressed together the block between these two earthquakes is being squeezed out to the south. A long sequence of aftershocks followed, with twelve of magnitude 6 or greater. The first of these struck just three and a