China 1976 or 1975 ... earthquake killed a quarter million.
Found this:
The China Earthquake of 1976
No other earthquake in this century has been as catastrophic or has claimed as many lives as the great earthquake that struck the city of Tangshan, in Northern China, on July 28, 1976.
Tangshan, a thriving industrial city with one million inhabitants, is located only about 95 miles east, and slightly south, of Beijing. Although the region had experienced moderate seismic activity in the past, the city of Tangshan has been built on unstable, alluvial soil. To make matters worse, The city is located in the center of an area with major crustal faults on four sides. Furthermore, a 25-mile long fault passes through Tangshan, where only few of its structures are earthquake-resistant.
In the early morning hours of July 28, while the city was asleep, the magnitude 8.0 earthquake with its epicenter right on the city broke a five-mile section of the fault. Along the west side of the fault the land moved five feet northward in relation to the land on the east side. The east block tipped downward at the northern end of the break, and upward toward the south end. Over a four-by-five mile area the devastation of the city was nearly total. The force of the quake motions were so strong that people reported being thrown in the air. Within seconds, thousands died. Property destruction was unbelievable. Bridges, railroads, homes, factories were completely leveled.
In the harbor city of Tientsin, 60 miles to the southwest, and in Beijing to the west, the quake jolts forced thousands of frightened people into the streets seeking refuge from aftershocks.
The extent of the destruction and number of deaths in Tangshan and elsewhere in China was never disclosed officially. However, based on the density of population, it was fairly accurately estimated that there were at least 655,000 people dead, and 780,000 injured. These figures make the 1976 Tangshan earthquake, the second worse earthquake in recorded history. The most destructive earthquake ever, as reported earlier, occurred at Hausien in China's Shensi Province in 1556.
This will top that.