Introduction China is located in one of the most active seismic regions of the world and has been plagued by numerous destructive earthquakes during its long history. The most significant of these earthquakes, in terms of lives lost, was that which occurred in 1556. In the last twenty years China has experienced the second most destructive earthquake in its history. The following is a brief account of the 1556 and the recent 1975 and 1976 earthquakes.
The Great China Earthquake of 1556
The worse natural disaster in recorded history, at least in terms of lives lost, was caused by an earthquake in Hausien in the Shensi Province of China in 1556. The earthquake devastated 98 counties and eight provinces of Central China. The destruction spanned an area of 500 miles, and in some counties the average death toll was 60 percent of the population. A total of 830,000 people lost their lives, most of them from the collapse of poorly constructed houses. The magnitude of this earthquake has been estimated to be from 8.0 to 8.3 on the Richter scale.
The Haicheng Earthquake of February 4, 1975
On February 4, 1975, Haicheng, a town with about 100,000 inhabitants in the Liaoning Province of northeast China, was struck by a 7.3 magnitude earthquake. As early as 1970, the State Seismological Bureau, had identified the Liaoning Province as an area of high earthquake risk. Based on studies of precursor events and unusual animal behavior, a warning was issued by local authorities. Thus, when the earthquake struck on February 4, there were few lives lost as most inhabitants had evacuated to safer places. However property damage was high.
The China Earthquake of July 28, 1976 (The Tangshan Earthquake)
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.
Complete Destruction of the City of Tangshan by the July 28, 1976 Earthquake (Photo source: China Earthquake Administration)
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.
