- Also called:
- Great Tangshan Earthquake
- Date:
- July 28, 1976
Tangshan earthquake of 1976
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What was the Tangshan earthquake of 1976?
The Tangshan earthquake struck on July 28, 1976, with a magnitude of 7.5, devastating the Chinese city of Tangshan, an industrial and coal-mining hub. Registering a magnitude of X (extreme) on the modified Mercalli scale, the quake's impact was felt as far as 680 miles (1,100 km) away.
Reported as one of history's deadliest natural disasters, the official death toll was approximately 242,000, though estimates suggest the actual number may have been as high as 655,000. In addition, at least 700,000 people sustained injuries. The destruction was widespread, with damage extending to Beijing. The majority of deaths occurred due to the collapse of unreinforced masonry homes while people were asleep. A major aftershock (magnitude 7.1) in Luanxian worsened the situation, causing more damage and hindering rescue efforts.
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Where did the earthquake occur?
The Tangshan earthquake occurred on July 28, 1976, with a magnitude of 7.5, and almost razed the Chinese city of Tangshan, an industrial and coal-mining center located approximately 68 miles (110 km) east of Beijing. The epicenter was in the southern part of Tangshan. Shaking was felt as far as 680 miles (1,100 km) away. The earthquake occurred along a previously unknown fault, the Tangshan Fault. The official death toll was reported as 242,000, but may have been as high as 655,000.
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When did the Tangshan earthquake happen?
The Tangshan earthquake occurred on July 28, 1976. The earthquake, which had a magnitude of 7.5, almost completely destroyed Tangshan, China. The official death toll was reported as 242,000, but it may have been as high as 655,000. Additionally, at least 700,000 people were injured. The earthquake was followed by strong aftershocks that continued for days.
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How strong was the earthquake, and how was it measured?
The 1976 Tangshan earthquake in China registered a magnitude of 7.5. The earthquake's magnitude was measured using a seismograph, and its intensity reached X (extreme) on the modified Mercalli scale.
The Richter scale is a quantitative measure of an earthquakeâs magnitude, which utilizes the logarithm of the amplitude of the largest seismic wave. The Mercalli scale measures the intensity of shaking in qualitative terms.
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What was the impact of the earthquake on Tangshan and its people?
The Tangshan earthquake on July 28, 1976, nearly razed Tangshan, China, resulting in extensive damage and casualties. Officially, the death toll was reported as 242,000, but it may have been as high as 655,000, with at least 700,000 more injured.
Most fatalities resulted from the collapse of unreinforced masonry homes where people were sleeping. The earthquake destroyed or severely damaged over 85% of buildings in Tangshan. Infrastructure and agriculture also suffered, with roads, rail lines, bridges, and other structures wrecked. Industries resumed operations within a few years, and new buildings were designed to be earthquake-resistant.
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Tangshan earthquake of 1976, earthquake on July 28, 1976, with a magnitude of 7.5, which nearly razed the Chinese coal-mining and industrial city of Tangshan, located about 68 miles (110 km) east of Beijing. The death toll, thought to be one of the largest natural disasters in recorded history, was officially reported as 242,000 persons, but it may have been as high as 655,000. At least 700,000 more people were injured, and property damage was extensive, reaching even to Beijing. Most of the fatalities resulted from the collapse of unreinforced masonry homes where people were sleeping.
The main shock struck at 3:42 am. Its epicentre was located in the southern part of the city of Tangshan, some 9 miles (15 km) above the earthquakeâs focus, and shaking was felt more than 680 miles (1,100 km) away in all directions. Later that same day, a major aftershock (magnitude 7.1) occurred in the city of Luanxian, some 43 miles (70 km) to the northeast. This aftershock caused additional damage and casualties and hampered efforts to rescue people already trapped beneath rubble.
The earthquake occurred along a previously unknown fault, now called the Tangshan Fault, in the Cangdong fault system near that systemâs intersection with the Yin ShanâYan Shan mountain belt. The Tangshan Fault is a strike-slip fault oriented in a north-northeasterly direction. The main shock caused a 75-mile (120-km) subsurface rupture that extended bilaterally north-northeast and south-southwest of Tangshan; it also caused prominent surface faults to appear in the city.
Approximately 3,650 square miles (9,500 square km) of the surrounding region endured earthquake intensities of VIII (severe) or above on the modified Mercalli scale. In the city of Tangshan the intensity reached X (extreme). The shaking, which lasted 14 to 16 seconds, transformed much of the regionâs exceptionally deep sandy soil into a fluidlike mass (liquefaction). Since few buildings were anchored to bedrock, the shaking and subsequent liquefaction of the soil destabilized and brought down most of the structures throughout the affected area. The quake either destroyed or severely damaged more than 85 percent of unreinforced houses, multistory buildings, and other structures in Tangshan.
The earthquake also took a toll on infrastructure and agriculture. Liquefaction, combined with the sudden emergence of surface faults, wrecked roads, rail lines, bridges, dams, wells, and other infrastructure. It also triggered sand blows throughout the region, which silted wells and irrigation ditches. Sand blows, which expel wet sand from the ground, result from the increased weight brought on by slumping layers of soil upon layers of waterlogged sand below. South of Tangshan, where liquefaction was the highest, the tremendous outpouring of sand caused significant damage to crops.