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The 1976 Tangshan Earthquake
The Tangshan earthquake is believed to be the largest and deadliest earthquake of the 20th century with its epicentre in Tangshan (an industrial city located in Hebei, People’s Republic of China about 150 km to the east of Beijing and is famous for its steel and coal mining industries) and a death toll of 255,000, while other reports claim it to be 650,000. The earthquake happened on the 28th of July 1976 during the early hours of the morning at 3:42 a.m. while the city was sleeping and the quake lasted for about 14 to 16 seconds. This earthquake recorded a magnitude of 7.8 on the Richter scale while some sources claim it to be 8.2 or 8.3. There was a huge aftershock after 15 to 16 hours of the main shock and it recorded 7.1 on the Richter scale.
- Tangshan earthquake of 1976
- Great Tangshan Earthquake
Abbreviations and explanation of terms used:
SSB – State Seismological Bureau
Sand blows or sand volcanoes - cone of sand formed by the ejection of sand onto a surface from a central point, with a crater at the summit and is often associated with earthquake liquefaction.
Liquefaction - the conversion of a solid or a gas into a liquid form
Cause of the 1976 Tangshan earthquake:
The cause of this earthquake was the rupture on the Tangshan fault that is a strike-slip fault oriented in the north – northeast direction and is 25 miles long. The rupture was due to the tectonic plates Amurian plate and Eurasian plate, sliding past each other.
The Yan Shan fold-fault zone lies to the north of Tangshan region. Towards the south of the Tangshan region, there are many other parallel fault zones one of which is Cangdong Fault zone. Tangshan is at the junction of Yan Shan fold fault zone and Cangdong fault zone.
This earthquake was a mid-continent earthquake. In mid-continent earthquakes the energy builds up slowly over a long period of time and the released energy is very high. The aftershocks from these earthquakes are spread over long span of time. These faults are dormant for a longer period of time and when they are active, they produce a series of earthquakes. The recent earthquakes in China are thought to be aftershocks of the Great Tangshan Earthquake of 1976.
Predictions and signs for the 1976 Tangshan earthquake:
- Wang Chengmin, a scientist who worked for the SSB Analysis and Prediction Department mentioned that an earthquake was to be expected between 22nd July 1976 and 5th August 1976 and alerts were mentioned for Beijing, Tianjin, Tangshan, Bohai and Zhangjiakou regions. Wang passed this information onto 60 people one of whom was an official Wang Chunging from Qinglong County.
- From the study of the tectonic conditions and other observations in June 1974, earthquakes of magnitude between 5 and 6 were forecast for the regions near Beijing-Tianjin-Tangshan regions and the Bohai-Zhangjiakou regions within the next 1 or 2 years.
- After the Haicheng earthquake in February 1975 many moderate earthquakes occurred in Northern China
- Based on observations in the various stations, new propositions were made in January 1976 by the SSB that, earthquakes may occur in the Beijing-Tianjin-Tangshan area and the Bohai-Zhangjiakou region in the year 1976 with magnitudes between 5 and 6. It was also predicted that the regions between 'Tangshan and Chaoyang' and 'Beijing and Tianjin' should be monitored and given special attention.
- Water in a well in a nearby village rose up and fell three times on the day before the earthquake and gas spouted out of a well in another nearby village, days before the earthquake, starting on the 12th of July 1976 and increasing on the 25th and 26th of July 1976.
- Some wells started to crack in nearby villages, people who grew fish at home found their fish restless, chicken were running around restlessly refusing to eat, mice and weasels were running around in fear
- There were roaring sounds and strange lights appeared, some people witnessed fireballs across the sky
- Level of groundwater rose and animals showed strange behaviours a few days before the earthquake
The Great Tangshan earthquake of 1976:
The Great Tangshan earthquake struck the city of Tangshan in North-Eastern China on the 28th of July 1976 at 3:42 a.m. when most people in the city were sleeping, giving them no time to leave the buildings. The quake lasted for 14 to 16 seconds with its epicenter in Tangshan although Tientsin was damaged very badly. Some people who were awake went under tables and heavy furniture to protect them from the falling debris.
There were no foreshocks that warned of an upcoming earthquake and hence the sudden strike hitting a magnitude of 7.8 on the Richter scale, left the city in rubble with thousands of buildings being destroyed.
- The earthquake happened along the Tangshan fault that was previously unknown and it falls on the Cangdong fault system near the intersection of the Yin Shan and Yan Shan Mountain Belt.
- The earthquake was given an intensity level of XI out of XII on the New Chinese Seismic Intensity scale. The earthquake destroyed the city of Tangshan and more than eighty five percent of the buildings were destroyed. The tremors from the quake were felt more than 1,100 km away in all directions. Damages were caused in the nearby cities of Qinhuangdao, Beijing and Tianjin, Beijing being 140 km away from the epicentre.
- Survivors saw the entire city flat to the ground and began digging into the debris to help trapped people. Injured people were pulled out and were laid on the roads. Medical attention was feeble as most medical staff were either killed or trapped under the debris and medical centres and the roads were destroyed.
- There was no water, food or electricity. Survivors set up groups and started emergency procedures, searched for food and set up temporary shelters as relief workers were stuck in traffic jams due to all roads being destroyed. Almost 80 percent of people trapped under the rubble were saved.
- Tremors were also felt in Beijing, where people were asked to live in the streets and open spaces
- An aftershock hit again on the same day afternoon in the city of Luanxian 70 km north-east of principal earthquake’s epicentre and recorded 7.1 on the Richter scale. Any remaining people under the debris were dead. Almost 242,419 people were dead and 164,581 were injured.
- The total loss was estimated to be 10 billion Yuan.
The Great Tangshan Earthquake
Death toll and Injury due to the 1976 Tangshan quake:
Since the earthquake occurred at a time of a series of political events, the correct figures for the death toll and damage were difficult to find.
- Reports from diplomatic observers estimate the death toll of the first shock to be 80,000 people.
- According to the Chinese government’s official report, the death toll was 242,000
- The Chinese Seismological Services reported a death toll of 242,419 in 1988.
- Other sources have reported the death toll to be 650,000 and 750,000
- The Hebei Revolutionary committee estimated the death toll to be 655,000 and injured to be 779,000
Reasons for increased damage and death:
- There were no foreshocks and so people did not sense any signs of an earthquake.
- The earthquake hit all of a sudden at 3:42 a.m., the time when most of the people were asleep.
- The focal depth of the quake was 15 kilometres (9 miles). A shallow depth of focus means greater damage as the focus is close to the surface of the earth.
- Very few buildings in Tangshan were built to withstand earthquakes as it was thought to be a region with lower risk for earthquakes.
- The city of Tangshan lies on unstable alluvial soil (a fine-grained fertile soil deposited by water flowing over flood plains or in river beds).
- The Chinese Government refused any International aid from the United Nations.
- People’s Liberation Army helped with relief work
- 56 medical teams were sent by Shanghai to Tangshan
- Initially temporary tents were set up to shelter people and later simple houses that can withstand tremors were built to provide shelter for people before the rain and winter set in.
- Rebuilding the city started immediately and the city was rebuilt completely with many steel and mining industries at present.
- Tangshan is called the “Brave city of China” and has more than 1.55 million population now
Damages due to the quake:
- Of the total buildings (85%) that were completely destroyed 93% were residential buildings and 78% were industrial buildings.
- Water pipes were damaged and 80% of water pumping stations were damaged, irrigation wells stopped functioning.
- 14% of sewage pipes were severely damaged, highway bridges collapsed, rails were bent and roads were fissured or covered with debris, railway stations, homes and factories were completely destroyed.
- Areas along which the fault line ran were sheared, mud and water were ejected out from under the ground.
- Power lines were damaged and people were thrown into the air due to the intensity of the quake.
- The principal earthquake caused a 120 km long subsurface rupture that extended bilaterally north-northeast and south-southwest of Tangshan region creating serious surface faults in the city
- The sandy soils were transformed into a fluid like mass due to liquefaction and this destabilised the soil bringing down most of the buildings
- Sand blows caused extensive damage to crops and farmlands, silted wells and irrigation ditches.
The Memory of Tangshan Earthquake-1976
Qinglong County, its preparations and lessons learned:
- Wang Qingchun who was one among the 60 people to receive news about an upcoming quake, took this information seriously and as a result, all communities of the Qinglong County held emergency meetings for instructing and preparing the villagers.
State council Document No.69 in Chinese and EnglishClick thumbnail to view full-size
- The secretary of the county Ran Guanggi requested officials to educate the 470,000 residents of the County about the expected earthquake and to move them to safer places. People were ordered to work and sleep outside the buildings which minimised the casualties in Qianlong.
- This was considered as public administration best practice, because public administrators of the Qinglong county used scientific knowledge and monitoring and prepared for the Great Tangshan earthquake. Not one person in this county died because of the earthquake although around 180,000 buildings were destroyed. There is news for one person having died of a heart attack.
- The Qinglong County issued a state council document in 1974 that alerted public officials about the possibility of an earthquake of magnitude 6 or above. This led to increasing efforts in preparing for disasters, detecting earthquake precursors, education about earthquakes and preparation for earthquakes. More than 70,000 books and 14,000 exhibition posters were distributed by the SSB to educate residents about the earthquakes.
Notes of the presentation at the conference on 16th July 1976
- In 1975, many community level, county level and village level observation stations were set up to monitor level, clarity, colour and temeperature of water, animal behaviour, geomagnetism and geo-electricity and an earthquake disaster management programme was headed by Wang Chunqing
- Between July 14th and July 21st of 1976 Wang Chunqing attended a conference conducted by the SSB and took notes of the presentation on 16th July 1976 by Scientist Wang Chengmin of the SSB's Analysis and Prediction Department.
- The people of the Qinglong county took this information seriously and started acting upon it.
- Classes in schools were conducted outdoors and students also played a major role in collecting data.
- An official warning was issued by the Chinese Community Party Committee of the Qinglong County on the 24th of July 1976 announcing of a devastating earthquake. Spring waters had become muddy according to a report from an earthquake monitoring station. The people were alerted through telephones and broadcasts.
- Temporary earthquake tents were set up by 26th of July 1976 and more than 60% of the Qinglong county residents moved into tents while others were warned to keep doors and windows open at all times. Businesses continued in outdoor locations.
- On the day of the quake, more than 180,000 buildings were destroyed in Qinglong County with 7,000 of them completely collapsed and only one person died of heart attack. Qinglong county sent a medical team and relief teams to the disaster area to help with rescue work and medical needs. This was a great lesson learned about preparing for the earthquake in China.
Commemorations were held in Tangshan on the 28th of July 2006 to mark 30 years since the 1976 earthquake devastated the city of Tangshan. Over 1,000 people attended the meeting.
Facts about the 1976 Tangshan earthquake:
- The earthquake had an aftershock that recorded 7.1 on the Richter scale and killed more people
- In 7,218 households, all members of the family were killed.
- Chinese seismologists had predicted that the region where Tangshan is located is likely to have major earthquakes.
- Corpses that were buried close to the residences were exposed to rain causing health issues and so they all had to be dug and reburied outside of the city.
- Scientists did not know that Tangshan was susceptible to large earthquakes before the 1976 earthquake hit
- Nearly 2,000 people are estimated to have died in the City’s biggest hospital because of the quake.
- It is believed that people who were working in coal mines would have been buried alive
- Majority of the buildings in Tangshan were not built to withstand earthquakes
- Water and food were scarce, some of which were parachuted and many people drank contaminated water out of pools
Eyewitness statements from survivorsClick thumbnail to view full-size
- Relief workers arrived late with food and water trucks due to road and rail damages and blockages.
- The death toll makes it the deadliest and strongest quake of the twentieth century after the 1964 Alaska quake that recorded a magnitude of 9.2 on the Richter scale.
- According to the reports from The Hong Kong Royal Observatory, although the magnitude of the earthquake was speculated to range from 6.3 to 8.3, the intensity was high.
- The meizoseismic zone (zone of maximum destruction) for this quake is elliptical in shape and covers an area of 47 km square.
- The 1976 Tangshan quake occurred during a series of quakes since the 1966 Xingtai earthquake, which are the 1967 Hejian earthquake with magnitude 6.3, the 1960 Bohai earthquake with magnitude 7.4, the 1975 Haicheng earthquake with magnitude 7.3 and the 1976 Horinger earthquake with magnitude 6.3.
- There were a series of quakes in 1976 that occurred from China to Greece which is believed to be due to the movement of the earth’s crust according to a Swedish expert Dr Marcus Baath.
- The entire city was rebuilt with the help of people from all over China and Tangshan is called the “Brave City of China.”
- There have been many unusual and seismic activities since 1972 in the fault regions around Tangshan like uplift of the Southern Piedmont area on the Yan Shan belt, surface deformations in 1973, Radon content in water, telluric currents, geomagnetism etc. These have been recorded in stations and observatories between Beijing and the Bohai coastal region and also in the Southern Liaoning Province.
- Research says that the recent earthquakes around that area are aftershocks of this huge earthquake
- The official death toll of this quake was released only in 1979
- There are controversies that the officials ignored the predictions of the scientists for an imminent earthquake.
- The Chinese leader, Premier Zhou Enlai died in January 1976. In July 1976 Communist leader Mao Tse-tung fell very ill and he died after 2 months. Since the earthquake happened during a period of agitation in the Chinese leadership (between the death of Zhou Enlai and Mao Tse-tung), it is seen by many in China as an omen for the death of Zhou Enlai and as the end of an era.
- Tangshan was closed to foreigners for almost 7 years after the disaster and only recently foreign journalists have been allowed into the city.
- Earthquake relief supplies from many countries and medical teams and relief materials from the UN were refused by the CCP leaders because they were promoting the Mao Zedong ideology (determination, sacrifice, and surmount all difficulties to achieve victory) and wanted to show its superiority. Also more importance was given to politics rather the relief work.
- The movie Aftershock was created based on the 1976 Tangshan Earthquake
Movie: After Shock 2010 Official IMAX Trailer
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The figures regarding damages, casualties and other information have been collected after research and data from various sources. Please feel free to comment if there are any errors so that this hub can be updated.
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