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Big earthquakes in history

By Philip Perez,2017-12-02 06:21:00
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Big earthquakes in history

Huaxian Earthquake 

January 23, 1556, the Shaanxi Huaxian earthquake of magnitude 8 occurred. Shaanxi Guanzhong area, fertile plains, densely populated, is one of the birthplaces of ancient Chinese culture.The earthquake, which occurred in Huaxian County, east of Guanzhong, killed a large number of people, a rare event in the history of earthquakes throughout history.According to historical records: "the death of the official history of military and civilian play a famous 830,000 odd, its unknown without the play of the number of people can not be counted."The intensity of the earthquake was 12 degrees, the area of the hardest hit areas reached 280,000 square kilometers, distributed in Shaanxi, Shanxi, Henan, Gansu and other provinces, seismic waves and more than half of China, the felt range as far as Fujian, Liangguang and other places. 

The earthquake caused such heavy casualties, the important factor is caused by the earthquake caused by a series of surface damage. Among them, the loess landslide and the loess collapse caused by the earthquake damage is particularly prominent, the landslide has blocked the Yellow River, causing Yan Sehu Lake lake lake water rose and the river water countercurrent.当Most of the local residents live in caves in the Loess Plateau and have suffered heavy casualties as a result of the collapse of the loess soil. Fractures, sand liquefaction and the destruction of the groundwater system have further exacerbated the disaster. The buildings in this area have poor earthquake resistance and the earthquake struck at midnight, leaving people unprepared and mostly crushed to death in their homes ;Severe secondary disasters such as floods, fires and diseases after the earthquake, coupled with the frequent drought in Shaanxi at that time, the people were hungry and did not have the ability to help themselves and recover. These were all causes that could not be ignored. 

Xingtai Earthquake   

At 0529 hours on 8 March 1966, a powerful earthquake of magnitude 6.8 occurred east of Longyao County, Xingtai Prefecture, Hebei Province, with a focal depth of 10 km and a epicenter intensity of 9 degrees. Following this earthquake, a 6.7-magnitude and 7.2 magnitude earthquakes occurred respectively southeast of Ningjin County on 22 March, and a 6.2-magnitude earthquake struck north of Lunan and a 6.2-magnitude earthquake east of Laolu on 26 March.During the 21-day period from March 8 to 29, there were five consecutive earthquakes of magnitude 6 and above in the Xingtai area, the largest of which was a magnitude 7.2 earthquake that struck southeast of Ningjin County at 16:19 on March 22. The quake was centered at 10 degrees at a depth of 9 kilometers and collectively referred to as the Xingtai earthquake.  

The Xingtai earthquake damage scope is very big, the instantaneous attack Hebei Province Xingtai, Shijiazhuang, Hengshui, Handan, Baoding, Cangzhou 6 areas,Eighty counties and cities, 1,639 townships and 17,633 villages have left the area with 8,064 dead, 38,451 injured and more than 5.08 million collapsed houses.The earthquake struck more than 110 factories and mines, hit 52 county and city post offices, damaged 16 piers and road cuts along five railway lines, including Beijing-Guangzhou and Shitai, damaged 77 road bridges and 2 local railway bridges, and destroyed 22 bridges for agricultural production, a total of 540 metres. 

The earthquake struck more than 110 factories and mines, hit 52 county and city post offices, damaged 16 piers and road cuts along five railway lines, including Beijing-Guangzhou and Shitai, damaged 77 road bridges and 2 local railway bridges, and destroyed 22 bridges for agricultural production, a total of 540 metres.The earthquake struck more than 110 factories and mines, hit 52 county and city post offices, damaged 16 piers and road cuts along five railway lines, including Beijing-Guangzhou and Shitai, damaged 77 road bridges and 2 local railway bridges, and destroyed 22 bridges for agricultural production, a total of 540 metres.Some ground up and down staggered tens of centimeters. Yan Jiazhai, Ji County, near the Shijin Canal dike was 2 meters above the ground, after the earthquake fell into the ground below 2 meters, 110 meters in length, 11 meters wide on the section, split there are 5 meters cracks, seam depth 4 meters.Both sides of the Fuyang River in the quake zone caused a serious collapse. The former road of Fuyang River in Rencun was compressed into a 48-meter-long, 3-meter-wide and 1-meter-high soil beam.   

When the 7.2-magnitude earthquake struck Xingtai, Shijiazhuang, Handan and Baoding on March 22, there were 361 landslides and 22 fires caused by landslide flystones, burning more than 3,000 mu of mountains.According to statistics from five regions of Xingtai, Hengshui, Shijiazhuang, Handan and Baoding, 422 fires broke out between mid-March and early April 1966, killing 39 people, burning 74 people and burning 470 earthquake shelters.

In the short time after the earthquake, earthquake rumors and earthquake misinformation events quickly spread, rumors alone involving Hebei, Henan, Beijing and other 3 provinces and cities, 8 regions, 40 counties and cities, affecting millions of people, causing panic among the affected areas and their neighbors, once mindless labor, decline in industrial production, reduced agricultural attendance, the indirect loss is huge. 

The Great Kanto Earthquake  

A magnitude 8.2 earthquake struck the Kanto region of Japan on September 1, 1923. The quake devastated the Kanto region, which included two major cities, Tokyo and Yokohama, 90 and 64 kilometers from the epicenter. Between 50 and 80 percent of the houses collapsed at the time of the quake.The earthquake caused fires in about 200 locations in Yokohama, and Tokyo was reduced to ashes by flames. A "fire stream" formed between high-rise buildings that was hard to see. There were 40,000 people in Tokyo who fled to an open space, where 33,000 people were burned alive because they had no way to go.The earthquake killed 143,000 people, 9 / 10 of whom were burned to death.The earthquake caused tsunamis, waves up to 9 metres high, sweeping public facilities and villages along the coast. The earthquake caused landslides that killed a considerable number of people when trains drove into the sea together. The earthquake produced outcrop faults with horizontal displacements of 4 to 5 metres, sinking 90 to 180 metres in some places in the centre of the bay and rising 229 metres in others. 

The most important enlightenment of the Kanto earthquake to the Japanese people and the whole world is the problem of comprehensive urban disaster prevention.Fire, flood, plague, water cut, power cut, traffic paralysis, lifeline engineering damage, man-made panic and social unrest occurred after the earthquake, these disasters because they are large areas, sudden, very difficult to rescue, so pre-earthquake to develop emergency plans, earthquake can effectively take emergency action, so as to achieve the purpose of disaster reduction.

Through this earthquake, Japan has provided valuable experience to the people of the world in the legal management of disaster prevention and comprehensive countermeasures, in urban planning, engineering earthquake resistance, road widening and network layout. Japan has moved from a major earthquake country to a major disaster prevention country.  

The Great Alaska Earthquake  

On March 27, 1964, at 5:36 p.m. local time, an 8.5 magnitude earthquake struck Alaska in the United States, with a depth of between 25 and 40 kilometers below the ground. The epicenter was about 150 kilometers from Anchorage, with an area of 130,000 square kilometers of damage and a felt area of 1.3 million square kilometers.  

The scale of surface deformation at the time of the earthquake was large, with a rock formation 640 km long split in two east of Anchorage and permanent deformation of the crust from as far away as Hawaii.There were many cracks in the coastal zone within a 320km radius of the epicenter. Waves from the earthquake reached the South Pole and changes in the water table caused by the earthquake affected Europe, Africa and the Philippines. 

Buildings were damaged during the quake, but the damage was caused not by tremors but by landslides, which formed four landslide faults during the earthquake in Anchorage, the epicenter of the quake.In general, building damage near landslide faults is unavoidable, but because Anchorage is a new city, most buildings are designed with seismic requirements in mind, so there are few collapses during earthquakes, despite varying degrees of damage, resulting in fewer casualties.

Haicheng Earthquake 

February 4, 1975 19:36, China's Liaoning Haicheng-Yingkou County occurred in the vicinity of a 7.3 strong earthquake, the epicenter of the intensity of IX degrees, the earthquake occurred in densely populated, industrially developed areas, is the largest earthquake ever recorded in the region.As China's earthquake department made the earthquake prediction, the local government in time before the earthquake to take strong anti-seismic measures, so that the earthquake disaster greatly reduced, greatly reducing casualties, but housing construction and other engineering structures have been damaged and lost to varying degrees,a total of 26,579 people were killed or injured in the earthquake, accounting for 0.32% of the total population, of whom 2,041 were killed or 0.02% of the total population. Most of the casualties were old, weak, sick, disabled, children and those who did not listen to the command.The earthquake caused the collapse and destruction of 5 million square meters of houses in cities and towns, 1.65 million square meters of damage to public facilities, 17.4 million square meters of damage to rural houses, 2937 damage to urban and rural transportation and water conservancy facilities, and serious losses of various equipment and materials, totaling about 810 million yuan. 

Tangshan Earthquake  

At 3:49:56 a.m. on 28 July 1976, a powerful 7.8 magnitude earthquake struck the city of Tangshan, the most tragic earthquake in the history of China and the world in more than 400 years.The earthquake damaged more than 30,000 square kilometers and affected 14 provinces, municipalities and autonomous regions of the country, equivalent to half the land area. The earthquake killed 242,400 people, seriously injured 160,000 and slightly injured 360,000. 

After the earthquake, Mount Tang was in ruins, with 5.3 million collapsed houses and 10 billion yuan in economic losses. Trains derailed, bridges collapsed, water supply and power supply, transportation, communications and other systems were damaged.

Tangshan earthquake relief work in the aftermath of the earthquake has made valuable experience, the international community fully affirmed the importance of the formation of the relief system to carry out earthquake relief.This work gradually improved in the subsequent work, it mainly includes: the implementation of state-level disaster response, the main force, professional team assistance, on-site rescue and support system in neighboring areas ;Hundreds of thousands of soldiers took part in the work of rescuing trapped persons, removing corpses and preventing pollution; 20,000 medical personnel, 280 medical teams and epidemic prevention teams,It played a key role in rescuing the wounded and preventing the epidemic; after the earthquake, construction teams and a large number of building materials were organized for more than 70,000 people in 14 provinces and cities throughout the country to quickly solve the problems of living and living. 

At the same time, the Tangshan earthquake also exposed the problems in our earthquake prevention and disaster reduction work: earthquake prediction, especially short-impending prediction is far from passing the mark; did not consider the threat of hidden faults to the city, so that there is no earthquake fortification; refused foreign aid so that China's rescue technology in a long-term backward state.  

San Francisco Earthquake  

April 18, 1906-A massive 8.3-magnitude earthquake and fire breaks out in San Francisco, USA, pictured, during the earthquake.  

  

The first large earthquake observed by modern seismic science in China  

Professor Fu Chengyi, a famous seismologist in China, once said: "The observation of earthquakes using modern scientific methods can be said to have started in China after the Great Gansu Earthquake of 1920."  

The Haiyuan 8.5 magnitude earthquake of December 16, 1920, was one of the strongest recorded in the history of earthquakes in China. Because the sea was under the jurisdiction of Gansu, many scholars called it the Great Gansu Earthquake. A plaque on the Santai Pavilion in Baitashan, Lanzhou, called the earthquake the "Great Global Earthquake". 

In order to study the causes of the earthquake and investigate the human and animal casualties and economic losses caused by the earthquake, in April 1921, the Ministry of Internal Affairs, the Ministry of Education, the Ministry of Agriculture and Commerce dispatched six members, including Weng Wenhao and Xie Jiarong, to the disaster area for investigation.The purpose of their investigation, as they say, is to pay attention to scientific research so that, in addition to investigating the conditions of the earthquake and the exploration of the collapse of the mountains and other phenomena, they are engaged in geological surveys to understand the origin of the earthquake and the relationship between the earth's crust.During a meeting with representatives of the Xingtai Scientific Symposium on Earthquakes in May 1966, Premier Zhou spoke highly of the on-site inspection by Weng Wen-hao, Xie Jia-rong and others. Premier Zhou pointed out: " Is it so bad to say that there was an earthquake in the old society that did not go into practice? The Great Liupanshan Earthquake of 1920 was always seen by some people.  

After the Haiyuan earthquake in 1920, the then Central Geological Survey began to take charge of earthquake work.Since the establishment of modern seismic stations in China and the occurrence of earthquakes anywhere in the country, the Central Geological Survey has tried to report them to the government and collect and collate them as research data.

Lu Shen Hai   

A major earthquake, may cause a large area of land uplift or subsidence, land subsidence if occurred in the lakeshore or coast, may cause flooding of the mainland, a large area of farmland, cottages will be submerged in a short period of time to form the earthquake secondary disasters. 

In 1605 (Ming Wanli 33) a major earthquake occurred in Hainan Island, lunar May 28 at midnight, the earthquake hit the northern Hainan Island of Qiongzhou, coastal land sank into the sea in large areas, land subsidence about 4.5 meters, dozens of villages submerged by the sea, people and livestock were killed.According to the genealogy of the Yizheng clan, "the earth shook, and there were seventy-two villages where people lived, and when they were trapped, those who went out were spared, miserable, and the mountains melted into the sea, so that they became fish, and the field nest belonged to Bochen."   

More than three hundred years after the Great Qiongzhou Earthquake in Hainan Province, we can still see the ruins of the village, the cemetery and the remains of various pottery pots, stone cauldrons and oil lamps.In front of all this awakening people, the earthquake disaster can not be ignored.

Slate Dancing 

Jiaodong Peninsula in 1939 occurred a 5.5 earthquake, the author visited the earthquake area in 1984, an old man who experienced the earthquake described the situation when said, "The earthquake occurred at dusk, I was squatting in the street smoking, suddenly thundered an earthquake came, the foot of a large stone in front of a thousand pounds, jumped more than a foot high."At first I hesitated not to believe the old man's recollection, and then I saw some materials, and quite a few such things, the earthquake of Assam, India, in 1897,"The rocks on the ground were thrown into the air like beans beating on a drum, large stones buried in the ground were thrown out, no cracks were visible in the surrounding soil, a stone pillar was pulled out of the ground without any soil on it, and a stone of granite weighed a ton and was thrown 8 feet into the air," the report said. In the 1923 earthquake in Kanto, Japan, potatoes grown in the fields near Mahontaka jumped out of the soil and strewed the fields, eliminating the need for farmers to plow potatoes.The 1971 California earthquake, when a 20-ton rescue train moved eight feet back and forth without leaving a trace on the ground, apparently emptied, mainly in the epicenter, a vertical movement seismologists believe is an important aspect of the quake's destructive power that should not be overlooked.In engineering seismic design, special attention should be paid to the vertical motion of surface structures such as dams and pipelines.

Boulder vacated

Accompanied by the earthquake, there was a strange phenomenon of boulders emptying, this can be the presence of all, there is no fiction.

The story takes place in Qinzhuang, Zaozhuang City.At about 1 p.m. on 20 June 1978, young women Li Jinhua, Sun Junfang and others were working in the fields, when they heard a rumbling sound coming from the foot of the mountain not far away. They looked in dismay and heard the same noise again. They saw a huge stone jump more than two feet high, the sound was still ringing, the ground was undulating like waves, and the people in the village were shocked and ran back in panic.Who can believe that this is true? Soon men, women and children came to the scene of the accident, saw the ground appeared more than 30 meters long a big crack, hard rock was staggered, jumped up that big stone placed there, people believe that it is true, the presence of an old man Li Chaoyang said: "I lived 72 years, has not seen such a strange thing." 

The site of the accident is Cambrian thin limestone, fracture development, the ground fissure is along the development of a group of fractures along the extension, near the east-west direction, but also along the direction of the valley, Earthquake workers considered the formation of the ground fissure to be the result of the regional stress field activities, because many places in Lunan at that time there were ground fissure, only in this particular location people personally saw the process.

Mexico City Earthquake   

Mexico has a popular folk song: "Guadalajara is built on a plain, Mexico City is built in the heart of a lake..."Mexico City was indeed the capital of the Aztecs, founded in 1325 on the island in the heart of Lake Tescoco, and later referred to as Mexico, meaning the middle of the Moon Lake. The poetic name of Mexico City seems to be the pride of the Aztecs, but the city built in the heart of the lake contains great dangers and disasters. 

At 0718 hours on 19 September 1985, a magnitude 8.1 earthquake struck near the Pacific coast of Mexico, followed 36 hours later by a powerful aftershock of magnitude 7.5.

Surprisingly, four coastal states in western Mexico closer to the epicentre suffered far less damage than Mexico City, 400 kilometers away from the epicentre, and the disaster seemed to depart from the general pattern of earthquake damage."A city built on a rocky foundation with a lot of earthquake damage, that's what disasters do," said George Prince, president of the Mexican Engineering Association. "We're going to have stronger, more destructive earthquakes. That's going to be terrible." 

Seismologists in Mexico used the strong ground motion records and pulsations from the earthquake to give quantitative results of the amplification of ground movements in the lake layers of Mexico City, which were 8 to 50 times larger than in the hilly areas, and 7.5 times larger than in the hard rock sites of the coastal epicentre.Seismologists in Mexico used the strong ground motion records and pulsations from the earthquake to give quantitative results of the amplification of ground movements in the lake layers of Mexico City, which were 8 to 50 times larger than in the hilly areas, and 7.5 times larger than in the hard rock sites of the coastal epicentre.   

Mexico City is a big city built on a foundation like "jelly in a bowl," said Professor Snr, a leading American geologist.

It is easy to see that Mexico City suffered from the long-distance effects of an earthquake just off the coast of Mexico in the Pacific Ocean, the main culprit being Mexico City's "jelly-like" lake bed foundations.

Earthquake in Turkey  

At 3 a.m. on 17 August 1999, a powerful earthquake of magnitude 7.8 struck the city of Izmit, west of Turkey, at a depth of 17 kilometres. The earthquake caused a massive rupture of the rupture zone of about 180 kilometres, with a maximum horizontal offset of 5 metres, a maximum vertical offset of 1.5 metres and a maximum width of 57 metres for the rupture zone.The quake affected an area of 150,000 square kilometers, about a fifth of the country. After the main quake, aftershocks were frequent and concentrated on the 200-kilometer-long NorthAnatolia fault zone. Large earthquake ruptures and strong vibrations caused the quake's most severe disaster, killing 16,000 people, injuring 26,000 others, toppling over 100,000 houses, leaving nearly 3 million homeless and causing more than $2 billion in direct economic losses.   

The lessons of the earthquake, which caused many casualties and huge economic losses, were profound. The fact that the earthquake occurred on a particularly active fault indicates that the fault was responsible for the earthquake damage. During the earthquake, the buildings (structures) on the fault zone were severely damaged. The buildings on the weak zone of the foundation were also severely damaged by severe vibration under the influence of the earthquake.Therefore, building site selection should avoid active faults and soft ground, and seismic safety evaluation and seismic design, increase supervision in construction, so as to improve the seismic performance of buildings.

Taiwan Nantou Earthquake

At 1:47 a.m. on September 21, 1999, a 7.6-magnitude earthquake struck the Jiji area of Nantou County, Taiwan, about 10 kilometers from its epicenter. The quake was triggered by a misalignment of active faults, which leveled most of the villages and towns near the fault. The entire disaster area lost 23,29 lives, injured 8,722 people, collapsed buildings, damaged 99,575 million buildings, and damaged 725 million people. 

 After the quake, which struck on a more active fault, buildings in and near the active fault were destroyed, homes were destroyed, bridges collapsed and water and electricity were cut off.It is only at the cost of blood and tears that one can truly appreciate the horrendous power of active faults moving mountains and fissures. Active faults are considered to be "time bombs" buried underground. We should pay close attention to the potential dangers of active faults. In particular, cities should strengthen the survey of active faults and formulate corresponding countermeasures.  

The seismic fortification of cities and the level of seismic fortification requirements have different effects at the epicenter of the earthquake. Buildings that meet the requirements for seismic fortification have either not been damaged, or have been significantly less damaged. The Taiwan earthquake once again reminds us that in urban planning and seismic fortification, we should strengthen the supervision of seismic design and construction.  

A huge earthquake that shook the sky and earth not only destroyed countless families and altered the topography of the fault line, but also prompted reflection. After the earthquake in Taiwan, the lack of advance planning, inadequate preparation and the severity of the disaster led to slow emergency response, chaotic field command and even more disastrous consequences. This is a painful lesson.

Earthquake in India 

On January 26, 2001, India's National Day, a powerful 7.4-magnitude earthquake rocked the subcontinent, including northwestern India, southern Pakistan, and Nepal. Gujarat, in northwestern India, was the worst-hit state, with 15,000 people confirmed dead by January 28.    

The Red Cross Society of China has provided $50,000 in financial assistance to the Red Cross Society of India, and the Chinese government has provided $5 million in emergency relief supplies to India.

Although the earthquake caused many casualties, but industrial facilities and oil facilities have not been too affected. 26 pm, basically returned to normal production. Gujarat's nuclear power plant without any problems. But the nearby waters have a large-scale crude oil pollution incidents, may be the oil storage tanks damaged by the earthquake caused oil leaks.

The earthquake received worldwide support. Britain, Switzerland and other countries sent rescue teams, with China, Britain, the United States, Canada, Germany and the European Union providing more than $11 million. Significantly, Pakistan is now putting aside its conflict with India over the sovereignty of Kashmir to provide relief to the disaster areas in India.