1927 Gulang earthquake

1On May 23rd, 927, an earthquake of magnitude 8 occurred in Gulang. The earthquake affected Gansu, Qinghai, Shaanxi and other places, and a flat land collapsed about 5 meters wide.

"Shengjing Times" recorded the cruel situation of Wuwei County and its surrounding areas being damaged by the earthquake: "The earthquake suddenly started, the valley cracked for a while, and the sun was dark. Six or seven out of ten people in the city collapsed, and the earthquake disaster has never been so cruel and serious.

Time of earthquake origin

1927 May 23, 6: 32: 47

Longitude and latitude

37.6 degrees north latitude and 0/02.6 degrees east longitude.

Epicenter position

Gulang County, Gansu Province, China

important

Grade?Eight

Epicenter intensity

1 1 degree

depth of the hypocenter

12km

Death toll

After the 4 147 1 Gulang earthquake, both ground deformation and building damage were extremely serious. According to the survey, the ground movement at that time had a strong direction, mainly in the north-south direction, followed by the east-west direction. It is very common that water and sand are sprayed by ground movement, wells and springs dry up or new springs proliferate.

The damage zone of Gulang earthquake is 600 kilometers long. According to the chronology of earthquake data in Gansu (Lanzhou Institute of Seismology 1979) and the investigation data, the areas seriously damaged by this earthquake are Gulang County and its northern areas of Shuangta, Sishui, Huangyang River and Zamu River. Buildings were severely damaged, caves all collapsed, and houses collapsed more than 90%. The southwest of the earthquake zone is mountainous, sparsely populated and the damage is unknown. Now, the severely damaged areas will be introduced.

ⅶ degree failure zone

Mainly distributed in Gulang County and its surrounding areas, Shuangta, Shuixiakou, Shenjiawopu, Dongqingding Line, Ancient City, Taergou, Zhangyibao and other areas.

(1) Gulang County and its vicinity. The Disaster Records of Gulang County records that an unprecedented earthquake was discovered in Gulang on April 23rd in the summer of Ding Mao in the 16th year of the Republic of China. At dawn, the first earthquake, its potential is still small, but the bed is full and the ruthenium button rings. People who are alert in their dreams think that the shock has passed and most of them have not avoided it. After a while, I came again. There was a thunderbolt, the valley was ringing, and the air was filled with dozens of feet of yellow dust. Suddenly, the heavens and the earth changed color, the sun and the moon were dull, the castles vanished in smoke, the mountains and rivers changed, the lanes were difficult to distinguish, and it was painful for miles. The county town, known as 300 households, killed or injured 7800 men and women, and all the houses in the city were destroyed. Ancient temples in and around the county, such as Zoroastrianism, Shimenshan Temple, Sansheng Palace, Notre Dame Palace, Sanguanlou, Shisan Temple, Arctic Palace, Laojunge, Xinlong Temple, Tuzhu Temple and Leizu Temple, were completely abandoned in the earthquake. Government buildings such as municipal government, yamen, judicial department and public security bureau. Are completely destroyed; Even well-built government offices and Catholic churches were mostly razed to the ground. Ground fissures, lumps and well water fluctuations in and around the county seat are also common. This shows that the damage in Gulang County is quite serious.

The destruction around Gulang County, according to the Records of Gulang County Disaster, Fiona Fang became a mound ruin within 50 miles, with numerous casualties. According to the survey, Gulang starts from Dongyue Temple in the east, reaches Dapotou in Heisongyi in the south, reaches Xiaogangou (Shahegou) in Xichuan in the west, and reaches Hujiabian in the north, about 50 miles away from the urban area. The ground fissures in Huangyangchuan, east of Gulang, are very developed, and the houses are seriously damaged. The wooden frame structure houses in Xiaogangou have all fallen down, the graves have been leveled, the treetops have been brushed over the ground, and the cracks in the flat land on the mountain have developed well; There are many cracks in the area around Heisongyi, mainly in the north-south direction. Almost all the houses collapsed, leaving only a Niangniang Temple and a mill, and the Great Wall collapsed in many places. All the houses collapsed, and the top of the mountain shook brittle, with many cracks and cracks. During the earthquake, cracks were closed one by one, and the ground was uneven after the earthquake. Even in hard places, cracks with a width of 0.5 meters appeared.

(2) the Twin Towers. The earthquake caused all the houses, temples and city walls to collapse. Only the wooden archway in the city did not fall down, and there were many cracks in the field. The flat ground sank into a ditch, about 5 meters wide and 200 meters long.

(3) Shuixiakou. Almost all the houses collapsed, and all the buildings and bungalows collapsed. The Great Buddha Temple collapsed, and the stone tablets in the temple twisted and fell to the northwest. At the beach and at the foot of the mountain, there are many earthquake cracks, and at the same time, large-scale landslides have taken place. The boulder fell from the mountain, causing bedrock cracks in the nearby granite, with the widest point reaching 0.5 meters.

(4) Shenjiawopu, Sitai and Holly Top. All the houses collapsed. Ground fissures and seismic scarps are extremely developed, forming a NW-trending seismic deformation zone, passing through valleys and ridges, and bedrock cracks and collapses.

(5) Ancient City, Targou, Zhangyibao and other areas. Almost all the houses and temples collapsed. Ground fissures are developed, rock collapses are serious, and Jing Quan fluctuates, especially in Zhangyibao Basin, where water spraying and sand blasting are common.

X degree failure zone

It is mainly distributed around Wuwei, Surabaya, Huangyang Town, Jinta and Nanying.

(1) Wuwei county and its vicinity. The fifth edition of Shengjing Times records that an earthquake suddenly occurred in Liangzhou (now Wuwei) on the morning of May 23rd this year. Once the valley cracked and the sun was dark. Six or seven of the ten urban houses collapsed. After detailed investigation, Wuwei County alone has a population of 35,495 (the original population is more than 80,000), 222,095 cattle, horses, sheep and livestock, and 0/0.93 million collapsed villages. The sturdy houses in Wuwei County and the churches of foreign missionaries were all knocked down by the earthquake. The manuscript of "New Chronicle" contains: The copper tower of Luosi Temple is more than five feet high ... In April of the Republic of China 16, the earthquake tower collapsed and broke into several pieces. During the earthquake, twenty-three brick buildings (twenty-four * * *) in Dacheng fell down, leaving only the north building and the mound fell down. The Luozang Brick Pagoda on the 0/3 floor of/kloc-is only one person high, and the Mosque and Daguang Temple Pagoda have fallen down. Temples were destroyed and damaged, and about three-tenths of houses were destroyed. The county government was razed, more than 10,000 houses in the county government were destroyed (sic, suspected 100-editor), and the county magistrate was killed. More than a thousand people were injured, and the cracks in the street were not wide.

The damage near Wuwei county is also very serious. The house in Zhoujiazhuang, north of the city, collapsed by 80%. The gate, three halls and back hall of Haicang Temple collapsed, and so did the towers. Only the main hall and stone tablet did not fall down, and there were cracks and water seepage. The tower of Dayun Temple in the northeast of the city, Qingyin Temple, Qingyin Tower, Nun Temple and Ma Temple all partially collapsed. Houses in the south of the city collapsed 10% to 15%, and cracks appeared in the riverbank outside the city. Although Guancheng Temple in the west of the city was not affected, the Guanyin Buddha in Guanyin Pavilion fell down, the eaves of Guanyin Pavilion fell off, the East Corridor of the Confucian Temple collapsed, and the archway collapsed. In a word, the vicinity of Wuwei county and its southeast and southwest areas are seriously damaged, and the areas south of the county and north of Daheyi-Baishuzhuang are slightly damaged, which are low-intensity abnormal areas, and the topographic deformation phenomenon near Wuwei is also very developed. According to records, the landslide in Nanshankou turned into a lake with wide cracks and water sandblasting.

(2) Huangyang Town. More than half of the houses in the city have collapsed, and those that have not collapsed are also inclined. Outside the city, the Temple of God of Wealth, the Niuwang Temple, the Sanguan Temple and the Huangyuting all collapsed, and so did the West Tower.

(3) Golden Pagoda. 70%-80% houses collapsed and the tower was 20 meters high. After the earthquake, only a mound was left and the archway collapsed. There are ground fissures and water spray splashing sand.

In addition, Surabaya, Sujiahu, Nanying, Hongshui River and other areas were also seriously damaged. Most houses and temples collapsed and there were many cracks on the ground.

ⅸ degree failure zone

Including Yongchang and Tumen. Yongchang County: According to the investigation, during the earthquake, the city wall collapsed, the crib mouth fell by about one third, and four city gates collapsed. Jade Emperor Temple was completely destroyed except the bell tower. More than half of the houses collapsed and many people were killed. Water inrush from ground fissures in the north of the city. In some places around Tumen, houses collapsed by about 40%-50%, many cracks appeared in the mountain, cliffs collapsed and springs dried up. 1927 Gulang M8 earthquake is another disastrous earthquake that occurred on the Haiyuan-Qilian Mountain fault zone after the 1920 Haiyuan earthquake. There are great differences in the previous research results about the rupture behavior of this earthquake. On the basis of multi-channel exposure and ground tracking investigation, combined with the analysis of relevant historical materials, this paper holds that this earthquake is the result of the joint action of Tianqiao Ditch-Huangyangchuan fault, Huangcheng Shuangta fault, Dongqingding fault and Wuwei Yitianzhu concealed fault, which constitute the Gulang nappe. The finite element numerical simulation results of the plane and profile deformation mechanism of Gulang nappe show that the stress and strain concentration areas are mainly distributed in the western section of Tianqiao Ditch-Huangyangchuan fault, Dongqingding area of Huangcheng-Shuangta fault and Gulangxia area where a hidden fault in Wuwei and Gulang-Shuangta fault are located, which is consistent with the distribution of the earthquake surface fracture zone, further indicating that the 1927 Gulang M8 earthquake is the result of the overall activity of the nappe.

seismic research

After the Gulang earthquake, professional investigation and research could not be organized at that time. The information of the earthquake site has only been reported and described in some newspapers, publications and local county records. Foreign missionaries in the earthquake-stricken areas and their neighboring areas also wrote some letters about their feelings about the Gulang earthquake. These data roughly describe the damage and earthquake situation of this earthquake. After the earthquake, Professor Yuan Fuli went to the Gulang earthquake area for condolences.

The systematic investigation of the great earthquake was carried out after liberation. From 65438 to 0954, the survey and design institute of the Ministry of Railways, the earthquake investigation team of Huangyang Reservoir of Gansu Provincial Department of Agriculture and Forestry, and the investigation team of Provincial Department of Industry visited the Gulang earthquake for Xiuhuangyanghe Reservoir, and compiled reports and photo collections. In the same year, Mr. Zhou Guang and Mr. Liu Bingjun of China Academy of Sciences also visited the Gulang earthquake area, focusing on the investigation and analysis of the earthquake deformation of Dongqingding-Shenjiawopu.

From 65438 to 0958, Guo Zengjian, Institute of Geophysics, Chinese Academy of Sciences, and others formed an earthquake prediction investigation team to conduct an on-site investigation of earthquake precursors at the Gulang earthquake site.

1972, 1974, 1975, the seismic geological team of the former Lanzhou Earthquake Brigade has done a lot of work on geological structure, seismic tectonic background and Dongqingding-Shenjiawopu seismic deformation zone in Tianzhu, Gulang and Wuwei areas successively, and has also done geophysical exploration in Wuwei and Gulang areas (mainly shallow electrical method)

1978- 1979, Teng Ruizeng, Lu Tianbao and Jia of Lanzhou Institute of Seismology conducted another investigation and study on the Gulang earthquake on the basis of previous work, focusing on collecting the data of seismic deformation zones. Through investigation and interview, the distribution, characteristics and mechanical properties of the main deformation zones of the earthquake are preliminarily determined, and the bedrock fracture, landform and Quaternary geology are investigated.

During the period of 1983, Chai Shuhua of Lanzhou Institute of Seismology and Kang Youli of Wuwei Seismological Bureau also conducted investigations and interviews on earthquake deformation.