China News Service, Kunming, May 25 (Han Shuinan) At the fifth press conference of the Press Center of the “5.21” Yangbi 6.4 Earthquake Relief Headquarters in Dali Prefecture, Yunnan Province, held on the 25th, the Yunnan Seismological Bureau officially presented to the society Released the Map of Earthquake Intensity with Ms 6.4 in Yangbi, Yunnan.
Zhang Jianguo, researcher of the chief engineer of the Yunnan Earthquake Emergency Service Center and head of the disaster assessment team of the Earthquake System Field Command, said that the investigation and assessment of earthquake intensity is an important aspect of earthquake response and disposal work, which can provide an important reference for the deployment of earthquake relief work. Earthquake disaster economic loss assessment lays the core foundation and provides a scientific basis for the restoration and reconstruction plan of the disaster area.
The so-called earthquake intensity refers to the degree of damage to the ground, buildings and other structures, including damage to buildings and changes in natural landscapes.
The intensity of China is divided into 12 levels, the higher the level, the heavier the damage.
Among them, buildings with an intensity of 6 degrees and above will have varying degrees of damage.
Generally speaking, in an earthquake, the closer to the epicenter, the greater the intensity value; the further away from the epicenter, the smaller the intensity value.
The seismic intensity map reflects the range and degree of ground impact caused by an earthquake.
According to Zhang Jianguo, the Seismological Bureau of Yunnan Province conducted field surveys on 218 survey points in 53 towns and villages in 6 cities and counties in Dali Prefecture, and made reference to the scientific and technological support achievements such as fault structures in the earthquake area, distribution of aftershocks, focal mechanisms, and instrument intensity distribution maps. The strong motion observation records confirmed the intensity distribution of the earthquake.
After review and approval by the China Earthquake Administration, the Earthquake Administration of Yunnan Province officially released the "Map of Yunnan Yangbi Earthquake Intensity 6.4" to the public.
The picture shows the "Intensity Map of the M6.4 Earthquake in Yangbi, Yunnan".
Photo courtesy of Dali State Party Committee Propaganda Department
The highest intensity of the earthquake is Ⅷ degree (8 degree), and the area of Ⅵ degree (6 degree) and above is about 6,600 square kilometers (including Erhai Lake). The long axis of isoseismal is north-northwest trending, the long axis is 106 kilometers, and the short axis 76 kilometers, involving 6 counties and cities in Dali prefecture.
The area of Ⅷ (degree 8) is about 170 square kilometers, mainly involving 3 townships, Cangshanxi Town, Yangjiang Town, and Taiping Township in Yangbi County.
It starts from Hexi Village, Cangshanxi Town, Yangbi County in the east, Dalanba, Cangshanxi Town in the west, Shahe Village in Cangshanxi Town in the south, and Wanpo Village-Sangbulo Village in Yangjiang Town in the north.
Ⅶ(7 degrees) area is about 930 square kilometers, mainly involving Cangshanxi Town, Yangjiang Town, Fuheng Township, Taiping Township, Shunbi Town, Pingpo Town, Yunlong County Tuanjie Township, Eryuan County Xishan Township, Iron Smelting Township, Zijin Township of Weishan County, Taiyi Township of Dali City, a total of 11 townships.
From the Waihongyan Group of Taiyi Town, Dali City in the east, to the Menshen Group of Tuanjie Township, Yunlong County in the west, from Halashzuo Village, Shunbi Town, Yangbi County to the Enzuchang Group of Taiyi Town, Dali City, to Yangjiang Town, Yangbi County Baoheling.
The Ⅵ (6 degrees) district covers an area of about 5,500 square kilometers, mainly involving 42 townships in Yangbi County, Eryuan County, Yunlong County, Yongping County, Weishan County, and Dali City.
It starts from Jiangxi Village, Fengyi Town, Dali City in the east, to Dadianzi, Guanping Township, Yunlong County in the west, from the seat of Jijie Township Government in Yangbi County in the south, and reaches Huaping-Qiaohou Village in Qiaohou Township in the north.
In addition, some areas outside the VI degree (6 degree) area were also affected, and some old houses were damaged.
Zhang Jianguo explained at the press conference the intensity involved in the intensity map of the magnitude 6.4 earthquake in Yangbi, Yunnan.
Ⅷ degree (8 degrees): the displacement of individual column feet of timber frame houses, a few walls collapsed, some partially collapsed, most of the walls were cracked, the wall flashed outside, and the tiles were generally shattered; part of the wall of the brick-concrete house cracked; part of the wall column of the framed house , The joint part of the wall and beam is cracked, and a few shear cracks.
Degree VII (degree 7): The individual walls of the timber-framed houses collapsed, partially cracked, and the tiles were dropped; the joints of a few wall columns and wall beams in brick-concrete houses and frame houses cracked.
Degree Ⅵ (degree 6): A few walls of wooden frame houses cracked and shingles were dropped; individual wall columns and joints of wall beams in frame houses cracked.
According to previously released information, as of 11:00 on May 22, 14,122 houses in Yangbi County were damaged, of which 232 were collapsed. Most of the collapses were distributed within a radius of 5 kilometers from the epicenter of the earthquake. Residential dilapidated houses), 13930 rooms were moderately and slightly damaged (all houses in 9 villages and towns in the county were involved).