China News Service, Yibin, April 8 (Reporter Liu Zhongjun) The Sichuan Earthquake Administration officially released the earthquake intensity map of magnitude 5.1 in Xingwen County, Yibin, on the 8th. The intensity map shows that the highest intensity of this earthquake is degree VI (6 degrees). , the long axis of the isoseismal line is northwest, the long axis is 30 kilometers, the short axis is 14 kilometers, the VI degree (6 degree) area is about 379 square kilometers, involving a total of 7 townships in 2 counties of Yibin City, Xingwen County and Changning County.
At 7:50 on April 6, an earthquake of magnitude 5.1 occurred in Xianfeng Miao Township, Xingwen County, Yibin City (28.22 degrees north latitude, 105.03 degrees east longitude).
The Sichuan Earthquake Administration's field work team conducted an earthquake damage investigation in the disaster area in accordance with the "Earthquake Field Work Part 3: Investigation Specifications" (GB/T18208.3-2011) and "China Earthquake Intensity Scale" (GB/T17742-2020). Comprehensive application of instrumental intensity, aftershock distribution, focal mechanism, UAV remote sensing and other achievements, the intensity distribution of this earthquake was determined, and "Sichuan Xingwen 5.1" was compiled in accordance with "Seismic Intensity Map Mapping Specification" (GB/T38226-2019). Earthquake Intensity Map.
The Xingwen magnitude 5.1 earthquake intensity map shows that the VI degree (6 degree) area covers an area of about 379 square kilometers, mainly involving Xianfeng Miao Township, Shihai Town, Bowangshan Town, Jiusi Town, Daba Miao Township, Zhoujia Town, Meidong Town, Changning County, a total of 7 townships.
At 5:54 on April 7, an earthquake of magnitude 4.1 occurred in Daba Miao Township, Xingwen County, Yibin City (28.12 degrees north latitude, 105.15 degrees east longitude), causing a certain degree of superposition of earthquake damage.
Investigators from the Earthquake Administration conducted surveys in the earthquake area through aerial photography and other technical means.
Photo by Liu Zhongjun
Some houses in the Ⅵ degree (6 degree) area were severely damaged, a few brick-concrete structure houses were slightly damaged, a few brick-wood structure houses were moderately damaged, and most of them were basically intact; individual wall columns and wall-beam joints of frame-structured houses were cracked , the vast majority are basically intact.
Some towns and towns outside the VI degree (6 degree) area were also affected, and some old houses were damaged and damaged.
It is understood that the so-called earthquake intensity reflects the degree of damage to the ground, houses and other structures affected by the earthquake, including damage to buildings and changes in natural landscapes.
China's intensity is divided into 12 levels, the higher the level, the heavier the damage.
Among them, buildings with an intensity of six degrees and above will be damaged to varying degrees.
Generally speaking, in an earthquake, the closer to the epicenter, the greater the intensity value; the farther away from the epicenter, the smaller the intensity value.
"The earthquake intensity map reflects the scope and degree of impact on the ground caused by an earthquake," said Fan Kaihong, a senior engineer at the Earthquake Emergency Service Center of the Sichuan Earthquake Administration.
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