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NO.1934-Qinghai earthquake in Yunnan, Qinghai
Author: Naiyimu
Map: Sun Lu/Proofreading: Gu Hanying / Edit: Yakult
In recent days, Geological movements in western China have been frequent, Yunnan Yangbi [yàng bì] and Qinghai Maduo successively experienced magnitude 6.4 and 7.4 earthquakes, and then more than 2,000 aftershocks occurred. The earthquake has touched the hearts of countless Chinese people.
Yangbi 6.4 magnitude earthquake epicenter, Mado 7.4 magnitude earthquake epicenter ▼
Yunnan and Qinghai are not adjacent, and Tibet and Sichuan are separated by the middle. However, the seismic areas of the two provinces are located in Hengduan Mountains , which is one of the most active geological areas in China.
Yangbi earthquake in Yunnan
According to the official measurement of China Earthquake Network, at 21:48 Beijing time on May 21, 2021, a magnitude 6.4 earthquake occurred in Yangbi County, Dali Prefecture, Yunnan Province (25.67º north latitude, 99.87º east longitude), with a depth of 8 kilometers.
near the epicenter of Yangbi County, Dali Prefecture,
very close to the county urban area
(Picture: google map) ▼
Yunnan Dali is well-known, " Cangshan snow , Erhai in April, Shangguanhua , Xiaguanfeng " is widely circulated. But in fact, what people usually call Dali only refers to "wind, flowers, snow and moon" and Dali Ancient City where Dali City is located, , and Dali Prefecture , which contains Dali City, is a larger scope, including multiple counties and cities.
Yunnan Province-Dali Prefecture- The location of Yangbi County ▼
is separated from Cangshan Mountain. Yangbi County, which faces Dali City, is one of them. Unlike Dali Autonomous Prefecture, which is mainly Bai, Yangbi County is an Yi Autonomous County. The ethnic subjects are different across a mountain. Such complex ethnic relations also indirectly reflect the complex geological structure of the place, the fault zones intersect each other, and earthquakes are prone to occur.
is separated by Diancang Mountain, and next door is Erhai Lake and Dali
(Picture: google map) ▼
The epicenter of the magnitude 6.4 earthquake of Yangbi is located near a local mountain plain called Dalanba in the county. Tea is abundant here, surrounded by dense tea mountains, which is one of the typical representatives of the Hengduan Mountains. The epicenter of this earthquake is only 9 kilometers away from Yangbi County. Although it is too close to the densely populated area and has a shallow depth of the focal magnitude, the magnitude is relatively low, and the destructive force generated is moderate, which still has a serious negative impact on the safety of life and property and production and life of the local people.
9 kilometers of people have to run for a long time, and earthquake wave will arrive at once...
(Picture: google map) ▼
Because the earthquake disaster occurred at night, There was a clear tremor in the twelve counties and cities in Dali Prefecture, and the earthquake source Yangbi County was the most severely affected. As of now, 3 people died and 32 people were injured in the earthquake. The
earthquake also seriously damaged the houses and production facilities of the affected people in Yangbi County. According to preliminary statistics, 192 collapsed houses are currently damaged, and 13,090 are generally damaged. In terms of water conservancy infrastructure, 1,073 water cellars were damaged, 45 people were damaged in drinking projects for 135 kilometers, and 11 reservoir dams were damaged; in terms of power communication, the flat slope 35 kV substation was damaged and the 10 kV high-voltage line was damaged, resulting in power outages of 602 households. These shocking data from show the huge destructive power of the earthquake to the local economy.The
earthquake had a more serious impact on road traffic. After the earthquake, the , the closest to the epicenter, , Hangrui Expressway, and 320 National Highway, parallel to it, were damaged to varying degrees. 6 other county and rural roads in were interrupted and 3 bridges were damaged.
Among them, the Shunbi section of Hangzhou Rui Expressway ( Dabao Expressway ) is interrupted by 2, and the Shunbi section of National Highway 320 is interrupted by 1. Once this large channel from Kunming, Yunnan Province to western Yunnan, , in western Yunnan, will mean that the traffic costs between the two prefectures of Baoshan , Dehong and Kunming in western Yunnan have increased greatly, and it is likely that it will need to detour the northern Lincang area.
320 National Highway, the key channel from Kunming to western Yunnan▼
At present, aftershocks in Yangbi area are still continuing . From May 18 to May 23, a total of 1,585 earthquakes of magnitude 0 or above occurred, including 40 magnitude 3 or above, 24 magnitude 3-3.9 magnitude 12 magnitude 4-4.9 magnitude 3, 3 magnitude 5-5.9 magnitude 6-6.9 1 magnitude 6.
The latest earthquake above magnitude 3 near Yangbi occurred on the morning of May 24
(Photo: China Earthquake Network Center) ▼
According to the expert analysis and research organized by the China Earthquake Network Center, the Yangbi magnitude 6.4 earthquake sequence is "foreshift-main earthquake-aftershock type". This is because before the 6.4-magnitude earthquake in Yangbi, Yunnan, there were a series of small earthquakes in the third and fourth magnitude earthquakes. This group of small earthquakes is closely related to 6.4-magnitude earthquakes, so the front earthquake called 6.4-magnitude earthquake . After the 6.4-magnitude earthquake, a series of earthquakes occurred, and these earthquakes were aftershocks.
Recently, earthquakes occurred near Yangbi
(Photo: China Earthquake Network Center) ▼
Aftershocks still occur, don't relax your vigilance.
Qinghai Maduo earthquake
According to the official measurement of China Earthquake Network, at 2:4 on May 22, 2021, Beijing time, a magnitude 7.4 earthquake occurred in Maduo County, Goluo Prefecture, Qinghai Province (34.59° north latitude, 98.34° east longitude) . The depth of the focal point of is 17 kilometers, and the average altitude within the range of 10 kilometers of the epicenter is about 4,200 meters.
Maduo County, Huanghe Township and this epicenter
(Picture: google map) ▼
"Southeast, northwest, Huangguoshu Ning", This is a rumor that people familiar with Qinghai often mention. It briefly summarizes which prefecture-level cities and autonomous prefectures are in Qinghai Province.
"Southeast, Northwest and North" is easy to understand. It is based on the location of Qinghai Lake as the benchmark. Haidong , Hainan, Haixi , and Haibei . "Ning" refers to the provincial capital Xining; "Huangguoshu" is a contiguous area with the lowest sense of existence in Qinghai Province, namely Huangnan, Guoluo and Yushu three autonomous prefectures, and their prefectures are all located in the eastern part of the province.
"Southeast, northwest, Huangguoshuning" ▼
The epicenter of the Mado 7.4-magnitude earthquake is located near a mountain called Mani Erigu in the county. is at a high altitude and is covered with ice and snow all year round. This place is located in the upper reaches of the Yellow River Basin, not far from Xingsuhai and Zha'e Lake. Requ, an important tributary of the upper reaches of the Yellow River, also flows through the foot of its mountain and flows into the Yellow River. Lek, a town named after the "Yellow River".
The epicenter of this earthquake is about 40 kilometers away from Maduo County. Although the magnitude of 7.4 is high, it is the strongest earthquake in my country since the 2008 Wenchuan earthquake. However, the population density in the earthquake area is relatively low and the depth of the focal quotient is relatively deep, so the destructive power generated by has been weakened.
The upper reaches of the Yellow River
The epicenter of this time is slightly far away from Maduo County
is particularly close to Huanghe Township, across the river ▼
The earthquake brought the local life and property safety and production and life. The negative impact of this earthquake on local people is limited. A total of 17 people were injured and no one died. 625 houses and 7 livestock sheds were damaged in Huanghe Township, Maduo County, the closest to the epicenter.
However, the earthquake caused traffic in the entire southeast Qinghai to become a mess. For example, the Yematan No. 2 Bridge in the Gongyu section of Xili Expressway collapsed, the Changmahe Bridge in the Huajiu section of Dema Expressway collapsed, and many road surfaces on 214 National Highway parallel to the Gongyu Expressway were destroyed.
Gongyu Expressway and Huajiu Expressway are the only two plateau Tibetan areas expressways in the southeastern Qinghai. The interruption of the two highways of and the destruction of National Highway 214 have caused the trunk transportation modes of Yushu, Maqin (local of Guoluo Prefecture) and other places to the provincial capital Xining and Republic of China (local of Hainan Prefecture), and the transportation costs have been temporarily interrupted. On the other hand, the destruction of Gongyu Expressway and National Highway 214 also briefly interrupted the road to Tibet from Xining through Yushu to Changdu, Tibet.
Dema Expressway Dejiu Section and Xili Expressway Xiyu Section ▼
According to the expert analysis and research organized by the China Earthquake Network Center, the Mado 7.4-magnitude earthquake sequence is "main earthquake-aftershock type". This is because there was no record of a foreshock in this area before the Qinghai magnitude 7.4 earthquake.
Recently, earthquakes occurred near Maqin
(Photo: China Earthquake Network Center) ▼
At present, aftershocks in this area are still continuing. As of 10:00 on the 23rd, a total of 1,169 aftershocks were recorded, of which the largest aftershock was magnitude 5.1, the aftershock activity level was about magnitude 6, and the spatial distribution length reached 170 kilometers. The impact range has included Dulan County, Haixi Prefecture, and Maqu County, Gannan Prefecture, Gansu and other places.
has a wide range of impacts
(Photo: China Earthquake Network Center) ▼
Is there any relationship between the earthquake in Yunnan, Qinghai?
Yangbi magnitude 6.4 earthquake and Mado 7.4 earthquake were more than 4 hours apart, with an epicenter of 1,000 kilometers apart, both located in the Hengduan Mountains. Is there any correlation between ?
Although it seems to be separated by the huge Sichuan Province and Tibet Autonomous Region
, one is at the northern end of the Hengduan Mountains , and the other is at the southern end▼
According to China Earthquake Researcher Sun Shiliu [hóng] of Taiwan Network Center, Qinghai Provincial Earthquake Bureau , Yunnan Provincial Earthquake Bureau and US Geological Exploration analysis and research showed that:
earthquake occurred in Yunnan and Qinghai. They have no direct relationship with each other, and there is no causal relationship between the earthquakes in .
Preliminary analysis by the US Geological Survey
(Figure: usgs) ▼
Yangbi 6.4 earthquake was caused by right-hand strike slip of the Weixi-Qiaohou-Weishan fault zone. This fault zone is under the control of the Hengduan Mountains and is a branch of the Zhongdian -Nanjian Fault Zone. It is also the result of the collision between the Simao plot and the Yangzi platform. It is also the Tengchong Volcano Area to the south. The geology of volcanic areas has a characteristic, and seismic group earthquakes often occur . These earthquakes all occurred on the Weixi-Johou- Weishan fault, which belongs to the same sequence of earthquakes that occurred in the same estuary area, thus forming seismic group seismic activity.
海水 6.4-magnitude earthquake surface wave propagation schematic
(Figure: usgs) ▼
Mado 7.4 earthquake was caused by left-hand strike slip in the Mado-Gander fault zone. This fault zone is located on the Kunlun fault zone, which is the result of continuous activity of the border fault of Bayan Kala block. Bayan Kala block is located in the north of the main area of the Qinghai-Tibet Plateau. It is one of the areas with the strongest crustal movement on the Qinghai-Tibet Plateau.
Mado 7.4-magnitude earthquake surface wave propagation schematically
(Figure: usgs) ▼
However, the root causes of these two earthquakes have similarities in terms of mechanism. both are subject to the squeeze effect of the Indian Ocean plate on the Asian and European plates, and both come from the same power source. Due to this extrusion, the stress in Yunnan and Qinghai has increased, which is equivalent to a stone with many stripes. When the stone is placed on the press, the stripes will accumulate stress. There is no relationship between these stripes, but the accumulation of stress between the stripes is related to being squeezed by the press.
are both near the active fault zone
(Picture: National Active Fault Display System) ▼
. The Indian Ocean plate is relatively active in recent times. Since early March this year, many major earthquakes of magnitude 7.0 or above occurred on the southeastern border of the Indian Ocean plate, that is, near the New Zealand region, and even triggered tsunami activities.
earthquakes are very frequent
(Picture: geonet) ▼
The energy release and strengthening of the Indian Ocean plate will inevitably affect western my country. Obviously, these two major earthquakes have a certain relationship with this.
Indian Ocean plate squeezes the Asia-European plate ▼
In the face of earthquakes that have occurred and aftershocks that may occur in the future, should prepare for the future and focus on it.
Qinghai earthquake zone needs to focus on secondary disasters that cause geology, landslides, landslides, etc. Earthquakes in western my country generally have some geological disasters above magnitude 6, such as earthquakes above magnitude 7 will increase significantly. Therefore, although there are not many people in the earthquake zone in Qinghai, it may cause geological disasters and will have a certain impact on roads and fields.
may also have a certain impact on rivers
(Picture: Yunzhi Hand/Tuzhun Creative) ▼
As for the earthquake zone in Yunnan, although the earthquake magnitude is relatively small, there may be fewer secondary geological disasters. , it is necessary to focus on whether the houses in the epicenter area are damaged. The degree of damage to needs to be identified by relevant departments. If the main structure of the house has been damaged, if there are subsequent aftershocks, it may collapse.
Yangbi Mountain area
(Picture: Call me loach / Tuchuang Creative) ▼
References:
.https://www.cea.gov.cn/cea/dzpd/index.html
2.http://www.ceic.ac.cn/speedsearch
3.http://www.neotectonics.cn/arcgis/apps/webappviewer/index.html?id=3c0d8234c1dc43eaa0bec3ea03bb00bc
4. Beijing News, Hongxing, China News Network, China Newsweek and other media interviewed Sun Shiliu, a researcher at the China Earthquake Network Center. Information Summary
5.https://www.usgs.gov/news/magnit ude-61-and-73-earthquakes-china
6.https://earthquake.usgs.gov/earthquakes/eventpage/us7000e54r/executive
7.https://earthquake.usgs.gov/earthquakes/eventpage/us7000e532/executive
8.https://earthquake.usgs.gov/earthquakes/eventpage/us7000e532/pager
9.https://earthquake.usgs.gov/earthquakes/eventpage/us7000e54r/pager
*The content of this article is provided by the author and does not represent the position of the Earth Knowledge Bureau.
cover: usgs
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