Series of devastating earthquakes hit Yunnan region in China

More than 80 people have been killed and hundreds are injured during a series of moderate earthquakes that struck Chinese region of Yunnan this morning. The death toll may further climb as the quakes happened at a poverty-stricken mountainous region where telecommunications and traffic infrastructure were damaged seriously, making it difficult to collect information promptly, said a spokesman with the provincial civil affairs department. More than 700,000 people have been affected by this earthquake.

Earthcracks are seen on the road in a town in Yiliang county, Yunnan province Sept 7, 2012. (Credit: Zhang Guangyu / China Daily)

 

According to the China Earthquake Networks Center (CENC), a magnitude 5.7 earthquake hit the border area of Yiliang county of Yunnan and Weining county of Guizhou province at 03:19 UTC. The depth of its epicenter was about 14 km. It was followed by more than 60 tremors, with four above 4.0 on the Richter scale.

The first earthquake was recorded as M5.6 on September 07, 2012 at 03:19:42 UTC with epicenter 127 km (79 miles) NW (317°) from Liupanshui, Guizhou, China with depth of  9.9 km (6.2 miles)  and the second M5.6 occurred at 04:16:30 UTC and was located 2 km (1 miles) SW of Jiaokui, China at depth of 9.8 km (6.1 miles).

USGS Intensity Shake maps of two strongest earthquakes measuring 5.6

 

Usually events of this magnitude (5.6, 4.9, 5.6 and 4.8) would not be sufficiently large to be worth reporting. Surprisingly though they appear to have caused considerable damage. However, these very shallow earthquakes  had epicenters very close to the county town, which may have led to a high level of localised shaking that happened to overlap directly with an urban centre and high level of landslides contributed the significant death toll as well as economical damage.

USGS PAGER issued Orange alert level for economic losses.

 

Today’s earthquakes is the second deadliest in 2012. The quake-stricken area is relatively populous, which was one of the main reasons behind the heavy casualties, noted Huangfu Gang, director of Yunnan’s seismological bureau. The population density of the area is estimated at 205 people per square kilometer, nearly twice the figure for the whole province, which is 117 people per square kilometer.

Most of the damage has been caused by landslides and not by direct shaking. More landslides and rockfall is being triggered by the many aftershocks. More than 100,000 people have been evacuated and over 20,000 houses were damaged or had collapsed.

A boulder measuring 36 meter was blocking the river, creating a small lake.The current rainy weather is making the soil very unstable, thus triggering a lot of minor and major landslides.

Zhaotong, with a population of about 5.6 million, is prone to geological disasters. A magnitude-5.6 earthquake in 2003 killed four people and injured 594 in the county of Ludian. In 2010, rain-triggered landslides left 45 dead or missing in the county of Qiaojia.

A car is destroyed by falling rocks in Luozehe town and a collapsed house in Luozehe town of Yiliang county after the devastating September 7 earthquake /Credit: Xinhua)

 

Regional deadly earthquakes from 1500 to 2000
Date             Long.   Lat.     Mag.  Death                    Location
1536-03-20     102.1   28.1      7.2      7.2         WESTERN SICHUAN, CHINA
1551-00-00     105.2   25.8     5.0      many     GUIZHOU, CHINA
1733-08-02     103.1   26.2     7.5      many     YUNNAN, CHINA
1850-09-12      102.3  27.8     7.5      20650   EASTERN SICHUAN, CHINA
1896-02-14      104.9   29.2     5.8      26            EASTERN SICHUAN, CHINA
1917-07-31      104.0   28.0    6.8      1800       EASTERN SICHUAN, CHINA
1930-05-15      103.0   26.8    6.0      42             YUNNAN, CHINA
1935-12-18       103.6   28.7    6.0      100s        EASTERN SICHUAN, CHINA
1936-04-27      103.6   28.9    6.8      many       EASTERN SICHUAN, CHINA
1936-08-17      103.0   26.6    5.5      30             YUNNAN, CHINA
1952-09-30     102.2   28.3     6.8      236          WESTERN SICHUAN, CHINA
1966-02-05     103.1   26.1     6.5      200          YUNNAN, CHINA
1974-05-11      104.1   28.2    7.1      1423        EASTERN SICHUAN, CHINA
1995-10-23      102.2   26.0    6.4      81             SICHUAN-YUNNAN BORDER REG, CHINA

 

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