Causes of consecutive appearance of sinkholes in the ‘mineral valley’ of Nghe An

This afternoon (June 2), talking with VietNamNet, Mr. Ho Van Tu – Head of the Geological Union of the North Central region said that Chau Hong commune used to have many geological research works. The whole Quy Hop district is like a closed valley, surrounded by high mountains. The geological history of this region has a very complex structure.

According to previous research documents, Chau Hong commune is located on a deep fault structure zone named “Ngoc Hat – Long Quen”, extending nearly 100km from Quy Hop district up to Que Phong district (Nghe An). In this area, from 1981 – 1989, the Soviet Union cooperated with Vietnam to conduct geological exploration on the entire area in Chau Hong commune for tin ore and placer routes.

“When studying here, the entire quaternary sediment layer covered the limestone surface of Chau Hong commune. This limestone is characterized by many silk caves. This limestone area is crushed and broken, so there are more rows of silk sand than other areas”, Mr. Tu pointed out the geological features of this area.

According to Mr. Tu, this is an area where there are silt hoppers with underground water flowing from Chau Hong commune to Chau Quang commune (Quy Hop district) for about 20-25km.

“The cause of subsidence and the appearance of a “death hole” is due to the lowering of the groundwater level in the ground. When the sand-silk caves are connected, the water source will naturally drop. The mining of minerals using a lot of underground water is also affected, “- Mr. Tu informed.

The Geological Union also said that subsidence in Chau Hong commune has occurred from 2021 up to now. In particular, from March to May 2022, this situation occurs more often, with greater frequency and scale. This is the period with heavy rainfall, leading to a rapid rise in surface water level, which will open the sand silk caves faster.

“After the heavy rain, the sinkhole deepened. According to research by the North Central Coast Geological Federation, sinkholes are distributed individually, in many locations in Chau Hong commune. Subsidence has only cracked many houses and buildings, but no collapse has been recorded,” Tu said.

According to Mr. Tu, the subsidence also affects people’s lives in Chau Hong commune. Research results of the Geological Union show that sinkholes occur at and near geological exploration works that took place before.

According to Mr. Tu, Chairman of Nghe An Provincial People’s Committee Nguyen Duc Trung has concluded and requested to report the results before July 31 on the cause of subsidence in Chau Hong commune. The Geological Union will have a report on the cause of subsidence occurring continuously in the near future.

Earlier, in the morning (May 29), Chairman of Nghe An Provincial People’s Committee, Mr. Nguyen Duc Trung and leaders of departments and branches directly visited the situation of subsidence and cracking of soil, houses, constructions, wells. dry water in Chau Hong commune.

At the direct dialogue with the people of Chau Hong commune, talking about the causes of subsidence and cracking of houses, Mr. Nguyen Duc Trung shared, after 4 years, the people as well as the commune have continuously reported and reflected. shortage of clean water, cracking of constructions, subsidence of fields… but the treatment is still slow, the government will soon have an answer for the people.

As VietNamNet has reported, since 2019 in Chau Hong commune (Quy Hop district) there has been a situation of land subsidence and water wells.

Recently, this situation has taken place at an alarming rate when the whole commune had 299 wells with dry bottom, 191 houses cracked, dozens of “death pits”.

The continuous appearance of death pits in Chau Hong commune as well as the phenomenon of dry wells and cracks in houses made people extremely insecure and afraid.

Quoc Huy