On September 12, the People's Committee of Quang Nam Province and scientists of the Vietnam Institute of Science and Technology announced their initial conclusions on the phenomenon of recurring earthquakes in Bac Tra My District.
However, these conclusions have failed to convince experts as they still believe that they do not identify the actual cause of the recurring earthquakes and their impact on the hydropower dam.
Dr. Le Huy Minh, deputy director of the Vietnam Institute of Science and Technology said that earthquakes in Bac Tra My District have become much more severe than they were in late 2011. However, these earthquakes were well below the magnitude capacity of the dam.
The experts, who are from the Institute of Global Physics and the Earthquake Information and Tsunami Warning Center, are now in Bac Tra My District, where the plant is located, to examine damages to the dam and find out realistic causes to the earthquakes.
They forecast that earthquakes may continue to occur in the near future but will likely not exceed 5.5 on the Richter scale.
However, Dr. Nguyen Hong Phuong, deputy director of the center said that more than 60 tremors have occurred in the area since 2011, but only 12 of them have been recorded due to lack of observation stations and equipment.
The country has 25 stations but they can only observe earthquakes measuring about 3.5 on the Richter scale.
There are now four accelerometers equipped for the plant by Electricity Vietnam Group (EVN) but only two of them are operational and only measure vibrations on the ground surface and fail to measure intensity of quakes, he added.
In the hydropower plant area, regional stations have recorded two quakes measuring 4.2 on the Richter scale in early September. Meanwhile, the stations missed smaller quakes while data recorded from them are necessary for experts to identify the scope and the cause of quakes.
There should be facilities installed right at the base of the hydropower plant to forecast and observe earthquakes, Phuong said.
It is worth mentioning that all scientists, including representatives of EVN have not affirmed with certainty that in future earthquakes may affect the Song Tranh 2 Hydropower Plant or not.
Meanwhile, both EVN and the Ministry of Industry and Trade have confirmed that the plant is safe after leakage repairs were completed in late August, but local residents are very worried about the series of tremors.
Locals are fearful for the safety of the plant, which is home to a reservoir that is among the largest in central Vietnam.
Dang Phong, chairman of the People’s Committee of Bac Tra My District said that people still worry that double earthquakes could break dams and they want scientists be sure about the consequences to the dam.
Tran Xuan Tho, member of the Standing Committee of the People’s Committee of Bac Tra My District urged scientists and EVN officials to give a definitive answer about the status of Song Tranh dam construction.
“With responsibility of 1.5 million people in Quang Nam, we firmly suggest that if Song Tranh dam is unsafe it should not accumulate water. We need a confidential report on how earthquakes affect dams so as to inform people to understand better,” said Mr. Tho categorically.
Le Phuoc Thanh, chairman of the People's Committee in Quang Nam Province, had earlier made a proposal to install earthquake monitoring systems to predict earthquakes, especially those near Song Tranh 2 Hydropower Plant.
We must place people's lives on priority, believes Thanh.