Central Vietnamese province hit by quake series, with cause unknown

A tremor measuring 3.4 on the Richter scale occurred at around 6:45 pm on Tuesday in A Luoi District, according to the Vietnam Earthquake Information and Tsunami Warning Center, which is managed by the Institute of Geophysics.

The quake is this month’s fifth tremor recorded in A Luoi and neighboring Huong Tra District, which struck on December 6,7,12 and 14 with a magnitude of around 2.5 to 2.9, the center said.

It is also the tenth temblor that has occurred in the area of Thu Thien-Hue this year, it added.

The province has experienced two quakes with a considerable magnitude, including a tremor in Phong Dien District in 1947, which measured 4.4 on the Richter scale, and a magnitude 4.7 earthquake in A Luoi in May last year, said Professor Nguyen Hong Phuong, deputy director of the center.

The epicenters of the five quakes recorded in December 2015 in A Luoi are marked on this map. Photo: Tuoi Tre

Two possible causes have been proposed based on the fact that the epicenters of the quakes are close to each other, the professor explained.

The first theory points to the natural reason that the temblors were triggered by the active tectonic plates as there are two fault zones within the crust beneath the Thua Thien-Hue surface, he said.

The second refers to the possibility that the quakes were initiated by the A Luoi hydropower reservoir, according to the expert.

The A Luoi reservoir was built on the A Sap River and put into operation in September 2011, with a total capacity of over 60 million cubic meters.

Local citizens have expressed their deep concern over the seismic activities and blamed the operation of the reservoir for the tremors, Nguyen Manh Hung, chairman of the A Luoi People’s Committee, toldTuoi Tre (Youth) newspaper.

Earthquakes brought about by dams or reservoirs are commonly harmless since their magnitudes are not significant, according to Prof. Phuong.

However, evacuation should be carried out in the area near the A Luoi reservoir and hydropower plant to ensure the safety of local people, he suggested.

To accurately identify the real cause of the earthquakes in A Luoi requires detailed and long-term study, the expert concluded.

Vietnamese Deputy Prime Minister Hoang Trung Hai has ordered the Ministry of Science and Technology to work with the Vietnam Academy of Science and Technology and relevant authorities to evaluate the situation.

Research institutes should continue monitoring seismic activities in the affected areas to provide prompt warnings, the deputy premier requested.