Underground tremors recorded recently in Bac Tra My and Nam Tra My districts of central Quang Nam Province were caused by Tranh River hydro-power plant activities, according to geophysicists from the Ministry of Science and Technology.
The conclusion was made after the geophysicists finished a field research at 54 positions in the area, which started on Thursday.
Director of the Institute of Geological Sciences Tran Tuan Anh, head of the research delegation, said these kind of tremors, which were known as operational-induced earthquakes, were normal in areas where hydro-power plants were located.
Local residents could still live and work normally and the tremors would reduce gradually, he said.
Similar tremors were recorded near the Hoa Binh and Son La hydro-power plants and the phenomenon normally last around five years, he said.
Dr Le Tu Son from the Institute of Geophysics said the tremors recorded in Quang Nam did not exceed geophysicists’ forecasts and Tranh River hydro-power plant was built with a safety capacity against earthquake of up to 5.5 Richter scale.
However, geophysicists suggested local authorities work with the Viet Nam Institute of Science and Technology to install observation equipment in areas where tremors were recorded to give appropriate warnings.
The first tremors struck the areas in January of this year. At least three tremors have been recorded since November 16.
The most recent tremors occurred last Sunday night, causing aftershocks within a 30km radius.
