Updated : Sat, December 1, 2012,9:38 AM (GMT+0700)
The quake, which was located at 18.65 degrees north latitude and 104.81 degrees west longitude, occurred at 4:40:20 p.m. Hanoi time, said the Earthquake Information and Tsunami Warning Center under the Global Physic Institute.
The quake, with its epicenter being 10 km underground in the Lao territory, came from the Rao Nay fault that runs from northwest to southeast from Laos to Ha Tinh, the center said.
The intensity of quakes coming from the fault can reach 6 degrees, experts warned.
The quake, which broke out on November 15 near the Song Tranh 2 Hydropower Plant, has been the strongestin the province in the past 55 years.
On July 25, 1957 a 4.8-magnitude earthquake struck Bac Tra My, the Global Physic Institute said.