These earthquakes mainly occurred in the provinces of Quang Nam, Quang Ngai, Son La, Dien Bien, Lai Chau, Bac Giang, Thua Thien Hue, Nghe An and the Gulf of Tonkin.
The Institute of Geophysics said those earthquakes reached 2.5 to 4.1 on the Richter scale. In 2015, the supervision and warning of earthquake and Tsunami were maintained 24 hours a day by the Institute of Geophysics.
