The National Earthquake and Tsunami Warning Centre under the Instituteof Geophysics reported the first quake, measuring 4.3 on the Richterscale, occurred at 19:14 at a depth of 8.5km.
Two other earthquakes measuring 3.2 and 3.5 on the Richter scale struck at 20.23 and 21.42 respectively.
Residents in Hanoi also felt aftershocks of the quakes.
Nguyen Hong Phuong, Vice Director of the National Earthquake andTsunami Warning Centre, said Muong La is vulnerable to earthquakes as itsits on the Muong La-Bac Yen Fault. Other localities in theNorth-western region prone to earthquakes include Dien Bien city, LaiChau town, Muong Lay town, Tuan Giao town, and Tam Duong town.-VNA