A 4-Richter quake shook Muong La district in the northwestern mountainous province of Son La in the early morning of August 20, becoming the sixth hitting the locality so far this year.

According to the National Earthquake and Tsunami Warning Centre under the Institute of Geophysics , the quake occurred at 6:50 and had its epicentre at 21.598 degrees north latitude and 103.969 degrees east longitude, with its depth of 10km.

Local authorities said no damage in property and lives have yet been reported. However, the quake left several cracks on the walls of some houses in It Ong town in Muong La district.

Earlier on August 11 and 12, two quakes scaling 3 and 3.1 Richter, respectively, also hit Muong La district – a vulnerable locality to earthquake as it sits on the Muong La-Bac Yen Fault.