A magnitude 3.2 earthquake struck Bao Lac Commune in Cao Bang Province at 3.19 pm on August 3, causing buildings to shake for several seconds after residents reported hearing a loud underground rumble.
According to the Earthquake Information and Tsunami Warning Centre under the Institute of Earth Sciences, the earthquake occurred at a depth of about 16.8 kilometres and was assigned a disaster risk level of zero.
The tremor was the third recorded in Cao Bang Province over the past five days. A magnitude 3.6 earthquake struck Bao Lac Commune at 9.44 am on July 30, followed by a magnitude 3.2 event in Hung Dao Commune at 8.51 pm on August 1, about 25 kilometres from the previous epicentre. Sunday's earthquake occurred roughly 23 kilometres from the August 1 epicentre.
Geological studies show that Bao Lac and Hung Dao communes lie along the Song Gam fault zone, one of the active fault systems in northeastern Vietnam. The area regularly experiences minor to moderate earthquakes caused by tectonic activity, although most cause little or no damage.
Vietnam is not located on the boundary of major tectonic plates but is crossed by several active fault zones, including the Song Gam, Song Hong, Son La and Lai Chau-Dien Bien systems. Most earthquakes recorded in the country are minor to moderate in magnitude and rarely result in significant damage.
