The Earthquake Information and Tsunami Warning Centre said the first earthquake, measuring magnitude 2.6, occurred at about 6.35 am in Ta Hoc Commune, Son La Province.
About 25 minutes later, a second earthquake measuring magnitude 4.2 hit the same area. Both had focal depths of about 12km.
The second tremor was strong enough for many residents to feel buildings and objects inside their homes shaking.
Rocks dislodged by the earthquake collapsed onto a house in Mai Son, Son La Province (Photo: Hong Tham).
Xiem, a local resident, said the first earthquake caused only slight shaking. The second, which struck shortly before 7 am, was stronger and lasted about 10 seconds.
“The second earthquake lasted about 10 seconds, making tables, chairs, the ceiling fan and lights inside the house shake violently,” she said.
The Vietnam Institute of Earth Sciences initially assigned both earthquakes a natural disaster risk level of zero.
The Earthquake Information and Tsunami Warning Centre and the Institute of Earth Sciences are continuing to monitor seismic activity in the area.
In 2020, the former Moc Chau District in Son La Province was hit by a magnitude 5.3 earthquake that caused significant damage to homes and infrastructure in several localities.
More recently, a magnitude 4.0 earthquake struck Muong Hung Commune in Son La in May 2026, causing noticeable shaking.