The 6 to 8 second- tremor caused shaking violently furniture, chairs, windows, fish tank, even cups and glasses on the tables inside houses and buildings.
Up to now, the Institute of Geophysics has no information about this aftershock.
Sharing with the reporters of the Sai Gon Giai Phong (SGGP) Newspaper, Deputy Director of Vietnam Earthquake Information and Tsunami Warning Center Mr. Nguyen Hong Phuong said that scientists had not yet ascertained the eye of the earthquake.
However, the powerful tremor might be due to operation of troughs of broken-lines underground in area of Cao Bang province, which is about 200 km far from Hanoi.
On November 21, capital city of Hanoi experienced a tremor, making residents worry about living condition.