A 6.5 magnitude earthquake shook Samoa late on Saturday evening; alarming residents and waking them back up near midnight.

The quake struck at 11.27 pm Samoan time and it lasted for over 30 seconds.

There was the first initial strike and then it was sustained for what some frightened residents said felt like eternity.

The Samoa Meteorology Office confirmed that the earthquake was 6.5 in magnitude at a depth of 10km, and did not generate a tsunami threat.

Volcano Discovery also immediately posted different measurements of the earthquake from different centres around the world.

The German Research Centre for Geosciences (G.F.Z.) reported that the quake measured 6.1 but cautioned that it could be revised as seismologists review data and refine their calculations.

Volcano Discovery also quoted a report by the United States Geological Survey (U.S.G.S.), which listed it as a magnitude 6.4 earthquake.

A third agency, the European-Mediterranean Seismological Centre (EMSC), reported the same quake at magnitude 6.2.

“Based on the preliminary seismic data, the quake should have been widely felt by almost everyone in the area of the epicenter.”