A 6.2-magnitude earthquake struck off Indonesia 's coast, the northern part of Sumatra island, in the evening of April 6, according to the China Earthquake Networks Centre.

The quake’s epicenter had a depth of about 20 km and was initially spotted to be at 1.7 degrees north latitude and 97.1 degrees east longitude.

However, the US Geological Survey said the earthquake was measured 5.8 on the Richter.

Neither immediate report of damages nor tsunami warning was issued.

Earlier, on the early morning of April 4, a quake with magnitude of 7.1 rocked Java island.

As sitting on the Pacific "Ring of Fire", where the meeting of continental plates causes high seismic activities, Indonesia and Sumatra in particular, are frequently prone to earthquakes and volcanic eruption./.