An earthquake measuring 6.1 on the Richter scale jolted East Kalimantan known as Borneo of Indonesia earlier Monday, the Meteorology and Geophysics Agency said in Jakarta.

The USGS also reported the quake at similar magnitude.

The quake epicenter, with the depth at 10 km, jolted 29 km northeast Tarakan of East Kalimantan, an official of the agency told Xinhua by phone.

But the USGS reported that the depth was at 9.02 km, according to its website.

The intensity of the quake was felt at 4 to 5 MMI (Modified Mercally Intensity) in Balikpapan town, the official said.

Indonesia is prone to quakes as it lies on a vulnerable quake-hit zone called "the Pacific Ring of Fire."