Credit: CC0 Public Domain

A strong, deep undersea earthquake shook eastern Indonesia on Friday, but no damage has been reported.

The 6.9 magnitude earthquake was centered more than 627 kilometers (389 miles) under the sea, according to the U.S. Geological Survey. Deeper quakes tend to cause less damage at the surface.

It was centered at 220 kilometers (136 miles) south-southeast of Katabu in Southeast Sulawesi province.

The Indonesian Meteorology, Climatology and Geophysics Agency released no .

Indonesia, a vast archipelago of 260 million people, is frequently struck by earthquakes, and tsunamis because of its location on the "Ring of Fire," an arc of volcanoes and fault lines in the Pacific Basin.