A strong and shallow undersea earthquake shook part of Indonesia’s Aceh province Saturday, but there were no immediate reports of serious damage or casualties.

The US Geological Survey said the magnitude 5.9 earthquake was centered 362 kilometers (225 miles) east of Sinabang, a coastal town in Aceh province at a depth of 10 kilometers (6.2 miles).

Indonesia’s Meteorology, Climatology and Geophysical Agency said there was no danger of a tsunami but warned of possible aftershocks. The agency put a preliminary magnitude at 6.3. Variations in early measurements of quakes are common.