Prominent Greek seismologist Gerasimos Papadopoulos cautioned that the current earthquake sequence – displayed on live seismic maps as a growing cluster of dots between the islands of Santorini, Ios, Amorgos, and Anafi — could indicate a larger impending event.

The strongest earthquake recorded was magnitude 4.6 at 3:55 p.m. Sunday, at a depth of 14 kilometers (9 miles), the Athens Geodynamic Institute said.