A state of emergency was declared on Santorini Thursday after a magnitude 5.2 earthquake shook the Greek island late Wednesday. The tremor is the latest — and strongest — in a series of quakes that have struck the island since last week,

Past tsunamis have hit Israel’s coast, and with Santorini’s seismic activity at an all-time high, the risk of another wave is being taken seriously. Authorities remain on high alert, as the region watches and waits to see what happens next.

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.