Earthquakes rattled Greece’s volcanic island of Santorini every few minutes through the night and into Wednesday as authorities bolstered their emergency plans in case the temblors are a harbinger of a larger quake to come.

Greece is preparing for any scenario but experts are optimistic about the tremors that triggered an exodus of residents and visitors from the Aegean Sea island of Santorini.

Greek officials are warning those on the popular tourist island destination of Santorini to stay alert in the coming days due to increasing seismic activity which could mean a strong earthquake is possible.