Greece declares emergency after near-constant quakes shake up Santorini. Here's what we know

People wait to board a ferry to Piraeus, during an increased seismic activity on the island of Santorini, Greece. (Reuters)

After hundreds of undersea earthquakes shook Santorini, a resort island in Greece, the government declared a state of emergency late on February 6. The most powerful tremor — of 5.2 magnitude — struck a day earlier.

Greece is one of Europe's most earthquake-prone countries. The vast majority cause no injuries and little or no damage but the country has also seen deadly quakes.  Seismologists have said that the recent activity is unprecedented and could last weeks or months.

Santorini lies along the Hellenic Volcanic Arc, which stretches from the Peloponnese in southern Greece through the Cycladic islands. There are two volcanoes in the area — Nea Kameni, an islet within Santorini’s caldera and Kolumbo, a submarine volcano about 8 kilometers northeast of Santorini, which took its current shape following one of the largest volcanic eruptions in history, around 1600 BC.

Government spokesman Pavlos Marinakis confirmed that multiple emergency services have been mobilised to support the island.

“Fire departments, police, coast guard, armed forces, and emergency medical services have immediately reinforced Santorini and surrounding islands with additional personnel and specialized equipment,” Marinakis was quoted as saying by AP.

Here's what we know so far:

About 10,000 people have left on ferries and planes in recent days as hundreds of small quakes were registered in the surrounding sea, shaking buildings, kicking up dust on the island's rocky cliffs.

Authorities have banned access to several coastal areas and ordered schools on Santorini and the nearby islands of Ios, Amorgos and Anafi to shut for the week. Public events have been banned in Santorini and authorities were restricting access to clifftop areas that are among the island's biggest tourist draws.

Authorities halted construction and ordered residents and hotels to empty their pools to reduce the burden on the ground.

First responders, vessels and a helicopter were on alert in case of emergency.

Experts view the underwater location as a mitigating factor, noting that it significantly reduces the potential for widespread damage compared to land-based seismic events.

(With agency inputs)