How unusual is Santorini’s seismic activity after swarm of earthquakes?

Hundreds of earthquakes have rattled the popular Greek island of Santorini over the past week forcing more than 10,000 people to evacuate. The quakes, measuring up to a magnitude of five, started on Friday and could go on for weeks, say experts. Although there have been no injuries or major damage so far, there is a high landslide risk on parts of the island. There are also fears the quakes could get stronger.

As a result, Greece has declared a state of emergency, evacuated residents and tourists, shut schools and advised people to avoid indoor gatherings and ports that are surrounded by sheer rock faces. Some of the measures have been extended to the islands of Amorgos, Ios and Anafi. On a brief visit to the island on Friday, Prime Minister Kyriakos Mitsotakis urged the public to remain calm and follow the advice of the civil protection service.

He added: ‘I want to assure the residents of Santorini and the neighbouring islands, which are being tested these days, that the state mechanism is on their side. ‘We hope this phenomenon ends quickly and the island fully returns to its normal pace.’. Greece sits on multiple fault lines and is one of Europe’s most earthquake prone countries. Quakes across the country happen every two to three days on average, though they are pretty mild compared to some of the more powerful ones felt in other parts of the world and generally cause few injuries and deaths and little damage.

What sets these earthquakes apart from previous tremors is their extremely high frequency. Earthquakes are not uncommon on Santorini and in 1956 was actually struck by one of the most serious quakes to affect Greece over the past 100 years. A 7.7-magnitude temblor, dubbed the Amorgos earthquake, triggered a roughly 20-meter (65-foot) tsunami, causing significant damage in Amorgos and Santorini and killing more than 50 people.

Santorini is also the site of one of the largest volcanic eruptions in human history – although this was a very long time ago, in 1,600 B.C. Known as the Minoan eruption, it destroyed much of the formerly round island and is thought to have contributed to the decline of the ancient Minoan civilization. Santorini is situated along the South Aegean Volcanic Arc, a string of volcanoes from the Peloponnese in southern Greece through the Cyclades Islands.

The island also has a caldera, a large cauldron like hollow that forms shortly after a volcano empties its magma chamber. Greece’s Climate Crisis and Civil Protection Ministry said this week sensors had picked up ‘mild seismic-volcanic activity’ inside the caldera but scientists have since said the quakes are not linked to the activity. They also say there’s little chance of a volcano eruption any time soon.

Yes, earthquakes have struck several islands. As mentioned before they tend to be relatively mild, but there have been the a few relatively serious quakes over the years. The region of the Ionian Sea, including the islands of Lefkada, Kefalonia, Ithaca, and Zakynthos tend to experience the strongest tremors. In 2015 an earthquake that struck Lefkada left two people dead, dozens injured and caused property damage costing millions of Euros.

Kefalonia, Zakynthos and Ithaca were hit by a massive 6.2 quake in 1953 which destroyed 27,569 homes out of the 33,000 residences on the three islands. The area from southern Crete to Rhodes is also more prone to higher magnitude quakes due to a geological formation called the Anatolian Rift. It’s very difficult to predict how long the earthquakes will last and, as a result, when the state of emergency will come to an end.

But authorities have said activity could go on for weeks. Experts are also unsure whether the series of quakes are foreshocks leading up to a large earthquake or just a swarm of smaller quakes. Get in touch with our news team by emailing us at webnews@metro.co.uk. For more stories like this, check our news page. Arrow MORE: ‘I’m a British expat in Santorini – here’s why I’m staying put despite evacuations’.