The Greek island of Santorini was placed in a state of emergency after having known its strongest earthquake according to the days of continuous tremors.
An earthquake of magnitude 5.2 struck Santorini on Wednesday evening, the first to exceed 5.0 since the start of the tremors last week. Thursday, two larger tremors shook the island, each exceeding a magnitude of 4.0.
Santorini’s latest major earthquake, a magnitude 7.5 tremor in 1956, killed at least 53 people.
Here is what we know so far:
What’s going on in Santorini?
The island, one of the Cyclades of Greece in the Aegean Sea, has experienced almost constant tremors since January 27, 2025, with thousands of earthquakes recorded so far.
The most powerful earthquake since then – occurring Wednesday evening – recorded an amplitude of 5.2 on the Richter scale.
The magnitude measures the size of an earthquake with increments represented by decimal points. An earthquake of size 6.0 or more is classified as severe, while an amplitude of 5.2 is considered moderate.
Santorini is located along the Hellenic volcanic arc, which extends from the Peloponnese of southern Greece through the Cyclades Islands. The region also houses two volcanoes: Nea Kameni, a small island inside the Caldera de Santorini, and Kolumbo, an underwater volcano located about eight kilometers (five miles) in the northeast of the island.
The swarm of the earthquake of Santori-Amorgos continues to continue. He has now produced more than 1,000 individual events since his start on January 27. pic.twitter.com/kqwxj0vbb
– Nahel Belgherze (@wxnb_) February 5, 2025
Where are the epicenter of earthquakes affecting Santorini?
Earthquakes are concentrated in a growing cluster between the Santorini, Aafi, Amorgos and iOS islands. The seismic activity remains concentrated between Santorini and the neighboring island of Amorgos.
The epicentres are located under the foundations, which is good news; According to scientists, earthly earthquakes generally cause greater destruction. Greece lies in a highly seismic part of the world and earthquakes are not uncommon.
What are the main concerns?
The authorities make preparations in the event of an even greater earthquake because the tremors show no signs of softening. On Wednesday, the authorities warned against the risks of landslide in certain parts of the island.
“We are not yet able to say that we see evidence that would lead to the sequence at the conclusion,” Vassilis K Karastathis, seismologist and research director at the National Observatory of Athens, told Athens.
“We are still in the middle of the road, we have not seen any softening, no sign that he is heading towards a regression.”
Earthquakes have not caused major injuries or damage. According to reports, more than 11,000 people left Santorini following the tremors. According to the 2021 census, Santorini, which is popular with tourists, has a permanent population of 15,000 inhabitants.
Could earthquakes cause a volcanic eruption?
Although Santorini is near two volcanoes, the experts consider an unlikely eruption. Scientists point out that current earthquakes are not linked to volcanic activity and do not pose specific volcanic risk.
Last week, the Ministry of Greece of the climate crisis and civil protection said that the sensors detected a “slight seismic-volcanic activity” in the Santorini caldera. A similar event in 2011, however, persisted for 14 months without causing volcanic problems.
“Right now, I don’t think there is a danger of the Kolumbo’s underwater volcano and the volcanic complex … However, I should say that we cannot exclude the arrival of a second magma impulse, And [if so] This episode will repeat itself, “said Al Jazeera Athanassios Ganas, research director of the National Observatory of Athens.
However, the island has a long history of volcanic activity. Around around 1,600 BC, one of the most massive volcanic eruptions in human history has shaped the Santorini in its current geological form.
Between 2011 and 2012, the island underwent an important seismic activity due to the movement of magma below the surface.
Will the tremors continue for a long time or will they get worse?
“We cannot exclude the possibility of having an earthquake of about 6.0 on one of the neighboring faults,” Ganas told Al Jazeera.
“Because all these seismicity transfer stresses to neighboring defects which are long enough, about 15 kilometers, and this fact means that they have the potential of an earthquake of magnitude 6.0”, he Added.
However, Ganas stressed that this is not the most likely scenario. “This is the second in priority. The first scenario is that we are in the midst of a seismic swarm, “he said.
A seismic swarm is a series of many small to moderate earth tremors occurring in a localized area over a short period, ranging from hours to month, without only one dominant main time.
How do Greek authorities react?
Greek Prime Minister Kyriakos Mitsotakis is expected to visit Santorini on Friday.
Local authorities closed schools until Friday in Santorini and Amorgos, sent rescuers and advised residents to avoid ports and indoor gatherings.
The government said that the state of emergency would remain in place until March 3 to enable it to meet the needs of the population and the consequences of seismic activity.
