Successive earthquakes were recorded during the night in the sea area south of Amorgos, the strongest of which had a magnitude of 5.0 on the Richter scale, according to data released by the Geodynamic Institute of the National Observatory of Athens.

It was preceded by a 5.3-magnitude earthquake that also shook Athens at 10:16 PM on Monday (10/02), the largest recorded since the beginning of this seismic activity.

On the morning of Tuesday (11/02), at 9:17 AM, a new 4.8-magnitude earthquake occurred 14 kilometers southwest of Arkesini, Amorgos, with a focal depth of 16.4 kilometers, according to the Geodynamic Institute.

At 8:39 AM, a 4.6-magnitude tremor was recorded 11 kilometers southeast of Arkesini, Amorgos, with a focal depth of 15.2 kilometers.

Another earthquake followed at 7:58 AM, with a magnitude of 4.8 Richter, occurring in the sea area 12 kilometers south of Arkesini, Amorgos, with a focal depth of 16.2 kilometers.

A 4.0-magnitude tremor was recorded just after 7:36 AM, 26 kilometers south of Arkesini, with a focal depth of 12 kilometers. A few minutes later, at 7:43 AM, another 4.2-magnitude tremor was recorded 16 kilometers southeast of Arkesini, with a focal depth of 13.6 kilometers.

Earlier, a 4.4-magnitude earthquake was recorded at 7:14 AM, 233 kilometers southeast of Athens. According to the Geodynamic Institute of the National Observatory of Athens, its epicenter was in the sea area 15 kilometers south-southwest of Arkesini, Amorgos.

The other recorded seismic tremors, three of 4.0 magnitude, one of 4.1, and the strongest of 5.0 magnitude, were recorded in reverse chronological order at 5:47 AM, 2:02 AM, 12:51 AM, 12:44 AM, and 12:37 AM, according to the same source. Their epicenters were located in the sea area between 16 and 18 kilometers south of Arkesini, Amorgos, based on institute data. Except for the 5.0-magnitude tremor at 12:37 AM, which is considered "strong," all others were classified as "weak."

At 10:16 PM on Monday, the strongest tremor in the Cyclades region's seismic sequence so far was recorded, with a magnitude of 5.2 Richter.

What Seismologists Say About the New Strong Earthquakes

Speaking to ANT1 on Tuesday morning (11/02), seismology professor Dimitris Papanikolaou commented on the recent tremors: "Seismic activity continues to show significant movement with moderate earthquakes, with small faults breaking throughout the zone. There remains a possibility—not many, but enough—for the excitation of the large Anydros fault, which, as we have said, could produce a magnitude 6 earthquake."

When asked if this was the main earthquake, Papanikolaou stressed: "I do not see any indication that we are dealing with the main earthquake at 5.2 or 5.3. It is clear that the main earthquake has a ceiling of 6.0 magnitude. Only when we reach something around 5.8 – 5.9 – 6.0 – 6.1 will we be able to confirm the main event. As long as we remain below 5.5, we cannot talk about a main earthquake."

Regarding the expected duration of the seismic activity, he added: "This moderate activity, as long as it persists without the larger earthquake we expect, will last at least until Easter and possibly beyond. Comparing with similar geodynamic cases that appear to be linked to deep magma movement—not a volcano, but magma at a depth of 4 to 5 kilometers—these situations tend to last for months."

Meanwhile, Efthymios Lekkas, president of OASP (Organization for Earthquake Planning and Protection), told ERTNews: "We cannot say with certainty that this was the main earthquake for the strongest tremor recorded on Monday night."

Seismology professor Kostas Papazachos stated: "This sequence will continue, and in fact, with this same pattern... It will take weeks for this phenomenon to subside. The local community must adapt, and we must operate under the assumption that the entire month of February will continue with a similar situation."

Seismic Risk Committee Convenes

Today, the Seismic Risk Committee is meeting to decide on the next steps for specialists. Meanwhile, initial data from the two retrieved seismographs from the area is expected.

A large scientific team is analyzing data from both land-based and underwater seismographs to determine whether there is a connection between volcanic and tectonic earthquakes.

Experts are installing new, state-of-the-art seismographs around the underwater Kolumbo volcano. This represents an unprecedented research mobilization aimed at analyzing and evaluating the phenomenon.

On February 17, eight new seismographs will be placed near the Kolumbo volcano by an international scientific team arriving on the island.

Due to seismic activity, schools in Amorgos will conduct lessons via remote learning today.