Greece faces unprecedented seismic crisis as thousands of earthquakes shake Santorini

According to its recent article, BBC describes that the island of Santorini in Greece is currently experiencing a series of unprecedented seismic events, with thousands of earthquakes shaking the region. 

The resident of Santorini is concerned about the impact of the ongoing earthquakes on the Greek island, which is renowned for its stunning, postcard-perfect views.

"We've put all our mattresses in the living room," says Georgia Nomikou.

However, the peaceful setting has been shaken this past week by a series of thousands of earthquakes.

Santorini, along with other Greek islands in the area, is currently experiencing an "unprecedented" seismic swarm—a sudden increase in earthquake activity in a specific region.

Around three-quarters of the island’s 15,000 residents have evacuated, and authorities have declared a state of emergency after a 5.2 magnitude earthquake, the strongest so far, struck the island recently.

Further, albeit smaller, tremors were also felt.

These "clusters" of earthquakes have baffled scientists, as they are unusual because they have not been followed by a major earthquake. So, what is happening?

Experts agree that the island is facing what Greece's prime minister has described as an "extremely complex and intricate geological phenomenon."

"It is really unprecedented; we have never seen something like this before in [modern times] in Greece," says Dr. Athanassios Ganas, research director at the National Observatory of Athens.

Santorini is situated on the Hellenic Volcanic Arc—a group of islands formed by volcanic activity.

However, it hasn't experienced a significant eruption in recent times, not since the 1950s, making the cause of the current seismic crisis unclear.

Experts point out that they are observing numerous earthquakes within a relatively small area, which do not follow the typical pattern of a mainshock-aftershock sequence, according to Dr. Ganas.

He explained that the sequence began with the awakening of a volcano on Santorini last summer, followed by a "surge" in seismic activity in January, with smaller quakes recorded.

The activity has intensified over the past week.

"We are in the middle of a seismic crisis," Dr. Ganas stated.

Dr. Margarita Segou from the British Geological Survey noted that the quakes occur daily "in pulses."

She explained that this "swarm-like behavior" means when a more significant earthquake occurs, such as a magnitude four, the "seismicity increases for one to two hours, then the system relaxes again."

In short, it is impossible to predict. Authorities have cautioned that the activity could continue for weeks.

Experts also remain uncertain whether this sequence of quakes is a series of foreshocks leading up to a major earthquake or if it is an event of its own.

Professor Joanna Faure Walker, an expert in earthquake geology at UCL's Institute of Disaster Risk Reduction, explained that some large earthquakes do have foreshocks—elevated levels of smaller to moderate seismic events—before the main shock.

But according to Dr. Ganas, what is happening now are not volcanic earthquakes. Volcanic earthquakes have a distinct signature with low-frequency waveforms, which have not been observed here.

Dr. Segou told the BBC that she and her colleagues had used machine learning, a data analysis method capable of making predictions, to analyze past earthquakes in the region, specifically from 2002 and 2004, in order to understand how those seismic events ended.

While the magnitude of those previous earthquakes was not as intense as the current ones, she explained that the "signatures" of how they began and concluded could help identify patterns to watch for now.

In the meantime, additional police units and military forces have been sent to the island to assist with any potential major earthquake.

Ms. Nomikou, president of Santorini's town council, mentioned that her family is staying on the island, but each member has packed a small bag, "ready to go if anything happens."

However, some islanders are not overly concerned by the tremors.

"I'm not afraid at all," says one Santorini resident who decided to remain on the island, even as thousands of her neighbours evacuated amid the ongoing earthquakes.

Chantal Metakides firmly stated that she would not follow the crowd. "For 500 years, this house has lived through earthquakes and volcanic eruptions and it's still standing," she told AFP, adding, "there's no reason why this should change."

By Naila Huseynova