Athens University recorded more than 14,000 tremors between January 26 and February 9 at sea between the islands of Santorini, Amorgos, Ios and Anafi.

The activity has baffled scientists but has so far caused no damage or injuries.

A businessman from Santorini, speaking on Skai TV on Sunday, said the island's tourism industry is already being damaged.

"At this time of the year, all the shops were full of people coming with the cruises. Now, which company will take the responsibility to bring a cruise ship close to the island?" he said.

Santorini attracted about 3.4 million visitors in 2023, with upwards of a million of those from cruise ships, making it one of Greece's most visited spots.

Mitsotakis in a social media post acknowledged that the tremors "cause financial damage to workers and businesses", announcing "special measures" to support them.

He said that all private sector businesses operating on Santorini and the nearby island of Amorgos, which has also declared a state of emergency, can suspend salary payments from February 1 to March 3, 2025.

"Employees whose employment contracts are suspended will receive a special-purpose compensation of 534 euros, corresponding to 30 days," he added, provided their employers pledge to maintain job levels.

"We will stand by our islanders as long and as much as necessary", he concluded.

The prime minister also announced that "schools in Thira, Ios, Anafi, and Amorgos will remain closed until Friday, February 21". The schools first closed two weeks ago.

The majority of Santorini's nearly 16,000 residents have left the island.

Amorgos, which has fewer than 2,000 permanent inhabitants, is considered less at risk owing to its rockier terrain and less dense construction than Santorini.

Santorini lies atop a dormant volcano which last erupted in 1950.

Scientists say that the region has not experienced seismic activity on this scale since records began in 1964.

Last Monday, Tourism Minister Olga Kefalogianni discussed the strategy and best measures for dealing with the emerging challenges for the tourism sector during a meeting with island groups and associations.

"Santorini is an iconic Greek tourism destination and it is our priority to ensure its stability and competitiveness", she said.