As Santorini shakes, scientists measure, analyze and hypothesize

Santorini is built on shaking ground. The picturesque Greek island is a caldera, or collapsed volcano, formed by an eruption 3,600 years ago. 

But over the last two weeks, thousands of small earthquakes have suggested that seismic shocks may not be a thing of the distant past.

On Monday, scientists, experts and even military personnel gathered at the island's port, bringing out some serious high-tech equipment to keep an eye on Santorini's volcano. And even the pros are admitting this level of activity is beyond their personal experience.

"I haven't experienced something like this before," marine geophysicist Jens Karstens tells CGTN. "In the last 15, 25 years, there were two previous events with increased earthquake activity here at Santorini and around Santorini. However, this event is larger than what was experienced before. 

"And just to give perspective, the two last events happened and basically nothing – the activity calmed down and no peak earthquake appeared or no peak or no eruption at all. So this is an option for this unrest as well. However, we need to be prepared that the option that it might be a large earthquake or a kind of eruption is real."

The problem is that this is a phenomenon unlike anything the experts have dealt with before. Even with all the latest tools and sensors, figuring out exactly what's going on—and how long it'll last—is going to take time.

"We can say for sure that we can't say anything for sure," says Karstens. "As a scientist, it's always very difficult to rule out scenarios. 

"We have a limited database and we're getting more and more data, so our ideas are getting better with time. Right now we actually need to wait and see how the situation develops."

Scientists divided

This phenomenon is so unusual that scientists are divided. Some say the tremors are connected to the submarine volcano Kolumbo, just eight kilometers north-east of Santorini; others dispute that theory. 

What they agree on is that they are in uncharted waters – making it impossible to say for certain what will happen next.

"All the seismic activity that occurred during these days has nothing to do with the Khomeini area and the submarine volcano Kolumbo," volcanologist Evi Nomikoy tells CGTN. "But this is a very unique geological phenomenon. 

"So we need to analyze and to have in our hands all the data – seismic data, physical data, geodetic data, gravity data – in order to make a synthesis of all of the data and to understand this phenomenon."

Scientists are tracking every rumble, every shift, but there's no crystal ball for what happens next – or when. Santorini's shaky ground has a history of surprises, and while experts are hoping this is just another restless phase, there's always the chance Mother Nature is gearing up for something bigger.