Santorini volcano, whose eruption 3,600 years ago wiped out Minoan settlements on the Greek island and in Crete, has begun to fill with molten rock and expand the most since its last eruption from 1939 to 1941.

The chamber of liquid rock, or magma, beneath the volcano expanded by 10 million to 20 million cubic meters from January 2011 to this April, a University of Oxford-led team wrote in the journal Nature Geoscience. That’s as much as 15 times the size of London’s Olympic Stadium, the university said separately.

Santorini, a popular destination for cruise ships including Royal Caribbean Cruises Ltd. and Carnival Corp., was devastated by the Minoan eruption and now forms a steep-walled arc in the Aegean Sea. While no imminent eruption is suggested by the data, it can’t be ruled out, the authors said.

Studies at the volcano “strongly suggest that the present episode of volcanic inflation is the only significant one since the eruption of 1939-1941, or shortly thereafter,” the researchers wrote. “It would be unwise to assume that the present state of unrest will not end in an eruption.”

The expansion of liquid rock has pushed Santorini up by 8 to 14 centimeters (3 to 5.5 inches), according to the university. The scientists used satellite radar images and Global Positioning System data to calculate the shift.

Santorini alternates between explosive eruptions that occur every 10,000 to 30,000 years and smaller, more frequent dome- forming eruptions separated by as little as 14 years, according to the paper. The volcano had its last “significant” eruption about 70 years ago, the authors said.

“If the present rate of inflation were to continue for a small number of years, the intruded volume would be equivalent to the volumes of previous eruptions,” the researchers said.

The volume of molten rock that’s accumulated since the start of 2011 amounts to as much as 50 percent of the amount expelled during Santorini’s smaller eruptions, they wrote. The increased activity began with three small earthquakes in January 2011 and has subsided since April, they said in the statement.

Others say that’s a sign an eruption may not be imminent.

All anomalous tremors, deformation of land, chemical releases and heat measurements have subsided this year, Georges Vougioukalakis, a volcanologist with the Institute of Geology and Mineral Exploration in Athens, said Monday in an e-mail.

“Now all registered activity is that of the ‘normal’ dormant state of the volcano,” Vougioukalakis said. He wasn’t an author on the paper Monday. [Bloomberg]