A total of 6,400 earthquakes were registered at the Santorini (Thera) and Amorgos islands region between January 26 and February 3, the University of Athens' Interdisciplinary Committee of Handling Threats and Crises said on Wednesday.
According to an updated analysis of seismic activity up to February 3, over 1,300 earthquakes occurred on February 2 and over 1,400 on February 3.
The committee also noted their rising intensity, from January's 2.5 on the Richter scale to three earthquakes measuring from 4.9 to 5.0 on the Richter scale between February 3 and 4.
As of February 2, seismic activity began concentrating between Santorini and Anydros, an islet belonging to the municipality of Amorgos, before moving closer to Anydros and no more than 10 km from it. The shifting location at the islet appears to be happening with accelerating speed and covering smaller distances, while the frequency of earthquakes has increased.
Earthquake swarm?
The committee's announcement said the seismic activity appears to have the features of an earthquake swarm, "as there is no distinguishing earthquake with clearly higher intensity than the rest that could be identified as the main earthquake." The committee also said it was possible the activity could continue at gradually lower intensities and last many months, as in the case of an earthquake swarm at Thebes. Alternatively, this activity could cause the rupture of a great section in a large and active fault in the region, causing a main earthquake followed by a typical post-earthquake sequence, it noted.
In its statement, the committee said that despite the fact the spate of earthquakes is happening within an active volcanic arc in the South Aegean, "it is not directly related to some known volcanic center, but appears to have activated a system of normal faults in southwest-northeast direction at the marine basin of Anydros."
Members of the University of Athens' Seismology and Geophysics Labs and of the committee will travel to Ios and Santorini to install and maintain seismographers and to measure the ground deformations.