An earthquake of magnitude 4 on the Richter scale occurred at 11:21 a.m. 18 km north of Santorini. Three hours earlier, 150 km from Santorini, near the island of Nisyros, there was another shock with a magnitude of 4.4 points.
According to the Geodynamic Institute of the National Observatory of Athens, the epicenter of the earthquake is located in the sea area 18 km northwest of the city of Santorini. Its focal depth was 10 km. According to seismologists, this activity is associated with the underwater volcano Columbo, operating in the Santorini region. The main shock was followed by aftershocks with a magnitude of 3.4 points.
Columbo was discovered in 1649-1650. due to the “violation” of the sea surface. Its power was incomparable with the well-known Minoan eruption of Santorini. This explosion, which occurred as a result of the accumulation of magma under the dome, was unforgettable. When it happened, a pyroclastic flow rolled down the slope and after a few seconds found itself on the coast and slopes of the Tyra caldera, where more than 70 people and a huge number of animals (more than 1000 individuals) died as a result. After the explosion, the volcano fell into the caldera, causing damage to nearby islands at a distance of 150 km. The height of Columbo after the disaster decreased by ten meters. From that time on, he stopped erupting, but his seismic activity did not stop.
According to research carried out in 2010 by the scientific vessel EV Nautilus, the volcano has 19 craters with a depth of 18-450 meters. During the 2006 expedition, a field of active hot springs was discovered in the volcano field at a depth of 500 meters (their temperature reaches 224 ° C), where a pyrite deposit of the Kuroko subclass is currently being formed. Only a handful of such deposits have been found in the oceans, and they are of great interest due to their higher gold and silver contents compared to the mid-ocean ridge hydrothermal vents known as black smokers.
Earthquake near Nisyros happened at 08:09 am. According to the Athens Geodynamic Institute, tremors are estimated at 4.4 on the Richter scale. The epicenter is located 14 km south of the island, the focal depth, according to updated data, is 15 km. Following the first, most powerful shock, more than 15 aftershocks with magnitude up to 3 points occurred.
Earthquake data comes from the Geodynamic Institute of Athens or the Euro-Mediterranean Seismological Institute. They are recorded by an automatic computer system, without the participation of seismologists, and are in the process of constant updating.