ATHENS, Greece (AP) 鈥 Multiple earthquakes are rattling Santorini, a volcanic island in Greece, prompting authorities to dispatch rescuers with tents, a sniffer dog and drones, and to shut schools on four islands.
Last week, scientists said they noticed increased volcanic activity in Santorini's caldera, or flooded crater, but say the current earthquakes are unrelated.
to avoid indoor gatherings, check escape routes, stay away from cliffs and to drain swimming pools to reduce potential structural damage to buildings in the event of a large earthquake.
Greece lies in a highly , and earthquakes are frequent. The vast majority cause no injuries and little or no damage, but the country has also seen deadly quakes.
Santorini, one of Greece鈥檚 most popular tourist destinations, took its present crescent shape following a massive volcanic eruption in antiquity. Now, millions of visitors each year come to see its dramatic scenery of whitewashed houses and blue-domed churches clinging to the caldera rim.
Here鈥檚 a look at the current situation:
What's going on?
Hundreds of quakes with magnitudes between 3 and 4.9 have been registered since Saturday between Santorini and the nearby island of Amorgos. Although Greece is no stranger to earthquakes, seismic activity of such frequency and intensity without having been preceded by a major quake is unusual, seismologists say.
The fault line producing the earthquakes runs for about 120 kilometers (75 miles), but so far only part of it, between the islands of Santorini and Amorgos, has been activated. The epicenters are beneath the seabed, which scientists say is good news, as quakes centered beneath land could potentially be more destructive.
But a large quake could also trigger a tsunami, so authorities have warned people to stay away from coastal areas and head inland if they feel a significant earthquake.
So far, there has been no significant damage and no injuries, although some minor rock slides have occurred.
Could the earthquakes trigger a volcanic eruption?
Although theoretically possible, experts say they don't expect that.
鈥淎ll scientists agree that this is a highly unlikely scenario,鈥 Costas Papazachos, professor of applied geophysics and seismology at the University of Thessaloniki, said Tuesday.
Santorini lies along the Hellenic Volcanic Arc, which stretches from the Peloponnese in southern Greece through the Cycladic islands. There are two volcanoes in the area: Nea Kameni, an islet within Santorini鈥檚 caldera; and Kolumbo, a submarine volcano about 8 kilometers (5 miles) northeast of Santorini.
Last week, Greece鈥檚 Climate Crisis and Civil Protection Ministry announced that sensors had picked up 鈥渕ild seismic-volcanic activity鈥 inside the caldera. Similar activity in 2011 lasted for 14 months and ended without any issues.
Scientists say the current quakes are unrelated to the volcanic activity.
What are authorities worried about?
Experts are still trying to determine whether the multiple quakes are foreshocks 鈥 smaller earthquakes before a major temblor 鈥 or whether they are part of an earthquake swarm of smaller quakes that could continue for weeks or months.
鈥淭here is no serious technology or approach to be able to predict what will happen from here on,鈥 Papazachos said.
Seismologist Gerasimos Papadopoulos said that the 鈥減ossibility is open鈥 that the quakes, which began on Jan. 24 and intensified Saturday, could be followed by a larger temblor.
Santorini鈥檚 main villages are built along the rim of the volcano鈥檚 caldera 鈥 producing the dramatic scenery of cascading whitewashed houses and sunset viewpoints that make the island so popular, but also raising concerns in the event of a major earthquake. The sheer cliffs also make some areas prone to rock slides.
What precautions are being taken?
Authorities sent rescuers with a sniffer dog and drones to Santorini, where they set up tents in a basketball court next to the island鈥檚 main hospital as a staging area. Push alerts have been sent to cellphones warning people to stay away from areas where rock slides could occur, and banning access to some coastal areas.
Residents and hotels have been asked to drain swimming pools, because the water movement in a major quake could destabilize buildings. People have been told to avoid old buildings and check for exit routes when in built-up areas.
Schools on Santorini, as well as the nearby islands of Anafi, Amorgos and Ios, will remain shut all week, while other nearby islands also shut their schools on Tuesday.
What's the history?
Greece鈥檚 largest quake in the last century occurred in the area 鈥 it was a 7.7-magnitude temblor dubbed the Amorgos earthquake that struck in 1956, triggering a roughly 20-meter (65-foot) tsunami, causing significant damage in Amorgos and Santorini and killing more than 50 people.
Santorini is also the site of one of the largest volcanic eruptions in human history. Known as the Minoan eruption, it occurred around 1,600 B.C. and destroyed much of the formerly round island. The eruption is believed to have contributed to the decline of the ancient Minoan civilization.
Although still an active volcano, its last notable eruption occurred in 1950.
鈥淲hat we must realize is that the Santorini volcano produces very large explosions every 20,000 years,鈥 Efthymios Lekkas, seismologist and head of the scientific monitoring committee for the Hellenic Volcanic Arc, said last week. 鈥淚t鈥檚 been 3,000 years since the last explosion, so we have a very long time ahead of us before we face a big explosion.鈥
