Samos Shakes Again

Two earthquakes were recorded within minutes near Samos in the eastern Aegean on Wednesday afternoon.

The Geodynamic Institute of Athens gave preliminary estimates of 4.3 and 4.2, with the first shock at 14:14, 42 km northeast of the island (the focal point was in Turkey), and the second at 14:18, at 28 km north-east of Samos. The focal depth was 14 and 24 kilometers, respectively.

No damage was reported, but both shocks were felt on the island. Its inhabitants still have not moved away from the strong earthquake that occurred on October 30, 2020. Then as a result earthquakes with a magnitude of 6.7 killed two teenagers, who were crushed by the collapsed wall of an abandoned house. In the neighboring Turkey the consequences were even more tragic – more than 60 people died during this earthquake.

After the catastrophic earthquake in Erzincan in 1939, seven earthquakes with a magnitude of more than 7.0 were recorded, the epicenter of which gradually moved further and further west. Seismologists who follow this pattern believe that one earthquake can cause the next. By analyzing the trends caused by the last major earthquake in the rift, seismologists predicted the next one that hit the city of Izmit with disastrous results in August 1999. In fact, the chain is considered incomplete, and the earthquake will occur further west of the rift, in Constantinople.

Some of the strongest earthquakes in northern Anatolia are:

1939 Erzincan, 7.8 Richter, 32,700+ killed and more than 100,000 wounded 1942 Nixar-Erbaa, 7 Richters, ~ 3,000 killed 1943 Tosya-Ladik, 7.2 Richter, 2824 killed 1944 Bolu-Gerede – 7.2 Richter, 3959 killed 1949 Karlev, 6.7 Richter, 320 killed 1951 Kursunlow, 6.9 Richter, 50 killed and 3354 wounded 1957, Abad, 7.1 Richter, 52 killed 1966 Varto, 6.9 Richter, 2394 killed and 1,489 wounded 1967 Mountourno Valley, 7.1 Richter, 86 dead, 332 wounded 1992 Erzincan, 6.7 Richter, 498+ dead, at least 2,000 wounded 1999 Izmit, 7.6 Richter, 17 118+ dead and 43 953+ injured 1999 Duzce, 7.2 Richter, 845+ dead and 4948 injured.

19 major active faults in the Aegean Sea that threaten Greece

The bottom of the Aegean Sea between Skyros, the island of Mytilene and Agios Efstratios hides a total of 19 large active faults more than seven kilometers long each, which can cause strong earthquakes of magnitude 6.1 to 7.4 on the Richter scale. In fact, eight of them can “give” earthquakes of more than 7 points on the Richter scale.

Of the 19 active events that were first mapped a few years ago, only three were known in recent decades and are included in seismic lists. Since their discovery, scientists have believed that “the area’s potential seismic risk has been underestimated” and that “these faults can cause massive earthquakes that could wreak havoc on the surrounding islands.”

According to the estimates of the researchers who made the corresponding publication in the journal “Marine Geology”, in addition to Agios Efstratios, an earthquake of magnitude 7.1, as a result of which 20 people died in 1968 and the reactivation of which takes several centuries, as well as three more faults that “gave smaller earthquakes in the last 30 years, the remaining faults could cause a strong earthquake with a magnitude of 6.1 to 7.3. But it is still impossible to determine whether this will happen in a few years or in decades.

The almost triangular Skyros basin, whose depth ranges from 600 to 1050 meters, has a tectonic structure. Similar to the structure of the neighboring North Aegean Basin, but with a smaller size and slower deformation rates. The activation of faults in the area of ​​the Skyros depression and the beginning of the subsidence of this area began quite recently, several hundred thousand years ago. Therefore, at the bottom of a shallow platform around the depression, one can see the old background and only a few modern deposits of several tens of meters.

Scientists are trying to map underwater faults in great detail in order to know their potential and the magnitude of the earthquake they can cause. The bottom of the Skyros Basin was surveyed by the oceanographic vessel Marine Geology in 2002, 2003 and 2013. Among other finds, it was found that the total displacements in the faults are on the order of one to one and a half kilometers, with the formation of underwater rocks several hundred meters high.

In addition to the 7.1 magnitude earthquake on February 19, 1968, with an epicenter near Agios Efstratios (which caused a small tsunami to the island of Lemnos), other major earthquakes in the area occurred on March 4, 1967 in the Skyros basin (6.2 points) and December 19, 1981 in the eastern part of the same basin (6.8 points), which caused more damage in Mytilene than in Skyros. This was followed by strong aftershocks with the highest score of 6.3 points out of 27 points. On July 26, 2001, a few kilometers southwest of Skyros, an earthquake of 6.4 magnitude occurred at a depth of 13 km.





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