A pendulum … for centuries has ended, according to scientists, the powerful earthquake that killed Turkey’s Elazig last week: The point at which the 6.8 Richter rock was triggered on the night of January 24 was the only part of its crack East Anatolia – a rift with a total length of 470 km – that had never been broken in history. It was a “seismic vacuum”, as the researchers call it, which was all expected to “break” by producing a powerful earthquake, but no one knew when …

Corresponding “seismic gaps” are also found in Greece and specifically in the Central Ionian Sea, which have remained “silent” for at least 37 years despite the strong seismic activity in the area around them. The Ionian Seismic Gaps were fully mapped in 2016 in a study using space geodesy data and published in international scientific journals led by Seismologist and Geodesy Research Director Dr Athanasios Ghana.

“Key to Forecasts”

“The earthquake in Elazig closed the seismic gap that existed along the eastern Anatolian rift,” Dr. Ghana explains to the NEWS. “This rift consists of seven tracks, each 50 to 100 kilometers long, that break apart independently and produce earthquakes measuring 6 to 7.5 magnitude. The previous major earthquake had occurred in the Bingol area – about 100 kilometers to the east – in 2010 at a magnitude of 6.1. The section of the ridge that broke south of Elazig on January 24 with a magnitude of 6.8 was the only one for which we had no historical record so it was a “seismic gap”.

 

This confirms the theory of “seismic vacuum” and proves that it is a key to predicting future cracks on large cracks in the planet as long as their seismic history is known, which can be obtained by combining geological and seismological methods. ” , he adds.
Likewise, scientists have been able to identify where the next major Ionian earthquakes are likely to occur. These are three fragments of large cracks that did not “break” during recent strong earthquakes: The first 6km long “seismic gap” is located along the west coast of Lefkada; the second, 14km long, is northwest of Kefalonia. and the third with a length of 30 km was recorded on the west coast of the island. According to experts, these points can give earthquakes of 5.5 to 6.5 Richter intensity and although it is not easy to predict their behavior it is expected that these points will break within the next 20 years.

The mapping

“Because we do not have paleoseismological data for the Ionian Sea, this gap has been filled by space-time data,” says Dr. Gananas, describing the process he and his team have undertaken in the case of the Central Ionian Sea. “Using this data, we mapped in detail the soil deformation that had occurred in the area from four older strong earthquakes,” he says. It was the seismic vibrations of August 14, 2003 that hit Lefkada with 6.2 earthquakes, the magnitude 6.1 and 6 earthquakes that occurred in Kefalonia in January and February 2014, and the 6.5 magnitude vibrations that occurred in Kefalonia. Lefkada in November 2015. Before them, an earthquake of 6.8 magnitude caused an earthquake in 1983 in the marine area southwest of Kefalonia.

Although the exact boundaries of the cracks that caused these earthquakes were not known as they had no surface manifestations. The satellites revealed their boundaries and then identified “seismic gaps” between successive breaks. These gaps are believed by seismologists to be “filled” with burglaries, and consequently earthquakes, in the coming years.
It is noted that the frequency of earthquakes in the Central Ionian Sea is about 40 years. Scientists are using verified scientific data to identify “seismic gaps” as earthquakes known from historical records cannot accurately identify the focus.

Ground shift from the earthquake in Turkey

The earthquake caused a dramatic shift in Turkey on January 24, 2020. According to measurements by researchers at the Athens Institute of Geodynamics, the ground on either side of the rift was displaced by … 70 cm while the total length of the rupture was 40 mm. The total area of ​​deformation is 350 square kilometers, with smaller displacements. The findings came from an analysis of satellite data carried out by researchers at the Institute of Geodynamics Sotiris Balkaniotis, Athanasios Ganas and Barbara Tsironis.

source -in.gr