The first geological map of the kind of young replicas in the Sea of ​​Galilee marks the places prone to earthquakes

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So far we have thought that most of the tectonic activity takes place in the eastern part of the Sea of ​​Galilee, on a replica of the Dead Sea. We now know that the replica splits and passes through the middle of the Sea of ​​Galilee, so it can be assumed that earthquakes on this replica will also affect the west coast, “said Dr. Michael Lazar of the Charney School of Marine Sciences at the University of Haifa, who led the study.

Michael Lazar and Naama Sarid (University of Haifa) install the sonar device on the boat in the Sea of ​​Galilee. Photo: Luca Gaspirini

A new study by researchers from the University of Haifa, in collaboration with researchers from Italy, Switzerland and Norway, maps for the first time the “shallow” geological replicas in the Sea of ​​Galilee – from the bottom of the lake to a depth of 2 km – and points to the northern region. The journal SCIENTIFIC REPORTS. “The findings of the study indicate that there are active replicas throughout the length and breadth of the Sea of ​​Galilee, and not just in the eastern region as previously thought. This means that the possible effects of earthquakes on these replicas could reach all the banks of the Sea of ​​Galilee, “said Dr. Michael Lazar of the Charney School of Marine Sciences, who led the study.

The Sea of ​​Galilee is a kind of geological mystery. The sediment near the bottom of the lake is saturated with gas, as the gas weeks mask the geophysical signal and in fact do not allow researchers to “see” the geological structure of the shallow subsurface (near the bottom) and the map of young replicas of the shallow subsurface. “Everyone who was in the Sea of ​​Galilee felt the strange feeling of the bottom – from a feeling of mud from which bubbles rise. This is because of the invention of gas within the shallow layer near the bottom. R. Lazar.

Replicas are cracks that form in the rocks of the Earth’s crust due to pressures that cause, in addition, also movement in the rock blocks on either side of the crack, opposite each other. Most earthquakes occur due to this phenomenon, with geological maps knowing not only to map the replicas, but also to mark which replicas are more active in recent years – and therefore, more prone to earthquakes. This is why accurate geological maps are important for managing the risks of infrastructure construction, insurance costs and more.

To address the geological challenge of the Sea of ​​Galilee and to draw an accurate geological map, the researchers, Dr. Lazar from the Charney School of Marine Sciences in Haifa, together with researchers from Italy, Switzerland and Norway, chose a number of methods that complemented each other: they placed 12 seismic stations Very sensitive measured for a year small earthquakes around the Sea of ​​Galilee; Check the geochemical composition of the springs around the Sea of ​​Galilee – the chemical composition of the water can give an indication of whether they come from a deep or shallow source; Conducted a high-resolution seismic survey using sonar in the center of the Sea of ​​Galilee; Reworked old data from 1997 from surveys of deeper layers, in which there are no springs of gas (depth of about 2.5 km).

Using the various methods, the researchers were able to draw for the first time 19 young replicas below the bottom of the Sea of ​​Galilee, ten of which are deep replicas. “Deep replicas are replicas that break the bottom of the lake and mean that these are replicas that have been relatively active in recent years. Replicas that have no expression on the bottom are ones that have probably not been active in decades or even centuries,” Dr. Lazar said. Researchers in an area north of the Sea of ​​Galilee that has been more tectonic in recent years – which raises the likelihood of earthquakes occurring in this area.

Also, contrary to what has been thought so far, the researchers found that the Dead Sea fragment entering the Sea of ​​Galilee on its eastern side splits in two – with one replica continuing on the eastern side while the other continues along the center of the lake. “Until now we thought most of the tectonic activity took place in the eastern part of the Sea of ​​Galilee, on a replica of the Dead Sea. Therefore, the assumption was that earthquakes on the east side would not affect the West Bank. We now know that a replica passes in the middle. On the west coast – and expect more earthquakes that will also affect the west coast, “said Dr. Lazar.

More on the subject on the Yadan website:
The risk of strong earthquakes in the eastern Mediterranean is higher than previously estimated
Physicists from the Hebrew University have formed a new understanding of the process of friction that causes earthquakes
Historical Review – The strongest earthquakes in our region to date

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