Until now, we thought that most of the tectonic activity takes place in the east of the Sea of Galilee, on the replica of the Dead Sea. Now we know that the replica splits and also passes through the middle of the Sea of Galilee, so it can be assumed that earthquakes on top of this replica will also affect the west coast," said Dr. Michael Lazar from the Charni School of Marine Sciences at the University of Haifa, who led the research
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 copies in the Sea of Galilee - from the bottom of the lake to a depth of 2 km - and points to the northern region as the tectonically active region in recent decades. The study was published in writing SCIENTIFIC REPORTS magazine. "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 can reach all the banks of the Sea of Galilee," said Dr. Michael Lazar from the Charney School of Marine Sciences, who led the research.
The Sea of Galilee is a kind of geological mystery. The sediment that is close to the bottom of the lake is saturated with gas, as the gas clouds mask the geophysical signal and in fact do not allow the researchers to "see" the geological structure of the shallow subsoil (near the bottom) and the map of the young copies of the shallow subsoil. "Everyone who was in the Sea of Galilee felt the strange feeling of the seabed - from the feeling of mud from which bubbles rise. The reason for this is the discovery of gas in the shallow layer next to the seabed. This phenomenon meant that we actually did not clearly know the array of replicas under the Sea of Galilee," said D R. Lazar.
Replicas are cracks that form in the rocks of the Earth's crust due to pressures that cause, in addition, a displacement of the rock blocks on both sides of the crack, relative to each other. Most earthquakes occur due to this phenomenon, when geological maps know not only how to map the replicas, but also to mark which replicas have been more active in recent years - and therefore, more prone to earthquakes. This is why accurate geological maps are important for managing infrastructure construction risks, insurance costs and more.
In order to face the geological challenge of the Sea of Galilee and draw an accurate geological map, the researchers, Dr. Lazar from the Charni School of Marine Sciences in Haifa along with researchers from Italy, Switzerland and Norway, chose a number of methods that complemented each other: they placed 12 seismic stations very sensitive small earthquakes measured for a year 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 it comes from a deep or shallow source; Performed a high-resolution seismic survey using sonar in the center of the Sea of Galilee; Reprocessed old data from 1997 from surveys of deeper layers, where there are no gas emanations (depth of about 2.5 km).
With the help of the various methods, the researchers were able to sketch for the first time 19 young replicas under the bottom of the Kinneret, ten of which are deep replicas. "Deep replicas are replicas that break the bottom of the lake and the meaning is that these are replicas that have been relatively active in recent years. Replicas that have no expression on the bottom are those that apparently have not been active in the past decades or even hundreds of years," said Dr. Lazar. They also identified The researchers are investigating an area in the North of the Sea of Galilee that has been more active in recent years tectonically - which increases the likelihood of earthquakes occurring in this area.
Also, and contrary to what was thought until now, the researchers discovered that the fragment of the Dead Sea that enters the Sea of Galilee on its eastern side splits into two - with one copy continuing on the eastern side while the other continues along the center of the lake. "Until now, we thought that most of the tectonic activity occurs in the eastern part of the Sea of Galilee, on the Dead Sea ridge. Therefore, the assumption was that earthquakes on the eastern side would not affect the West Bank. Now we know that the ridge passes through the middle, which can explain, for example, the strong earthquake of 1837, which had a great impact on the west coast - and expect more earthquakes that will also affect the west coast," said Dr. Lazar.
More of the topic in Hayadan:
The risk of strong earthquakes in the eastern Mediterranean is higher than previously estimated
Physicists from the Hebrew University formulated a new understanding of the friction process that causes earthquakes
Historical overview - the strongest earthquakes in our region so far
