A specialist scientist scientifically explains the devastating Turkey-Syria earthquake!
A very strong earthquake has hit southeast Turkey near the border with Syria, and sensors around the world are picking up the seismic waves.
The tremors caused by the movement of energy from a source or epicenter have already had serious consequences for people living nearby.
Numerous buildings collapsed, two countries (Turkey and Syria) are thought to have killed at least 2,000 people, and there are reports of damage to gas pipelines that led to fires.
Why did it happen here?
This region of Turkey is prone to earthquakes because it is located at the intersection of three tectonic plates that make up the earth’s crust: the Anatolian, Arabian and African plates. The Arabian Plate is moving north towards Europe, causing the Anatolian Plate (on which Turkey is located) to be moving west.
The movement of tectonic plates increases pressure on fault zones at the boundaries between them. It is the sudden release of this pressure that causes earthquakes and earth tremors.
This last quake probably occurred on one of the main faults demarcating the boundary between the Anatolian and Arabian plates, either the East Anatolian fault or the Dead Sea deflection fault. Both are “slip faults”, which means they accommodate some of the movement of the plates as they shift relative to each other.
“much larger” than previous earthquakes
While there are many earthquakes in this region every year due to the constant movement of tectonic plates, Monday’s quake is especially strong and destructive as a lot of energy was released.
The USGS says that only three earthquakes greater than magnitude 6 have occurred within as little as 250 km (155 miles) of the site since 1970.
The February 6 event, with a magnitude of 7.8, is much larger than those that have occurred in the region before, releasing more than twice as much energy as the largest earthquake previously recorded in the region (magnitude 7.4).
Modern seismologists use a measure of magnitude, which is the amount of energy released by an earthquake (the old Richter scale, although it is sometimes misquoted in the news).
This scale is non-linear: each step up corresponds to a 32-fold increase in the energy released. This means that magnitude 7.8 actually releases about 6,000 times more energy than the more moderate earthquakes that typically occur in the area.
We tend to think that seismic energy comes from a single location or epicenter, but it is actually caused by movement along a fault zone. The stronger the earthquake, the more the fault area will move.
For something as large as 7.8 on the Richter scale, there would likely be movement over an area about 190 kilometers long and 25 kilometers wide. This means that the vibration will be felt by people over a very large area.
It is estimated that strong to violent tremors (enough to cause significant property damage) were felt by 610,000 people in the vicinity.
What about aftershocks?
After large earthquakes, there will be many smaller earthquakes, known as aftershocks, as the earth’s crust adjusts to voltage changes. They can last from a few days to several years after the initial event.
In the first 12 hours after the initial earthquake, southeastern Turkey has already experienced three more earthquakes of magnitude over 6.0. The first was a magnitude 6.7 that occurred just 11 minutes after the first shock, and there were hundreds of smaller aftershocks.
Later in the morning, another very large 7.5 magnitude event occurred to the north on another but adjacent fault system: the Syurgyu Fault.
Technically, this quake was strong enough to be considered a separate quake in its own right, although it likely triggered the first quake and generated its own series of aftershocks.
Although aftershocks are usually much weaker than the main shock, they can be just as devastating, causing additional damage to infrastructure damaged during the first earthquake and making rescue efforts more difficult.
As the effects of this massive earthquake continue to be felt by the people living in the area, we can only hope that international assistance reaches Turkey and Syria as soon as possible to help with the ongoing rescue effort amid the ongoing tremors.
The report was prepared by Jenny Jenkins, Assistant Professor of Geosciences, Durham University.
Source: Science Alert