More than 2,000 people were killed and thousands injured by a massive earthquake that hit southeastern Turkey, near the Syrian border, early Monday morning.
The earthquake, which struck near the town of Gaziantep, was closely followed by numerous wrecks – including one almost the size of the earthquake itself.
Why was it so deadly?
It was a big earthquake – registered as 7.8, classified as “big” on the official magnitude scale. It tore along about 100km (62 miles) of fault, causing serious damage to buildings near the fault.
Professor Joanna Faure Walker, head of the Institute for Risk and Disaster Reduction at University College London, said: “Of the deadliest earthquakes in any given year, only two in the last 10 years have been of similar magnitude, and four in the previous 10 years. years.”
But it’s not just the power of the quake that causes devastation.
This incident happened early in the morning, when people were inside and sleeping.
The sturdiness of the buildings is also a factor.
Dr Carmen Solana, reader in volcanology and risk communication at the University of Portsmouth, says: “The resilient infrastructure is unfortunately patchy in Southern Turkey and especially in Syria, so saving lives now depends largely on response. The Another 24 hours are crucial to find survivors. After 48 hours the number of survivors drops dramatically.”
This was a region that had not had a major earthquake for over 200 years or any warning signs, so the level of preparedness would have been less than for a region more used to dealing with tremors.
What caused the earthquake?
The Earth’s crust is made up of separate pieces, called plates, which nestle next to each other.
These plates often try to move but are prevented by friction against an adjoining plate. But sometimes the pressure builds up until one plate suddenly snaps across, causing the surface to move.
In this case it was the Arabian plate that was moving north and grinding against the Anatolian plate.
Friction from the plates was responsible for very damaging earthquakes in the past.
On 13 August 1822 it caused an earthquake that registered a magnitude of 7.4, much smaller than the magnitude of 7.8 recorded on Monday.
However, the 19th Century earthquake caused massive damage to the towns in the area, with 7,000 deaths recorded in the city of Aleppo alone. Aftershocks of damage continued for nearly a year.
Many aftershocks have already occurred after the current earthquake and scientists expect it to follow the same trend as the previous big one in the region.
How are earthquakes measured?
They are measured on a scale called the Moment Magnitude Scale (Mw). This replaced the better known Richter scale, which is now considered outdated and less accurate.
The number given to an earthquake is a combination of the distance the fault line moved and the force that moved it.
A tremor of 2.5 or less cannot normally be felt, but can be detected by instruments. Up to five tremors are felt and cause minor damage. The Turkey earthquake at 7.8 is classified as a major earthquake and usually causes serious damage, as in this case.
Anything above 8 does devastating damage and can completely destroy the communities in its midst.
How does this compare to other major earthquakes?
The earthquake off the coast of Japan in 2011 was registered as a magnitude 9 and caused widespread damage on the ground, and caused a series of huge tidal waves – one of which caused a major accident at a nuclear plant along the coast.
9.5 was recorded in Chile in 1960 the largest earthquake ever.