Türkiye’s twin quakes not a common phenomenon: geophysicist

Part of what is remarkable about Monday's earthquake 7.7 magnitude earthquake is that it triggered the second 7.6-magnitude earthquake, which is not a common occurrence, Saskia Goes, professor of Geophysics at Imperial College in London, has said. 

In an interview with TRT World, Goes explained that earthquakes normally trigger many aftershocks of smaller magnitude, however, Monday's quake triggered another of almost the same size. 

The powerful earthquakes which hit southeastern Türkiye this week were three times stronger than the 1999 Marmara earthquake in the country's northwest, President Recep Tayyip Erdogan said on Saturday during his visit to the southeastern Diyarbakir province.

According to Goes, the high level of destruction occurred because the quake was relatively shallow.

"That's a property of these types of faults - that the earthquakes happen pretty shallow and the shaking dies away quickly from the source. So the closer you are to the source, the more intense the shaking is," she explains. 

The first 7.7 magnitude quake occurred along the eastern Anatolian fault - a well-known fault zone in eastern Türkiye.

The country's Disaster and Emergency Management Authority (AFAD) official Orhan Tatar said on Saturday that the 7.7 magnitude earthquake made an effect of and released energy as powerful as 500 atomic bombs.

'Equal to 500 atomic bombs'

Goes says that Türkiye's 1939 earthquake, which struck the eastern Erzincan Province, made future earthquakes more likely.

"It triggered a whole sequence of larger earthquakes between 1939 and 1999, migrating westward along the fault zone," Goes tells TRT World. 

However, the changes in stress caused by one earthquake are relatively small compared to the total stress needed to make a fault break, Goes went on to explain. It is therefore difficult for scientists to know if a particular quake will increase the frequency of quakes in a country or region. 

AFAD official Orhan Tatar said that the duration of the first earthquake with a magnitude of 7.7 was 65 seconds, and the duration of the second earthquake was 45 seconds.

With two earthquakes, the region was seriously shaken for about 2 minutes.

On the volcanic activity in the area, Tatar said "there is no lava flow, volcanic ash, oil, or gas emission in the region."

"According to our observations, the incident in Kahramanmaras is nothing more than a simple mass movement that is triggered by the earthquake and that we see very often after tremors." he added.

The magnitude 7.7 and 7.6 earthquakes affected more than 13 million people across 10 provinces in Türkiye, including Hatay, Gaziantep, Adana, Adiyaman, Diyarbakir, Kilis, Malatya, Osmaniye, and Sanliurfa.

According to the UN, more than 5 million people may now be left homeless in northern Syria, which is already suffering from a 12-year civil war and a refugee crisis. 

"Currently, 160,000 personnel are working in 10 provinces, together with the teams from abroad," said Erdogan, who also met with quake victims in Diyarbakir.