There have been fears of another major earthquake in Istanbul since the February 6 disaster that hit Turkey and Syria, but a leading Turkish seismologist has reassured the risk “has not increased”.
“The risk has not increased because we are talking about completely different systems,” Dogan Kalafat, director of the Earthquake-Tsunami Monitoring Center of the Kandilli Observatory in Istanbul, told AFP.
Turkey’s most populous city is located near the North Anatolian Fault and the recent magnitude 7.8 earthquake that killed 43,500 people occurred along another fault in the southeast of the country, Kalafat explained.
Still, the 16 million residents of Istanbul, a city that spans two continents and has seen a mushrooming of skyscrapers in recent years, are wondering if they are ready for the “Big One”.
“I would like to say it, but unfortunately, it is a very big city with too many poorly constructed buildings,” said Kalafat, who announced the use of low-quality cement and construction on “soft soils”.
As we await a large-scale earthquake, “we must make good use of the time. We must build earthquake-proof houses on solid soil. It is the most important precaution to be taken,” added the seismologist. emphasis.
At the observatory, seismologists take turns every eight hours looking at a series of computer screens monitoring possible tremors.
In front of them, on a wall at least five meters (16 feet) high, a huge screen provides real-time readings from 260 seismic stations across the country.
“Nine thousand have happened in Turkey since February 6,” which is more than “seven or eight times normal”, said Kalafat.
On one of the desks, a laminated map shows the North Anatolian Fault, which crosses the Sea of Marmara, only “15 to 17 kilometers” from Istanbul’s southern shore, Kalafat said.
In 2001, two years after a 7.4-magnitude earthquake killed 17,000 people in northwestern Turkey, Kalafat calculated a 65 percent probability of a magnitude-7 earthquake before 2030 in the same region—including Istanbul.
The risk increased to 75 percent in 50 years and 95 percent in 90 years.
“These statistics are still relevant,” said Kalafat, adding: “even with today’s technology, it is impossible to predict an earthquake.”
“We can indicate, with a certain margin of error, where an earthquake can occur and how big it can be, but we don’t know when it will happen,” he said.
The Kandilli Observatory has developed an early warning system “but Istanbul is too close to the fault line” for an effective system, Kalafat said.
On one of the desks, sitting between two screens, is a black telephone with two red labels with the acronym of the public disaster management agency, which allows scientists to send an alert of a major earthquake.
The early warning might have lasted “seven or eight seconds at most”—not enough time to let residents say goodbye.
In comparison, the telephone warning system in the Tohoku region of Japan, hit by a devastating earthquake and tsunami in March 2011, buys the public 45 seconds.
“Then, you can send a message warning citizens, but we don’t have this opportunity here,” he said.
© 2023 AFP
Quote: Quake-prone Istanbul not heightened risk: expert (2023, 25 February) retrieved 25 February 2023 from https://phys.org/news/2023-02-quake-prone-istanbul-heightened-expert.html
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