Prof. Dr. Marmara earthquake warning from Osman Bektaş: Shake duration and frequency are critical in Istanbul

Geological Engineer Prof., who frequently comes to the fore with his social media posts. Dr. Osman Bektaş made a new assessment of the earthquake danger in the Marmara Region.

Bektaş stated that the impact of an earthquake that may occur in Marmara cannot be measured only by magnitude, and that the frequency and duration of the earthquake are critical for Istanbul.

Osman Bektaş pointed out that especially long-term ground movements can have a greater impact on tall and flexible buildings.

Drawing particular attention to the 6.2 magnitude Silivri earthquake, Bektaş stated that the slower and segmented rupture of the fault, as well as the thick and young sediment cover of Marmara, could affect the characteristics of the ground motion.

In his post, Bektaş pointed out that an earthquake of the same magnitude may not be felt in the same way in different regions and used the following expressions:

"ISTANBUL DOES NOT HAVE TO SHAKE LIKE IZMIT!

An earthquake of the same magnitude;

It may cause a short and sharp shaking in Izmit, and a slower and longer shaking in Istanbul.

Why?

Slower rupture of the Main Marmara Fault

Marmara's high heat flow and fluid weak fault zones

Thick, young marine and coastal sediments can highlight long-period earthquake waves.

Result:

Tall and flexible buildings may be subject to larger emissions.

Low and rigid buildings may be less sensitive to this long-term movement.

"Just as each ground behaves differently to earthquakes, each region responds to different frequencies of earthquake waves according to its geological characteristics."