In central Turkey, under the arid plains near Lake Tuz, a hidden geological shift is quietly unfolding. The Tuz Gölü Fault Zone, stretching nearly 200 kilometers, was once thought to be a lateral fault like many others in earthquake-prone Turkey. Recent research suggests a different story: this fault is expanding, not sliding.
A team of researchers, led by Axel Schmitt from Curtin University, analyzed ancient lava flows around the dormant Hasandağ volcano. They discovered that instead of sliding sideways, the crustal blocks are pulling apart, changing how we understand tectonic activities in this region.
Using a method called zircon double-dating, the team dated four lava flows between 151,000 and 38,800 years old. They found these flows were vertically fractured but remained aligned, indicating that the fault primarily creates vertical movement about 0.90 to 1.23 millimeters a year. This contradicts previous beliefs about lateral displacement, which had been thought to occur at rates up to 4.7 millimeters a year.
The previous models relied heavily on remote sensing and GPS data, which suggested significant horizontal movement. However, the new findings reveal a consistent vertical shift, especially notable in the F3 lava flow, further supporting the idea that the Tuz Gölü Fault is not a typical strike-slip fault but instead is undergoing a process of crustal extension.
Interestingly, the Tuz Gölü Fault has been relatively quiet when it comes to seismic activity. This doesn’t mean it’s inactive; rather, significant changes are happening beneath the surface. The researchers emphasize that while the North Anatolian Fault is known for its frequent quakes, the Tuz Gölü Fault is reshaping the landscape in its own way without drawing attention.
In fact, the way researchers date and reconstruct past geological events can shift our understanding of tectonics as a whole. Many active faults, especially in regions without much monitoring, might show similar ‘hidden’ behaviors. The study shows just how critical long-term data is for assessing seismic risks.
As climate change and urban expansion alter how we interact with the land, recognizing less obvious seismic hazards becomes crucial. The Alpine-Himalayan seismic belt, which includes Turkey, is more intricate than commonly perceived, suggesting that scientists need to integrate long-term geological data into their assessments of earthquake risks.
For more details, you can refer to the original research published in Nature Communications Earth & Environment.
