After the devastating earthquakes in Türkiye and tremors recorded in neighboring Georgia, landslides increased in the eastern Black Sea region, with experts from two universities in the area recently relating them closely to the quakes and explaining how they occur.
The geologists have noted three landslides after the Kahramanmaraş earthquake and 12 after the Georgia earthquakes, especially in Artvin, where tremors were felt during the earthquakes in the neighboring country.
"The secondary feature of the earthquake is that it triggers landslides and rocks fall. This is an alarm or a warning," professor Osman Bektaş noted, although clarifying that the north-facing slopes of the eastern Black Sea coast are "extremely faulted, fractured and landslides are widespread."
Following the strong twin earthquakes of Feb. 6 that affected vast swaths of the country’s southeastern region, another three earthquakes measuring 4.0, 4.2 and 4.4 on the Ritcher scale were recorded in western Georgia on Feb. 11 and 12. Additional 6.4 and 5.8 earthquakes rocked Türkiye’s already devastated southern province of Hatay on Feb. 20 within intervals of only three minutes, thus causing the land to shift and an eventual increase in the frequency of landslides in the eastern Black Sea region.
Especially in Artvin, a city in the northeast, close to the Georgian border, 15 landslides have occurred at different points, likely related to the effect of the precipitation after the earthquakes. Three of the landslides, however, reportedly occurred right after the Kahramanmaraş-centered earthquakes.
Experts, including Karadeniz Technical University (KTU) former faculty member and geological engineer Osman Bektaş and associated professor Veli Süme from Rize’s Rize Recep Tayyip Erdogan University (RTEU) Faculty of Civil and Engineering, emphasized that it is necessary to be cautious about landslides.
Stating that natural events such as earthquakes and landslides are related, experts pointed out that soil and debris can be knocked loose by rain and wind.
Earthquake influence
Stating that the geography of Artvin has been affected by four earthquakes over the past three weeks, Bektaş explained that the tremors in Georgia, belonging to the Caucasian thrust belt, occurred just north of Artvin.
"Therefore, the region has been affected by earthquakes from both the north and the south for the last 15-20 days," he said.
"The frequency of rockslides may depend on this, but further research is needed. For example, if the number of rockslides and landslides before the earthquake is compared with the number after the earthquake, the effects of the quakes, seismic movements from the north and south, on faults and landslides can be revealed," Bektaş highlighted.
Alarm and warning
Regarding landslide slippage in relation to the seasonal conditions and earthquake tremors, Bektaş said: "Earthquakes may trigger mass movements in the region or increase with precipitation, and may occur more easily."
"Our highways, which pass from north to south in the eastern Black Sea mountains, were already threatened by rockslides and landslides on very steep slopes at the summits of the mountains. The highways should take precautions in the areas where the landslides occurred. We need to act a little more carefully," he noted. Pointing out that the safety of the roads must be ensured, he also said that the frequent occurrence of landslides is an alarm or warning and that more meticulous work should be done before the rainy season or future tremors.
"Occasionally, large boulders fall on the road, or people’s lives are threatened. We need to be more careful on the steep roads and in places where the population is dense," Bektaş said.
Associate professor Veli Süme also stated that there is concern among the people after the earthquakes because the land in the region is rugged. "We know that the topographic structure of Rize, with its uneven terrain, contains soil layers that loosen with precipitation or by earthquakes, triggering landslides.
"There are many citizens who want it to be investigated. This shows that Rize was also affected by the earthquakes. We need to take more precautions," he said.
On Thursday, a landslide also occurred in the Doğanşehir district of Malatya, one of the provinces where the Feb. 6 earthquakes were felt most severely. After the incident, District Mayor Durali Zelyurt, who went to the Karanlikdere neighborhood where the event occurred, stated that a street consisting of 15 households in the district disappeared with two devastating earthquakes in Kahramanmaraş and the landslide that followed. The mayor, however, noted that no one was killed in the incident.