← Back to Sessions

Landslides Triggered by the February 6, 2023 Kahramanmaraş Earthquake Sequence

Description: 

The devastating Kahramanmaraş earthquake sequence occurred on February 6, 2023. Two main events, estimated as Mw 7.7 and Mw 7.6 by the Kandilli Observatory and Research Institute, occurred nine hours apart and affected 10 cities and subjected an area >100,000 km2 to shaking levels known to trigger landslides (PGA >8% g). About 15% of this area has slopes greater than 20°. Initial estimates of globally available predictive landslide models indicated an extensive spatial distribution of hazard and population exposure, and many road blockages. In the days immediately following the earthquake, we examined high-resolution satellite images and aerial photos and used other remote sensing techniques (e.g., InSAR, change detection) to search for landslides of particular concern for human safety and to provide situational awareness to authorities. We also sought to gain better insight into the co-seismic landslides and their possible post-seismic consequences. This remote campaign was supplemented a few weeks after the earthquake by field surveys. Here we present the preliminary findings of these investigations.

Our observations showed that the earthquake sequence resulted in numerous co-seismic landslides, especially in the north. Surface rupture through mountainous terrain caused some large and sometimes fatal landslides. Rock falls were the most widely observed co-seismic landslide type though we also noted bedrock rotational, planar slides, lateral spreading, and rock avalanches. Lithology, spatial variability of ground shaking, topographic relief, and the arid/semi-arid climatic conditions appear to be the main variables controlling the spatial distribution of the observed co-seismic landslides. Intense ground shaking strongly deformed and damaged many hillslopes and mobilized some deep-seated landslides, so in the post-seismic period, we expect that heavy rain and snowmelt may result in a considerable number of additional failures and deformation on those hillslopes. Therefore, long-term monitoring may be needed to understand the earthquake legacy effect and post-seismic hillslope response.

Session: February 2023 Mw 7.8 Earthquake Sequence in Turkey

Type: Oral

Date: 4/19/2023

Presentation Time: 04:30 PM (local time)

Presenting Author: Kate Allstadt

Student Presenter: No

Invited Presentation: 

Authors