6 February 2023
Potential landslides from the 6 February 2023 Mw=7.8 earthquake near Nurdağı in Gaziantep, Turkey
Initial reports from the area affected by the Mw=7.8 earthquake near Nurdağı in Gaziantep, Turkey in the early hours of 6 February 2023 indicate that this will be a very serious event. Some parts of the media are chasing the reported number of fatalities in Turkey and Syria, whereas it is likely that the number of deaths will be in the high hundreds at least, and probably in the thousands. In the aftermath of the Haiti earthquake in 2010 I wrote about disaster reporting – these points will apply here.
Landslides are likely to have been a significant problem in this event. The best available information comes from the USGS ground failure model, although this is very provisional at this stage. The earthquake itself had a strike slip mechanism, with the fault orientated NE-SW. The provisional USGS landslide probability map looks like this:-
It is important to emphasise that this is provisional. The map will improve as better data becomes available about the fault and the mechanisms of the earthquake. But the above model has allowed the USGS to make an initial estimation of the area affected by landslides and of the population that has been exposed to the hazard:-
Based upon this we are likely to see some landslide fatalities plus substantial numbers of roads blocked by failures. This will impede the rescue work, especially in the initial, all-important, 24 hour period, in more remote areas. In general, landslides from strike-slip earthquakes cluster close to the surface expression of the fault trace, although some can still occur at considerable distances.
At the time of writing there are few images from the area affected by the earthquake, mostly showing collapsed buildings. However, Daily Sabah has an interesting image showing Gaziantep Castle, which appears to have at least partially collapsed:-
Note the retaining wall failure at the foot of the slope.