Landslide hazards in the area affected by the 2023 °Õü°ù°ì¾±²â±ð-Syria earthquake
It is well-established that landslides are a major threat during earthquakes in mountain areas. In the last few decades, it has become increasingly clear that the first very major rainfall event after the earthquake poses a further period of landslide significant hazard. The level of threat remains heightened during subsequent years, although the period over which this lasts is poorly understood. It is likely to be associated with the specific conditions geological, topographical and climatic conditions in the area affected. This remains an area of active research.
A really interesting, open access, paper with an all-star cast of authors () has examined this effect in detail in relation to the 6 February 2023 °Õü°ù°ì¾±²â±ð-Syria earthquake. I wrote about , and the , in some detail at the time, and . However, highlight that a part of the area affected by the earthquake was struck by a major "atmospheric river" rainfall event just 36 days after the main shock.
The scale of the earthquake itself has quickly faded from the communal memory beyond Turkey and Syria, sadly. report that 59,000 people were killed and over 107,000 were injured - a disaster on an epic scale. The atmospheric river that followed on 15 March 2023 impacted the eastern part of the earthquake zone, centred on Tut (Adiyaman), with a peak precipitation of 183 mm in 20 hours. The authors report a further 12 fatalities from this rainfall event; at least four of these resulted from a debris flow that struck a house. The impacts of the rainfall were intensified by the presence of lying snow, which rapidly thawed to increase the availability of moisture.
suggest that the threat of landslides after an earthquake in this area will depend on the timing of the mainshock, as atmospheric river events are strongly seasonal in the area affected by the 2023 °Õü°ù°ì¾±²â±ð-Syria earthquake. The timing of the earthquake, just before an atmospheric river event, was deeply unfortunate. This has major implications for other places - for example, I shudder to imagine the impact of the overdue major earthquake in Nepal should it occur in the peak SW (summer) Monsoon season. Or imagine a major earthquake coinciding with a landfalling typhoon in the Philippines.