Landslide activation and monitoring are the focus of researches that are conducted as part of the RESPONSa project, intending to develop the structure of the landslide early warning system.
Taught by the experience from previous project (safEarth), during which a large landslide in Hrvatska Kostajnica in 2018 was activated and dozens of houses were destroyed, the RESPONSa project envisages some activities related to emergency field interventions. Although earthquakes are one of the landslide triggers, none of project team members at that time linked these activities to an earthquake.
On 29 December 2020, a destructive earthquake with a local magnitude of 6.2 with the epicenter near Petrinja (Croatia) caused the loss of seven lives and enormous damage to buildings and infrastructure in a wider area of Sisak-Moslavina County. The earthquake also initiated a variety of geological processes and phenomena (such as landslides and rockfalls; sand boils, subsidence, and lateral spreading as a consequence of liquefaction; dropout and suffosion dolines), that can represent a direct or indirect threat to the community and their property.
In cooperation with the Directorate of Civil Protection and representatives of the local communities, the RESPONSa team from the Croatian Geological Survey has on several occasions conducted geological inspections in the area of Petrinja, Hrastovica, Letovanić, Stari Brod, Stari Farkašić, and Sunja, where landslides and sand boils have been reported.
In those areas, the earthquake caused slope processes that are mainly related to the reactivation of existing (older) landslides and are mostly related to geological units which are known as susceptible to landslides. Besides, the special type of landslide, known as lateral spreading, is the result of liquefaction and is frequently related to flat sides along rivers causing river banks to fail.
After geological inspection, expert opinions were delivered to the local communities, emphasizing the necessity of landslide mitigation and landslide monitoring in the following periods with intense and/or prolonged rainfall events, when those landslides can be reactivated.
All the previously mentioned actions have strengthened the cooperation with the local communities and the Directorate of Civil Protection, and the experience gained will have, in the long term, a positive impact on the future project activities – assessing the capacity of the local community and developing operational processes for different geohazard scenarios.
Read more on project RESPONSa here.