APPLICATION OF ENGINEERING GEOLOGICAL INVESTIGATIONS FOR SUSTAINABLE DEVELOPMENT THROUGH THE REDUCTION OF GEOHAZARD RISKS IN THE REPUBLIC OF CROATIA (GEO-RIZ)

APPLICATION OF ENGINEERING GEOLOGICAL INVESTIGATIONS FOR SUSTAINABLE DEVELOPMENT THROUGH THE REDUCTION OF GEOHAZARD RISKS IN THE REPUBLIC OF CROATIA (GEO-RIZ)

Funding source: NextGenerationEU

Duration: 1.10.2025. - 30.09.2029.

Project leader: Assist. Prof. Sanja Bernat Gazibara, PhD

Budget: 66.856,88 EUR

The main objective of the project is to improve engineering-geological knowledge and methods in order to reduce the risk of landslides, rockfalls, sinkholes and liquefaction, and to contribute to sustainable spatial development in the Republic of Croatia through the application of innovative technologies and modern research methods, the development of methodologies for the assessment of susceptibility to different geohazards, and the improvement of the reliability of the existing landslide monitoring and early-warning system.

The specific objectives of the project are:

1. To carry out continuous monitoring and continue the development of the existing early-warning system at the Kostanjek landslide (City of Zagreb).
2. To improve the Kostanjek landslide movement model through the application of remote sensing methods and the results of hydrological and hydrogeological analyses.
3. To update the Landslide Susceptibility Map of the Republic of Croatia at the scale of 1:100,000 using LiDAR technology.
4. To prepare landslide susceptibility maps for Krapina-Zagorje County and Sisak-Moslavina County at the scale of 1:25,000 using LiDAR technology.
5. To develop a zoning method for the purpose of interpreting landslide susceptibility models and their application in the spatial planning system of the Republic of Croatia.
6. To apply remote sensing methods for structural-geological analyses and spatial analysis of discontinuities for the purpose of assessing rockfall susceptibility at a detailed scale in intensely folded and faulted rock masses.
7. To develop a methodology for sinkhole susceptibility assessment at a large scale using LiDAR technology.
8. To develop a methodology for liquefaction susceptibility assessment at a large scale using LiDAR technology.

Work Packages

WP1 Kostanjek Landslide

The Kostanjek Landslide Monitoring Observatory was established in the period 2009–2014 within the bilateral Japanese–Croatian scientific research project “Risk Identification and Land-Use Planning for Disaster Mitigation of Landslides and Floods in Croatia.” Since its establishment, data on the movement of the largest landslide in the Republic of Croatia and on the causes of its movement have been continuously collected at the observatory. The Kostanjek Landslide Monitoring Observatory became an integral laboratory of the Faculty of Mining, Geology and Petroleum Engineering, University of Zagreb, in 2018. Research activities at the Kostanjek landslide within the present project include the further development and improvement of the early-warning system. The existing early-warning system was established within the applied research project PRI-MJER (KK.05.1.1.02.0020), when the application “Landslide Early Warning System (LEWS)” was developed. Within LEWS, threshold values of certain parameters (movement, rainfall, groundwater level, evapotranspiration) for different hazard levels were defined based on heuristic and statistical analyses of monitoring data.

The next phase of the project is focused on the updating and improvement of the physical model of the Kostanjek landslide in order to achieve a better understanding of the actual geological, engineering-geological and hydrogeological conditions and to improve the early-warning system. Special emphasis is placed on hydrogeological processes, since rainfall and groundwater level are key drivers of landslide activity, and their nonlinear relationship with movement velocity, as well as the influence of pore pressures and seepage forces, need to be clarified. The model will be improved through an interdisciplinary approach including geological, engineering-geological, hydrogeological, hydrological and isotope investigations. Geological investigations will include mapping and reinterpretation of the geological setting, while the engineering-geological analysis will integrate existing and new data, including high-resolution LiDAR imagery. Hydrogeological investigations will focus on groundwater levels and flow and on defining critical conditions for landslide reactivation. In addition, the origin of groundwater will be analysed using stable isotopes of hydrogen and oxygen, enabling differentiation between local infiltration and deeper inflows. Hydrological investigations of rainfall will include the analysis of intensity, duration and return periods, taking into account seasonal effects of evapotranspiration. All results are expected to provide a more reliable landslide model and a more effective early-warning system.

WP2 Geohazard maps

Geohazards imply hazards caused by geological processes, and in Croatia active geohazard processes include slope movements (sliding, flowing, rockfall, toppling and lateral spreading), subsidence and sinkhole collapse, erosion (gully erosion, coastal erosion), seismically induced hazards (earthquakes, liquefaction) and floods (flash floods and overflow of permanent watercourses). Within this project, landslides (sliding and flowing), rockfalls, sinkholes and liquefaction will be analysed, and maps will be prepared for these geohazards showing both the spatial distribution of the phenomena and the spatial probability of their future occurrence.

Part of the input data for the preparation of geohazard maps will be derived using a digital terrain model obtained from a point cloud produced by airborne laser scanning in 2021/2022 within the project “Multisensor Airborne Survey of the Republic of Croatia for Disaster Risk Reduction Assessment” (KK.05.2.1.10.0001). Since the available geological data are at the scale of 1:100,000 and the maps to be produced will be at medium to large scale, additional desk-based (remote) investigations and updates of input geological data will be carried out using the LiDAR DTM, as well as field investigations in order to verify the remote interpretation of lithological units and structural elements.

The produced geohazard maps will represent valuable spatial data that can be further applied in sustainable spatial planning and urban development, risk management and civil protection, environmental protection and natural resource management, defining climate change adaptation measures, as well as in further scientific and professional research, but also in education and workshops for students, professionals and the wider interested public. The preparation of geohazard maps plays a key role in risk reduction, spatial protection and population safety. The application of LiDAR technology and machine learning methods significantly increases the quality and efficiency of this process, thereby contributing to the modernization and improvement of spatial management because it enables: (i) high resolution and data accuracy; (ii) automation and rapid analysis of large volumes of spatial data; (iii) reduction of subjectivity; (iv) improved model predictability; (v) scalability and repeatability, i.e. application of the model in similar geological environments.

WP3 Diseminacija

Dissemination of project results includes the publication of scientific papers and presentation at international scientific conferences, organization of a workshop for the professional community and decision-makers, development of a project website on which the produced geohazard maps will be published through a WEB GIS interface, and the popularization of the scientific and societal contributions of the project.

Team members

Members from faculty:
	Assist. Prof. Sanja Bernat Gazibara, PhD – Project leader University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Croatia Homepage		Assoc. Prof. Martin Krkač, PhD University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Croatia Homepage
	Full prof. Snježana Mihalić Arbanas, PhD University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Croatia Homepage		Full prof. Bruno Tomljenović, PhD University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Croatia Homepage
	Full prof. Kristijan Posavec, PhD University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Croatia Homepage		Assoc. Prof. Krešimir Pavlić, PhD University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Croatia Homepage
	Assoc. Prof. Zoran Kovač, PhD University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Croatia Homepage		Marko Sinčić, PhD University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Croatia Homepage
	Hrvoje Lukačić, mag. ing. geol., mag. ing. min.   Sveučilište u Zagrebu, Rudarsko-geološko-naftni fakultet, Hrvatska Osobna stranica
External collaborators:
	Assist. Prof. Petra Jagodnik, PhD – external expert University of Rijeka, Faculty of Civil Engineering, Croatia Homepage		Mauro Rossi, PhD – external expert Istituto di Ricerca per la Protezione Idrogeologica (IRPI) of the Italian National Research Council (CNR), Italija Homepage

Dissemination

Conferences

Published papers

Master and bachalor theses