Connections between Thermal Springs and Deep Geothermal Potential in the Buda Thermal Karst System

The Buda Thermal Karst is characterised by three geographically and geologically separated discharge areas along the Danube in the Buda Hills (Erőss et al, 2012 etc.). These contain lukewarm, lukewarm - warm and warm springs, respectively. This research aims to find an answer to the question of the separation and differences of these discharge areas and their significance in geothermal exploration under the confined Pest side.

Along with the datasets used in previous numerical simulations (Szijártó et al, 2021 etc.), the Supervisory Authority for Regulatory Affairs Hungary (SARA) has made available a new three-dimensional geological model of the study area. This updated model enables more accurate numerical simulations.

In the numerical simulations of the recent study, we use the previous datasets and we are creating five two-dimensional cross-sections by Comsol Multiphysics. The evaluation includes a flow system and temperature analysis that relies on a comparison between model results and on-site measurement data. The primary objectives of the modelling include:

(1) evaluating the connection between lukewarm and warm springs of the Central system and the thermal waters in the deep confined karst areas of Pest

(2) assessing the structural separation of this system from adjacent Northern and Southern areas and its implications for geothermal exploration risks.

This research is directly linked to geothermal risk assessment by testing how numerical model outputs can be integrated into the development of general methodologies for geological risk analysis.

Preliminary findings suggest that the thermal springs of the Buda Thermal Karst Central system are connected to the regional discharge area at the Danube River. This indicates that the most favourable conditions for geothermal utilization can be found in areas near the Danube on the Pest side. However, these areas are also critical for protecting the water of the thermal baths, emphasizing the need to incorporate risk assessment into geothermal planning. The modelling results offer multiple applications concerning data integration. In this research, the theoretical temperature distribution estimated through statistical analysis of the model outputs can be used to predict the performance of geothermal projects and evaluate the geological feasibility of potential developments. This integrated approach highlights the importance of balancing geothermal energy utilization with conserving natural thermal resources.

This research was carried out within the framework of the project RRF-2.3.1-21-2022-00014 of the Climate Change Multidisciplinary National Laboratory.

Supported by the EKÖP-24 University Excellence Scholarship Program of the Ministry for Culture and Innovation from the Source of the National Research, Development and Innovation Fund. Contract number: ELTE/15380/1(2024)

References

Erőss, A., Mádl-Szőnyi, J., Surbeck, H., Horváth, Á., Goldscheider, N., & Csoma, A. É. (2012). Radionuclides as natural tracers for the characterization of fluids in regional discharge areas, Buda Thermal Karst, Hungary. Journal of Hydrology, 426, 124-137.

Szijártó, M., Galsa, A., Tóth, Á., & Mádl-Szőnyi, J. (2021). Numerical analysis of the potential for mixed thermal convection in the Buda Thermal Karst, Hungary. Journal of Hydrology: Regional Studies, 34, 100783, pp.2.