The Hellenic DataBase of Active Faults (HeDBAF): a new, national geodatabase of active faults for the broader Greek territory

A new geospatial database started to realize since 2021 including parametric and descriptive information about the active faults in the broader Aegean region (Eastern Mediterranean). The Hellenic DataBase of Active Faults (HeDBAF) is a national ongoing product developed under the auspices of the EPPO (Earthquake Planning & Protection Organisation) and the supervision of its Seismotectonics Committee. The responsibility of implementation, management and hosting is held by the Hellenic Survey of Geology & Mineral Exploration (HSGME).

Active fault databases for broader Greece already existed since about 2010. Besides the fact that these databases were materialized by small groups of researchers, their objectives were also rather narrow, offering data and information for particular purposes. The HeDBAF adopts conceptual approaches and characteristics from other time-proven national databases of the world (e.g. INGV’s DISS, IGME’s QAFI, etc.). It is a multi-layered tool that hosts all available literature data (e.g. scientific articles, technical/project reports, thematic maps, etc.), targeting various groups of end-users: the primary target group is the scientific community which often needs medium- to small-scale information for geodynamic interpretations, large-scale data for local seismotectonic analyses, and appropriate parametric information for numerical modelling. The next target group is the engineers who need large-scale detailed surveying of the fault traces and ground ruptures, and fault models for the prediction of ground motion in the context of Seismic Hazard Assessment. Administration, government, security bodies and local authorities can benefit from this geodatabase as a decision-making tool for safety and rescue planning. Last, but not least, a broad range of citizens will be able to access principal theoretical and parametric information about active faults in areas they are interested in.

Until today, two main fault datasets have started to develop: i) the Fault Traces, and ii) the Fault Zones datasets. The former focuses on the mapping accuracy of faults, targeting on large- to medium-scale data (> 1:50,000). Faults originating from smaller scale maps are reassessed (if possible) using hi-resolution topographic data. Primary co-seismic ground ruptures are distinguished from geologically detected fault traces to better understand the surficial rupturing process for fault rupture hazard purposes. The Fault Zones dataset involves fault segmentation and earthquake rupture scenarios which are crucial for Seismic Hazard Assessment (SHA). Thus, the fault zones are represented by medium- to small-scale lineaments which also facilitate the visualization of large tectonic structures in small-scale maps. The HeDBAF, as a very young effort still misses both fault occurrences and associated information. However, the geodatabase is continuously updateable and upgradeable showing frequent improvements and enrichments.