Literal groundbreaking research by Dr. Giorgio Arriga enhances our understanding of the long-term evolution of seismogenic (earthquake-related) faults in the Apennines of Central Italy. Arriga’s study examines the development of fault systems over millions of years and their impact on present-day seismic hazards. His research included an investigation of faults in the L’Aquila Basin, a region severely affected by a major earthquake in 2009 that claimed over 300 lives, leading to a significant discovery.

The findings are published in the journal Tectonics.

“Our team analyzed the spatial interactions between different active fault segments in the L’Aquila Basin over time, particularly the Pettino and Paganica faults,” says Dr. Arriga. “Although these faults appear disconnected at the surface, seismic data suggested otherwise. Our field research and geochemical analyses provided evidence of a structural connection between these active faults.

“Using uranium-thorium-carbon dating, in collaboration with laboratories in Taiwan, we were able to establish geological constraints on the timing of this connection. Our discovery has significant implications for seismic hazard assessments, as connected faults can generate larger and more destructive earthquakes.”

Arriga’s research, conducted at the AMGC laboratory at Vrije Universiteit Brussel (VUB), focuses on bridging the gap between short-term seismic studies and large-scale tectonic processes. While conventional studies analyze fault activity over the past 40,000 years to assess an area’s current seismic risk, Arriga’s work significantly extends this timeline by reconstructing the geological history of fault networks over millions of years.

In collaboration with the Leibniz Institute for Applied Geophysics in Germany, Arriga’s team contributed to the development of an innovative thermochronological dating technique for tectonic environments in carbonate rocks. By applying thermoluminescence dating to newly formed dolomite minerals in fault structures, the team determined that tectonic activity in the region began approximately 2.7 million years ago.

Thermoluminescence (TL) dating is also used for very ancient archaeological finds. When buried rocks and minerals remain in darkness, they absorb cosmic radiation and radioactivity. Upon being heated or exposed to the surface, they release stored radiation in the form of light. The amount of light emitted provides a measure of how long the materials have been buried. This method fills a crucial gap in geochronological techniques and enables researchers to study the evolution of faults over extended timescales.

Additionally, stable and clumped isotope analysis was conducted at the AMGC laboratory to determine the depth at which fault-related mineral deposits formed. By analyzing these carbonate mineralizations, the researcher concluded that some fault structures originally formed at depths of 1.5 to 2 kilometers and have since been uplifted due to ongoing tectonic activity.

The implications of Arriga’s research are profound. By confirming that fault segments in Central Italy form interconnected systems capable of generating larger earthquakes, the study highlights the urgent need for detailed geological and seismic hazard assessments. “The research provides a geological framework that serves as a foundation for short-term seismic studies,” says Arriga.

“By understanding how faults have evolved, we can better predict their future activity and contribute to safer urban planning in Central Italy and beyond,” concludes Dr. Arriga. “With continued collaboration between international research institutions, we can pave the way for further advancements in earthquake science and risk mitigation strategies.”

The study was conducted as part of a joint Ph.D. program between Roma TRE University and the VUB.