The western Mediterranean basin is a dynamic region characterized by complex tectonic interactions driven by the northwest-southeast convergence of the African and Eurasian plates. This convergence generates significant seismicity, making the Mediterranean one of the most seismically active and hazard-prone regions globally. Historical earthquakes have caused substantial socioeconomic damage, with notable events including the 1755 Lisbon earthquake, the 1908 Messina earthquake, and multiple events in the Maghreb region, underscoring the region’s vulnerability to seismic hazards and related geohazards such as landslides and tsunamis.

In Algeria, the Tell Atlas belt represents a critical segment of this tectonic boundary, where the diffuse collision zone complicates seismic hazard assessment. The 1980 El Asnam earthquake (M 7.3) was a pivotal event, drawing global attention from scientists and risk practitioners to the region’s seismic risks. This devastating earthquake highlighted the need for improved seismic monitoring and hazard mitigation strategies.

Five years later, on October 27, 1985, a moderate earthquake (Ms 6.0) struck near Constantine, a major city in northeastern Algeria. Despite its moderate magnitude, this event was scientifically significant, revealing the complexity of the plate boundary. Unlike the thrust-dominated tectonics observed in earlier events, the Constantine earthquake occurred along a strike-slip fault, marking a new phase of research into the region’s seismotectonic framework.

Over the past four decades, significant advancements have been made in seismic monitoring, geodynamic understanding, seismotectonic analysis, and geohazard mitigation in Algeria. The establishment of the Algerian Digital Seismic Network (ADSN) in 2006 revolutionized seismic monitoring, enabling detailed studies of earthquake sequences. Notable events include the 2020 Mila earthquake (M 4.9), which triggered a massive landslide near the Beni Haroun Dam, highlighting the interplay between seismic activity and secondary geological hazards. In 2021, a M 6.0 earthquake offshore of Bejaia, along a thrust fault system, became the largest event in the region since 1985, further emphasizing the need for continued research and preparedness.

These events underscore the importance of interdisciplinary collaboration among scientists, risk mitigation practitioners, and urban planners. By commemorating the 1985 Constantine earthquake and sharing knowledge gained over the past decades, the scientific community aims to enhance seismic resilience and safeguard communities across the Mediterranean region.