Landslide hazard analyses in Armenia require consideration of the seismotectonic context of the Lesser Caucasus. As it is located near the center of the Arab-Eurasian collision, the Lesser Caucasus is characterized by its complex geology, dense fault network and mountainous relief; it is marked by recent volcanic and seismic activity largely influencing slope stability at different scales. We therefore sought to identify all major landslides in the Armenian Lesser Caucasus and to understand the environmental factors contributing to regional landslide susceptibility. We performed spatial and size-frequency analyses using two landslide catalogues as inputs: “Georisk”, provided by the Georisk Scientific Research Company, and “Matossian”, herein. Our spatial analyses show that landslide susceptibility depends on many factors according to the area considered: near faults, a tectonic influence on slope stability is clearly observable, whereas high concentrations of landslides in northern mountain regions, marked by a wetter climate and far from known active faults, show that climatic factors also strongly contribute to slope-failure potential. The influence of volcanoes and volcanic deposits on the development of mass movements is unclear and requires further analysis. The aforementioned inventories do not include any records of volcanic flank collapses, although we expect at least one case in the eastern Lesser Caucasus.

The territory of the Republic of Armenia (RA) lies within the central Arabia–Eurasia collision zone and is characterized by rugged mountain landscapes, complex geology, active faulting, and seismicity. Armenia is highly vulnerable to seismic and landslide hazards, with more than 2504 active landslides mapped in the country. A significant landslide in the Tumanyan Community, Lori Marz, was activated in January 2018 and threatened critical infrastructure, including the railway linking Armenia to Georgia and the M6 interstate highway. The landslide’s activation was driven by groundwater, a nearby water reservoir leak, and adjacent infrastructure. Preliminary hazard analysis revealed that further movement of the landslide could dam the Debed River, leading to potentially catastrophic downstream impacts. In response, the Minister of Emergency Situations of RA requested urgent studies by the Institute of Geological Sciences of NAS RA. Surveys began on 22 January 2018, involving an interdisciplinary approach including geotechnical study, UAV-based digital mapping, and application of geophysical methods, such as MASW, microtremor recordings, GPR, and VES. The combination of these methods provided reliable information on the landslide’s geotechnical structure, identified the sliding plane, and allowed for numerical slope stability modeling, which confirmed the landslide’s unstable condition and susceptibility to reactivation from earthquakes or elevated groundwater. Based on this complex research, protective measures were developed and applied, including, in particular, horizontal drilling to dewater the sliding plane. These emergency measures stabilized the landslide, mitigating immediate threats to infrastructure and ensuring relative safety.

A destructive earthquake, especially if it occurs in areas of high seismic risk, in the form of certain factors, has a significant impact on the environment, including biodiversity. These factors (earthquake effects) are determined by the strength of the earthquake (manifestations of intensity on the earth’s surface), local conditions (geomorphological, geological structure, level of urbanization and seismic risk, etc.), disaster-zone recovery processes (fast and effective recovery, localization and prevention of secondary consequences, environmental protection, state opportunities and political decisions, etc.). It is clear that these three important basic conditions of effects are different in different seismic regions and countries, which means that the impact of an earthquake on the environment is different. To consider the features and factors of the impact of an earthquake on the environment, the 1988 Spitak earthquake—one of the most detailed and comprehensively studied earthquakes in the world—was taken as a test object. The main purpose of this article is to highlight in more detail and more fully the possible natural and human factors of the impact of a strong earthquake on the environment and predict the extent of these impacts. Thirty-six major earthquake factors affecting the environment have been identified, which are conditionally divided into three main groups according to the time of formation and genesis: (a) purely seismic, (b) secondary seismic, and (c) post seismic. The paper also attempts to assess possible changes in these factors depending on global warming and a decrease in precipitation.