In the Vrancea seismic region (Romanian Carpathians; the most important intermediate-depth seismic source of Europe), the morphology of the slopes is often marked by the existence of numerous high-magnitude, deep-seated active, dormant or relict landslides, which are the subjects of many cases of functional and structural connectivity. Due to the compact and extensive (coniferous and broad leaved) forest coverage and because of the lack of publicly available regional high-resolution DEMs, it is usually difficult to fully understand the morphogenetic framework of such large, deep-seated landslides in order to assess their frequency–magnitude relationship, a key issue in hazard quantification. However, the high impact of such landslides on river networks requires an in-depth understanding of the multi-hazard framework, as cascading effects are likely to affect the presently growing human activities developing along the valleys. Within a case study represented by a 2.5 km long deep-seated landslide, that caused a 500 m lateral occlusion of Buzău River, we used integrated remote sensing technologies (UAV laser scanning) and in situ (geomorphic mapping and ERT investigations) techniques, which allowed us to better understand the structural connectivity which conditions the landslide hazard in such complex morphogenetic conditions, outlining the present potential of the regional seismo-climatic context to trigger potential high-magnitude chain effects.

The evolution of discontinuous mountain permafrost presently preserved in high-altitude central and SE European mountain ranges can be regarded as an indicator of climate warming. Considering recent climate scenarios, these areas are prone to become the expression of the transition from inactive to relict landforms, with potential impact on hydrologic regimes and related hazards intensity. The last two decades document permafrost existence and ground thermal regime in rock glaciers and rockwalls in the highest massifs of the Carpathian and the Balkan mountains, with several studies also assessing ground temperature response to both warming and snow regime changes in periglacial areas from the Eastern Alps. The objective of this research is to evaluate multidecadal patterns of temperature and precipitation indices relevant for possible impacts on mountain periglacial landforms in Central and S-E European ranges. Available continuous climate data were used from meteorological stations situated above 2000 m altitude in: a) Tatra Mts (Chopok, 2007 m; Lomnicky Stit, 2635 m); b) Julian Alps (Sonnblick, 3111 m; Kredarica, 2515 m); c) the Southern Carpathians (Vf Omu, 2505 m) and d) Rila Mts (Musala, 2927 m). We check for similarities between trends at regional scale and validate inferred influences through in-situ data series focusing on snow cover variability retrieved from ground temperatures. Specifically, in-situ measurements of permafrost and freezing ground indicators from rock glaciers and rockwalls in the Southern Carpathians were used to give an estimate of permafrost condition and duration of seasonal frost in comparison to thermal and pluvial variations. Ground surface freezing index (Fi) during the cold snow-free interval was considered a particularly important index and was also assessed using data from the Southern Carpathians and Rila Mountains meteorological stations for comparison and validation. The preliminary results on climate variability analysis in the selected mountain ranges show that mean annual air temperature values are increasing in all locations with similar mean rates (approximately 0.032 °C/yr). Both warm and cold season thermal regimes contribute to this trend, with only slight inter-site differences. The variability of solid and liquid annual precipitations and the monthly multiannual analysis of data highlights distinct pluvial patterns correspondent to local topo-climatic characteristics of each mountain range. The rain/snow ratio expresses a direct impact on permafrost and frozen ground by the reduction of the snow cover period and increasing of the warm snow free interval, which enables exchanges between ground and warm atmosphere and potentially disturbs the thermal balance of ground-preserved ice. Specifically, the Fi values are shown to be recently reducing, which equals with a lowering ground cooling degree before the onset of the isolating snow cover. This is also reflected by other changing cold season characteristics, i.e. duration of snow-free and zero-curtain intervals, snow-cover thickness and seasonal frost duration. In such changing conditions, periglacial landforms in the mountain ranges from Central and S-E Europe would be exposed to inactivation which questions the medium to long-term preservation of permafrost.

In mountain regions, landslides are enhancing the short- to long-term slope denudation and sediment delivery, conditioning the general landscape evolution; meanwhile, their regional typological patterns should be properly incorporated into single- to multi-hazard evaluations for a proper mitigation of consequences and risk management strategies development.  The Carpathians are an elongate and twisted young mountainous chain of Europe, which is continuing the Alpine orogenetic system towards the internal, Central and Eastern parts of the continent, covering parts of Austria, Czech Republic, Slovakia, Poland, Ukraine, Romania and Serbia. Their heterogeneous morphological and litho-structural forming conditions, the regional climatic traits and the extremely complex and complicated political and socio-economical development stages resulted in a landslide-prone environment, as outlined through numerous scientific works. Nevertheless, there is little synthesis information which can allow a clear evaluation of the entire mountain chain, highlighting the importance of such a study in the present-day context of climate variability and change analysis. As part of the broad landslide typological spectrum, the deep-seated landslides are important paleo-environmental witnesses which may offer substantial information within the risk management and resilience construction context under the modern challenges of climate change impact evaluation. The complexity (many times site-specific) of deep-seated landslides susceptibility and hazard evaluation is enhanced by the (very) high magnitude of such processes, marking with a substantial share the evolution of the coupled slope and channel morphodynamic systems, an interface usually prone to the development of human activities, thus driving the fundamental understanding of their morphogenesis towards highly applied exposure analysis, vulnerability evaluations and risk mitigation concerns. In order to obtain a full extent evaluation of the implication of deep-seated landslides in hazard assessment, a consistent literature review was performed. Several key-issues in understanding the complexity of hazard evaluation, from inventory to susceptibility and frequency/magnitude or triggering thresholds and their return periods were studied: predisposition traits (structure, lithology, terrain/elevation models), preparing conditions (neotectonics, seismicity, human influence, climate variability), triggering factors (precipitation and climate change, earthquakes, anthropic activities), landslide inventories (graphic representations and spatio-temporal coverage), susceptibility modelling (in terms of methods, purpose, units, validation methods, existence of sensitivity analysis), triggering thresholds (scale, typologically-adapted or not, theoretical/validated, recurrences, EWS or  forecast systems) and hazard evaluation (scale, typologically-adapted or not, theoretical/validated, expressed in terms of  susceptibility, relative hazard or hazard). The purpose of this paper is to harmonize for the first time at the entire mountain chain’s continental scale the information concerning the role of deep-seated landslides inside the complex hazard assessment framework. A special attention is directed towards climate variability/change related implications, since the Carpathians, through their more internal, continental position, are representing a key environment for the assessment of continental climate change adaptation strategies.

Climate-driven transitions in Arctic soil states, from frozen to intermediate and thawed conditions, pose significant threats to slope stability in permafrost regions. As permafrost degrades, slope structural integrity weakens, elevating landslide risk and other geohazards. This study analyzes long-term trends in soil freeze-thaw dynamics across the Arctic to identify areas vulnerable to future slope instability and inform infrastructure planning, resource management, and hazard mitigation strategies.We utilized SMOS brightness temperature data from the CATDS dataset and SMOS L3 Freeze-Thaw State products from ESA, analyzing normalized polarization ratio (NPR) and freeze-intermediate-thaw (FT) classifications from both ascending and descending orbits. Trend detection employed two complementary approaches: the Mann-Kendall non-parametric test for monotonic trends and Long Short-Term Memory (LSTM) neural networks for capturing complex temporal patterns. Analyses were conducted at monthly and seasonal scales across individual pixels and spatial clusters (3×3, 5×5, and 7×7 pixels).Results reveal pronounced changes clustered in northern Canada, Alaska, Siberia, and Arctic Ocean coastal zones. These regions display heterogeneous patterns reflecting localized frost condition shifts. Northern Canada and Alaska show trends consistent with permafrost degradation driven by rising temperatures and seasonal frost variations. Siberian trends suggest accelerating permafrost thaw with implications for carbon release, ecosystem function, and infrastructure integrity. Coastal Arctic zones exhibit changes linked to sea ice retreat, coastal erosion, and permafrost-climate interactions.This research demonstrates the value of combining statistical and artificial intelligence methods to monitor environmental change in permafrost landscapes, providing critical insights for understanding slope instability drivers in a warming Arctic.Acknowledgement: This work was supported by the European Union's Horizon 2020 programme (Grant No. 101086386, EO-PERSIST).