Search Results (62)

Exploring crevasses in extreme environments such as Antarctica is highly dangerous yet essential for ensuring safe movement. Recently, robotic systems have been investigated as a means to conduct exploration in such regions. Unlike conventional settings, these environments require integrated capabilities, including mobility in harsh terrain and the ability to operate reliably at extremely low temperatures. In this paper, we propose KAREX (Korea Antarctic Robot EXplorer), a robotic exploration system designed to investigate crevasses and support research activities in extreme environments. The robot is engineered for cold resistance with thermal insulation that enables low-power temperature maintenance, and it supports multiple swappable batteries for extended-range operation. The proposed system was tested at Jang Bogo Station in Antarctica to verify its performance and applicability in real-world extreme conditions. Full article

A forty-year record (1984–2023) of glacier mass balance and areal extent measurement documented the decline and loss of the Ice Worm Glacier in the North Cascade Range, Washington. After a period of minor variations from 1944 to 1986, the glacier lost 83% of its area from 1986 to 2023 and had a cumulative mass loss of −31.5 m w.e. In 2023, the area at 32,000 m² and the majority of the ice thickness at 2–10 m was insufficient to generate movement. The bottom of the glacier was observed in all existing crevasse features, and stream channels in 2023 at depths of 2–10 m. An ice cave extended the length of the glacier in 2024 illustrating an ice thickness of less than 8 m. This glacier area loss has led to declining glacier runoff into Hyas Creek and the Cle Elum River. Full article

Because fossilized skeletal remains and enclosing sedimentary rocks experience similar diagenetic conditions (i.e., temperature, pressure, and pore fluid interaction,) enclosing sedimentary rocks may provide insight into bone diagenesis. A fossil assemblage, including in situ dinosaur fossils, was discovered in Makoshika State Park near Glendive, MT. Fossil-bearing sandstone is a crevasse splay deposit, and fossils show no sorting or preferred orientation. Bone-bearing sandstone exhibits evidence for intense diagenesis, suggesting a maximum temperature of ~90 °C. Concretion associated with fossils includes two distinctive matrices: dark- and light-colored matrices. Another concretion was found in channel sandstone near the base of the outcrop. These carbonate phases have distinctive isotopic compositions; δ¹³C values for dark-colored matrices, light-colored matrices, and spheroidal concretion are −7.5, 2.1, and −22.4‰ (VPDB), respectively, and their δ¹⁸O values are 16.4, 25.9, and 17.8‰ (VSMOW), respectively. In contrast, fossilized bone δ¹³C and δ¹⁸O values were −4.4‰ (VPDB) and 20.6‰ (VSMOW), respectively, suggesting fractionation with pore fluid was limited. Early carbonate precipitation evidenced by grain coating may have reduced interaction between pore fluids and fossils. Although concretion formation and permineralization do not appear to directly aid in fossil preservation, concretions preserve valuable evidence for diagenetic history. Full article

This paper deals with the problem of multi-robot task scheduling in the Antarctic environments with crevasses. Because the crevasses may cause hazardous situations when robots are operated in the Antarctic environments, robot navigation should be planned to safely avoid the positions of crevasses. However, the positions of the crevasses may be inaccurately measured due to the lack of sensor performance, the asymmetry of sensor data, and the possibility of crevasses drifting irregularly as time passes. To overcome these uncertain and asymmetric problems, this paper proposes a probabilistic multi-robot task scheduling method based on the Nearest Neighbors Test (NNT) algorithm and the probabilistic modeling of the positions of crevasses. The proposed method was tested with a Google map of the Antarctic environments and showed a better performance than the Ant Colony Optimization (ACO) algorithm and the Genetic Algorithm (GA) in the context of total cost and computational time. Full article

Maritime glaciers in the southeastern Tibetan Plateau (SETP) are particularly sensitive to changes in climate, and their changes directly and severely affect regional water security and glacier-related hazards. Given their large societal importance, a better understanding of the mass balance of maritime glaciers in the SETP, a key variable for characterizing the state of glacier health, is of great scientific interest. In this review, we synthesize in situ, satellite-based observations and simulations that present an overall accelerating negative mass balance of maritime glaciers in the SETP in recent decades. We hereby highlight a significant spatiotemporal difference in the mass balance of maritime glaciers across the SETP and investigate the drivers of the accelerated mass loss of these glaciers in recent years. We find that accelerated glacier mass loss agrees with the variabilities in temperatures rising and precipitation decreasing at regional scales, as well as the spatial patterns of widespread melt hotspots (e.g., thin debris, ice cliffs, supraglacial ponds, and surface streams), the expansion of glacial lakes, enlarged ice crevasses, and frequent ice avalanches. Finally, the challenges of the mass balance study of maritime glaciers and future perspectives are proposed. Our review confirms the urgent need to improve the existing glacier inventory and establish comprehensive monitoring networks in data-scarce glacierized catchments, and it suggests paying particular attention to the development of glacier mass-balance models that coupe multiple physical processes at different interfaces to predict the status of maritime glaciers and their responses to climate change. This study can inform the sustainable management of water resources and the assessment of socio-economic vulnerability due to glacier-related hazards in the SETP and its surroundings in the context of marked atmospheric warming. Full article

Assessment of landslide hazards often depends on the ability to track possible changes in natural slopes. To that end, historical air photos can be useful, particularly when slope stability is compromised by visible cracking. Undocumented landsliding rejuvenates a paleo-landslide on a busy motorway connecting Jerusalem to a small Jewish settlement. Recently, a plan for broadening the motorway was approved, and we were asked to study the hazards of the road by Israeli NGOs and Palestinian residents of the area. We captured high-resolution topography around the unstable slope using drone-borne photogrammetry and LiDAR surveys. The modern data allow us to analyze historic air photos and topo maps to assess the level of sliding prior to and during modern landscaping. Our results indicate horizontal offsets of ~0.9–1.8 m and vertical offsets of 1.54–2.95 m at selected sites. We next assess the possible role of anthropogenic versus natural factors in compromising slope stability. We analyze monthly rain records together with seismic catalogs spanning several decades. Shortly after the motorway construction in 1995, a January 1996 rainstorm triggered a massive rockfall. The rockfall blocked traffic with up to 4 m-diameter boulders. We found that while a certain level of rain is a necessary condition for mobilizing the rock mass, it is the anthropogenic intervention that caused the rockfall in this site. We conclude that the recent plan for broadening the motorway jeopardizes the lives of vehicle passengers and the lives of future residents should the development materialize. Full article

This paper introduces a UWB-based human-following system for polar-exploration robots, integrating obstacle and crevasse avoidance functions to enhance the safety and efficiency of explorers in extreme environments. The proposed system determines the relative position of the explorer using UWB anchors and tags. It also utilizes real-time local obstacle mapping and path-planning algorithms to find safe paths that avoid collisions with obstacles. Simulation and real-world experiments confirm that the proposed system operates effectively in polar environments, reducing the operational burden on explorers and increasing mission success rates. Full article

The Upper Miocene–Pliocene Kampungbaru Formation crops out in the easternmost part of the Lower Kutai Basin, Indonesia. The sedimentological analysis of seven outcrops was carried out, and a total of twenty-five samples from these outcrops was analyzed for bulk geochemistry, organic petrography, and bulk and clay mineralogy to assess the effect of the climate and depositional environment on organic matter enrichment. The Kampungbaru Formation consists of interbedded sandstone, siltstone, claystone, and thick coal beds, which were classified into eleven lithofacies. Subsequently, seven facies associations were identified, namely the fluvial-dominated distributary channel, sheet-like sandstone, tide-influenced distributary channel, mouth bar, crevasse splay, delta plain, and delta front. The coal facies generally have a high amount of total organic carbon (TOC, 5.1–16.9; avg. 10.11 wt.%), and non-coal layers range from 0.03 to 4.22 wt.% (avg. 1.54 wt.%). The dominant maceral is vitrinite, while liptinite occurs only rarely in the samples. Organic matter is inferred to have originated from terrestrial plants growing in mangrove swamps. Identified clay minerals include varying proportions of kaolinite, illite, chlorite, and mixed layer illite/smectite (I/S). Kaolinite, which commonly constitutes up to 30% of the clay volume, indicates intensive chemical weathering during a warm and humid climate. In accordance with the Köppen climate classification, the paleoclimate during the deposition of the Kampungbaru Formation is classified as type Af, which is a tropical rainforest. Tropical climate was favorable for the growth of higher plants and deposition of organic matter under anoxic conditions and led to higher amounts of TOC in the Kampungbaru Formation. Full article

The objectives of this paper are to investigate the trade-offs between a physically constrained neural network and a deep, convolutional neural network and to design a combined ML approach (“VarioCNN”). Our solution is provided in the framework of a cyberinfrastructure that includes a newly designed ML software, GEOCLASS-image (v1.0), modern high-resolution satellite image data sets (Maxar WorldView data), and instructions/descriptions that may facilitate solving similar spatial classification problems. Combining the advantages of the physically-driven connectionist-geostatistical classification method with those of an efficient CNN, VarioCNN provides a means for rapid and efficient extraction of complex geophysical information from submeter resolution satellite imagery. A retraining loop overcomes the difficulties of creating a labeled training data set. Computational analyses and developments are centered on a specific, but generalizable, geophysical problem: The classification of crevasse types that form during the surge of a glacier system. A surge is a glacial catastrophe, an acceleration of a glacier to typically 100–200 times its normal velocity. GEOCLASS-image is applied to study the current (2016-2024) surge in the Negribreen Glacier System, Svalbard. The geophysical result is a description of the structural evolution and expansion of the surge, based on crevasse types that capture ice deformation in six simplified classes. Full article

Sedimentary organic matter concentrated in source rocks forms the main source for the formation of hydrocarbons. Its deposition and preservation are strongly controlled by the depositional environment and paleoclimate. This study evaluates the paleoenvironment and the paleoclimatic controls of sediments in the Middle Miocene Balikpapan Group, Mahakam Delta of the Lower Kutai Basin, Indonesia. The sedimentary succession of the Mentawir Formation, encountered in three wells (MHK 1, MHK 3, and MHK 4), contains interbedded sandstones, siltstones, shales, and coal. Gamma ray log analysis has revealed four facies associations: (a) funnel-, (b) bell-, (c) cylindrical-, and (d) bow-shaped patterns, which, together with sedimentological and mineralogical analysis, suggest a fluvio-deltaic depositional environment during the Middle Miocene in the study area. Sedimentary successions from wells MHK 1 and MHK 3 comprise interbedded sandstone and siltstones and are interpreted to represent repeatedly occurring delta plain, delta front, and prodelta deposits. The succession encountered in well MHK 4 mostly consists of amalgamated sandstones and indicates a predominantly fluvial to upper delta plain environment with distributary channels and crevasse splays interbedded with only thin delta front deposits. X-ray diffraction–clay fraction analysis shows that the <2 μm clay-sized fraction consists of kaolinite (38%–67%), illite (14%–29%), chlorite (2%–17%), and mixed-layer illite/smectite (I/S) (14%–30%). Kaolinite formation and abundance indicates a hinterland climate classified as type Af (tropical rainforest) and intensive chemical weathering conditions in the source areas related to tropical to sub-tropical climates with high precipitation. Under such climatic conditions, kaolinite and I/S mixed-layer minerals are preferentially formed because the characteristic ions, K⁺, Na⁺, Ca²⁺, and Fe²⁺, are leached away. Thus, the production, transport, distribution, and preservation of sedimentary organic matter in the onshore Mentawir Formation of the Balikpapan Group are predominantly controlled by the humid tropical climate and fluvio-deltaic processes. Full article

The origin and dynamics of a 2010 pluvial flood in the valley of a large European river are described. In order to study how local people perceive this catastrophic event a small administrative unit (rural municipality) within the Holocene floodplain (thus flooded to 90%) was chosen. Using a questionnaire a human-research survey was performed in the field among 287 people living in flood-prone areas. Almost half of the interviewees feel safe and do not expect a flood recurrence (interpreted as a levee effect). Seventeen percent believe the levee was intentionally breached due to political issues. Six percent of interviewees link the breach with small mammals using levees as a habitat, e.g., beavers, moles, and foxes. The sex and age of interviewees are related to these opinions. Most interviewees (39%) think that flooding was a result of embankment (dyke) instability. The spatial distribution of the survey results are analyzed. Maps presenting: inundation height, economic loss, attitude to geohazards and perception of possible flood recurrence were drawn. Causes of the flood as viewed by local inhabitants and in the context of the riverine geological setting and its processes are discussed. Particular attention is paid to processes linking the levee breach location with specific geomorphic features of the Holocene floodplain. A wide perspective of fluvial geomorphology where erosive landforms of crevasse channels (and associated depositional crevasse splays) are indicators of geohazards was adopted. This distinct geomorphological imprint left by overbank flow is considered a natural flood mark. Such an approach is completely neglected by interviewees who overestimate the role of hydrotechnical structures. Full article

Initiating event analysis is an essential prerequisite of conducting probabilistic safety assessment for nuclear reactors, which plays an important role in improving the core design, identifying fault, and guiding operation. In order to determine the initiating event list of SIMONS (Small Innovative helium-xenon cooled Mobile Nuclear power System), preliminary researches on the initial event of SIMONS were carried out using the MLD (Main Logic Diagram) analysis method and referring to the initial event list and initial event analysis theory of other nuclear reactors such as HTGR (High Temperature Gas-cooled Reactor), MSR (Molten Salt Reactor), and PWR (Pressurized water reactor). With employing these methods, a total of 31 initial events are identified for SIMONS based on its latest conceptual design. These initial events are then divided into six groups according to the accident types, which are core heat removal increase, core heat removal decrease, abnormal reactivity and power distribution, pipeline crevasse and equipment leakage, anticipated transients without scram, and disasters (internal and external). The obtained results can provide a theoretical basis for the further safety analysis of SIMONS. Full article

The glacial and torrential basin of Taconnaz (Mont-Blanc massif, France) dominates the Chamonix valley. It is one of the major paths for snow avalanches in the Alps, often triggered by serac falls from the Taconnaz glacier. On 24 November 2018, the basin’s multi-risk nature was further accentuated by a new type of hazard with a rockfall triggered at c. 2700 m a.s.l. It travelled down over a distance of 1.85 km and stopped 165 m away from the construction site of a micro-hydroelectric power station. We studied the triggering conditions at the permafrost lower limit, the effects of the supra-glacial path on the flow patterns, and the fate of the scar and the deposit on torrential activity. By comparing a pre-event Structure from Motion model with a post-event LiDAR model, we estimated the volume of the scar to be 42,900 m³ (±5%). A numerical model was employed to simulate the rapid runout. It revealed the complexity of the flow, attributed to the sequestration of a part of the deposit in crevasses, the incorporation of a significant volume of ice resulting in a transition from a dry granular flow to a mud-like flow, and the presence of numerous deposit zones. Subsequent monitoring of the area after the event allowed for the documentation of the scar’s evolution, including a landslide, as well as the progressive degradation and evacuation of the deposit by the torrent without producing debris flow. The study of the triggering factors indicated glacial retreat as the probable main cause, assisted by the melting of ice lenses left by the permafrost disappearance. Finally, we present replicable methods for managing risks at the site following the event. This event improves the understanding of cascading processes that increasingly impact Alpine areas in the context of climate change. Full article

The physical and biological structure of riparian vegetation fundamentally influences floodplain roughness, and thus the flood velocity and flood levels of a river. The study aims to provide detailed spatial data on the vegetation density of a floodplain, and to model the effect of the actual vegetation and various scenarios on flow conditions. LiDAR data were applied to evaluate the density and roughness of the submerged understory vegetation over the densely vegetated floodplain of Lower Tisza, Hungary. Then, HEC–RAS 2D modelling was applied to analyse the effect of the actual vegetation on flow conditions. Further scenarios were also created to predict the effect of (i) invasive plant control, (ii) no maintenance, and (iii) riparian vegetation restoration (meadows). According to the results, since the 19th Century, the increased vegetation density is responsible for a 17-cm flood level increase, and if the vegetation grows even denser, a further 7 cm could be expected. As the vegetation density increases, the overbank flow velocity decreases, and the crevasses and flood conveyance zones gradually lose their function. Simultaneously, the flow velocity increases in the channel (from 1 m/s to 1.4 m/s), resulting in an incision. Applying LiDAR-based 2D flow modelling makes it possible to plan sustainable riparian vegetation maintenance (e.g., forestry, invasive species clearance) from both ecology and flood control perspectives. Full article

Cross-correlation of image-pairs derived from both optical and synthetic aperture radar satellite imagery is the most common technique for measuring glacier flow velocity and quantifying the dynamics and discharge of glaciers. While the technique has been shown to be effective on polar ice sheets, the accuracy of satellite-derived velocities in temperate alpine regions is poorly constrained. Flow velocities were measured in situ using an RTK-GPS along four profiles on Taku, Matthes, Vaughan-Lewis, and Llewellyn Glaciers in southeast Alaska from 2016 through 2018. These GNSS-measured velocities were correlated against spatially coincident and contemporaneous satellite-derived velocity datasets, including both versions 1 and 2 of ITS_LIVE and velocities determined by offset tracking of SAR data in the Sentinel Application Platform (SNAP) and GAMMA (RETREAT dataset). Significant gaps in velocity maps derived from optical imagery (Landsat/Sentinel-2) were observed and determined to be due to low coherence rather than cloud contamination. Cross-correlation of SAR data (Sentinel-1) in SNAP and RETREAT achieved better accuracy compared to optical, although a strong dichotomy in performance was observed. SAR-derived velocities in the accumulation zone and transient snowline area showed overall poor correlation to GNSS-measured velocities that were likely due to significant shifts in the backscatter amplitude of the homogenous, snow-covered surface, although both SAR-derived SNAP and RETREAT velocities were anomalously accurate where GNSS velocities were below 0.10 m/day along the glacier margins. SNAP and RETREAT achieved the most accurate results in the study in the ablation zone of the Llewellyn Glacier where stable backscatter targets on the glacier surface (crevasses, supraglacial debris) facilitated high coherence in the cross-correlation procedure. SAR data are likely the most suitable for the derivation of satellite-derived velocities on temperate alpine glaciers, particularly in slow-moving and ablation zones, but should be subject to scrutiny for fast-flowing glaciers and those with an active hydrologic surface system. Full article