Characterisation of the 2020 Drumkeeran peat landslide: a large peat slide in Ireland. 

2021 ◽  
Author(s):  
John Connolly ◽  
Eoghan Holohan ◽  
Mary Bourke ◽  
Charmaine Cruz ◽  
Catherine Farrell ◽  
...  
Keyword(s):  
Volume Ratio ◽  
Thick Layer ◽  
Source Area ◽  
Organic Soils ◽  
Topographic Slope ◽  
Drainage Patterns ◽  
Blanket Bog ◽  
Special Area ◽  
Radar Satellite ◽  
Run Up

<p>Mass movements in peatlands are poorly understood. This is because of the unusual geotechnical properties of the materials (organic soils) and a paucity of well-constrained case studies. At the end of June 2020, a large peat slide occurred on Shass mountain, several kilometres northeast of the village of Drumkeeran in Co. Leitrim, north-western Ireland. The source area of the peat slide is an area of blanket bog within a Special Area of Conservation (SAC). This area is characterised by a topographic slope of 3-5°. On recently published Landslide Susceptibility Maps it was classified as ‘moderately low’ to ‘low’.</p><p>To understand this peat slide’s genesis and impact on the landscape, post-slide site investigations and aerial surveys were undertaken in the following days and weeks. These included: photogrammetry and LiDAR surveys via UAVs and crewed aircraft; Ground Penetrating Radar (GPR) profiling; in-situ peat depth measurements, soil coring and a vegetation survey.  These data were complemented by pre-and post-slide radar satellite data (Sentinel-1) and were compared to high-resolution pre-slide aerial imagery and digital surface models (DSMs) captured in August 2017 and April 2020.</p><p>Mapping and DSM differencing show a source area of 7 ha, from which ~ 171,000 m<sup>3</sup> of peat flowed 6.6 km down a river channel. The height/run-out ratio was 0.035; the run-out/volume ratio was 0.038. Peak flow or run-up heights near the source area were >4 m. Video, field and satellite evidence indicates that the peat was highly liquified. It deposited in three zones: upstream of a small bridge, which acted as a partial dam and on two floodplain areas. About 45 ha were covered with peat up to 1-3 m thick, these deposits generally thin downstream. Radar intensity data support local accounts that most of this material failed retrogressively and redeposited within 24 hours.</p><p>Data from the nearest meteorological station, 27 km to the west, show that the region experienced a relatively dry period (118 mm of precipitation) in the 2.5 months before the landslide, and a period of exceptionally high rainfall (53 mm) three days immediately beforehand. Flow pathway analysis indicates a natural drainage convergence in the upper catchment. The landslide possibly started here and regressed upslope into ~5 ha of well-drained bog, afforested in 1996, located at the head of the catchment. The areas to the south and east comprise of a mosaic flushes, wet heath, and blanket bog vegetation.</p><p>The peat depth was assessed by both GPR data (calibrated by coring), which shows the base of the peat and probing. It ranged from 2-5 m. This accords with a typical 2-4 m thickness of failed peat from DSM differencing. Coring also revealed a ~50cm thick layer clay at the base of the peat. These preliminary results highlight the potential importance of local drainage patterns and localised clay layers in increasing peat-slide susceptibility on low-angle slopes. This characterization underpins further investigation into the multifarious factors causing peat slides, which may be exacerbated by climate change.</p>

scholarly journals 2D Materials for Gas Sensing Applications: A Review on Graphene Oxide, MoS2, WS2 and Phosphorene

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3638 ◽  
Author(s):  
Maurizio Donarelli ◽  
Luca Ottaviano
Keyword(s):  
Graphene Oxide ◽  
Gas Sensing ◽  
2D Materials ◽  
High Surface ◽  
Volume Ratio ◽  
Thick Layer ◽  
Research Field ◽  
First Year ◽  
Sensing Applications ◽  
Recent Developments

After the synthesis of graphene, in the first year of this century, a wide research field on two-dimensional materials opens. 2D materials are characterized by an intrinsic high surface to volume ratio, due to their heights of few atoms, and, differently from graphene, which is a semimetal with zero or near zero bandgap, they usually have a semiconductive nature. These two characteristics make them promising candidate for a new generation of gas sensing devices. Graphene oxide, being an intermediate product of graphene fabrication, has been the first graphene-like material studied and used to detect target gases, followed by MoS2, in the first years of 2010s. Along with MoS2, which is now experiencing a new birth, after its use as a lubricant, other sulfides and selenides (like WS2, WSe2, MoSe2, etc.) have been used for the fabrication of nanoelectronic devices and for gas sensing applications. All these materials show a bandgap, tunable with the number of layers. On the other hand, 2D materials constituted by one atomic species have been synthetized, like phosphorene (one layer of black phosphorous), germanene (one atom thick layer of germanium) and silicone (one atom thick layer of silicon). In this paper, a comprehensive review of 2D materials-based gas sensor is reported, mainly focused on the recent developments of graphene oxide, exfoliated MoS2 and WS2 and phosphorene, for gas detection applications. We will report on their use as sensitive materials for conductometric, capacitive and optical gas sensors, the state of the art and future perspectives.

Geomorphic imprint of dynamic topography and intraplate tectonism in central Australia

2020 ◽  
Author(s):  
John Jansen ◽  
Mike Sandiford ◽  
Toshiyuki Fujioka ◽  
Timothy Cohen ◽  
Martin Struck ◽  
...  
Keyword(s):  
Source Area ◽  
Plate Motion ◽  
Dynamic Topography ◽  
Vertical Movements ◽  
Sediment Dispersal ◽  
Drainage Patterns ◽  
First Case ◽  
Central Australia ◽  
To Come

<p>The mantle convection accompanying plate motion causes vertical movements of up to a few hundred metres at Earth’s surface over wavelengths of 10<sup>2</sup>–10<sup>3</sup> km. This <em>dynamic topography</em> appears to come and go at ~ 1–10 Myr timescales in areas that are often well away from plate margins, although its spatial and temporal characteristics are subject to ongoing debate. Since such motions are small and transient, discriminating convective signals from other drivers of relief generation and/or sediment dispersal remains tricky. An outstanding challenge is to detect these elusive, transient undulations from a tell-tale geomorphic imprint preserved in either drainage patterns or the stratigraphic record.</p><p>In the intra-plate setting of central Australia, a 30 km long sinuous gorge is developed where the major regional drainage, Finke River, dissects a band of low hills. Remarkably, this gorge is intertwined with an abandoned and less deeply incised gorge that forms hanging junctions and shares similar width and sinuosity. This unusual overprinting of the two gorges remains unexplained.</p><p>With an aim to investigate the history of the intertwined gorges, we measured cosmogenic <sup>10</sup>Be and <sup>26</sup>Al in fluvial gravels stored in the palaeovalley cutoffs. The gravels are remnants of major alluviation episodes that we surmise result from ongoing vertical motions associated with dynamic topography. We use a Markov chain Monte Carlo-based inversion model to test two hypotheses to explain the nuclide inventory contained within the stored fluvial gravels. In the first case, rapid alluviation and erosion since 1 Ma preserves the nuclide memory of the source area; in the second, the nuclide memory is erased during long-term fluvial storage (> 5 Myr) and is restored during exhumation of the palaeovalley gravel-pile. The two hypotheses are therefore limiting-case scenarios that constrain overall fast versus slow landscape evolution, respectively. Our model results suggest that long-term burial decouples the source-area signal from nuclide abundances measured in the palaeovalley gravels. This casts events into a Miocene timescale.</p>

The impacts of peat slides on upland blanket peatland hydrology, ecology and soil structure. A paired catchment approach. 

2021 ◽  
Author(s):  
Rob Halpin ◽  
Mary Bourke ◽  
Mike Long ◽  
Andrew Trafford
Keyword(s):  
Soil Structure ◽  
Slope Failure ◽  
Anthropogenic Pressures ◽  
Subsurface Hydrology ◽  
Peatland Hydrology ◽  
Local Erosion ◽  
Blanket Bog ◽  
Special Area ◽  
Paired Catchment ◽  
Initial Results

<p>Rainfall-induced landslides are difficult to forecast and often evolve into highly destructive flows, as such, they are one of the most dangerous natural hazards globally. While our understanding of peatland hydrology has improved greatly in the past two decades, there has been less focus on the response of peat hydrology following perturbations such as wildfires and landslides.  Here we report on a new paired catchment experiment in Ireland. Our focus is to quantify the hydrological changes following peat landslides and further, to establish the short-term and longer-term impacts on local peatland hydrology, ecology and recovery.</p><p>The two paired sites are located in Co. Leitrim, Ireland, in two adjacent, small upland blanket bog catchments. The first peat catchment (0.2km<sup>2</sup>) is an area of a recent (June 2020) slope failure. According to preliminary estimates ~178,000 – 188,000 tonnes of peat were transported downstream during the peat slide event, resulting in a large landslide scar section (~0.059 km<sup>2</sup>) in a special area of conservation [SAC]. Preliminary impacts are assessed to include: habitat loss, decreased slope stability, impacts on hydrology and water quality, as well as increased local erosion.</p><p>This catchment is paired with an adjacent upland blanket peat catchment (0.11 km<sup>2</sup>) which is deemed to have been under the same anthropogenic pressures (grazing, upslope forestry plantation).</p><p>A hydrometric suite, including weather station, piezometers, and water level recorders to evaluate the surface and subsurface hydrology has been installed at both sites. In addition, we are monitoring the response of landslide deposits (e.g. rafted peat, some with still-standing sika spruce), ecology, soil structure, permeability and shear strength in both catchments.</p><p>Here we will report on the initial results of our monitoring.</p>

INFLUENCE OF TRACE ELEMENT FERTILIZATION ON THE DECOMPOSITION RATE AND PHOSPHATASE ACTIVITY OF A MESIC FIBRISOL

1977 ◽  
Vol 57 (4) ◽  
pp. 397-408 ◽  
Author(s):  
S. P. MATHUR ◽  
A. F. RAYMENT
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Organic Soil ◽  
Organic Soils ◽  
Biological Degradation ◽  
Npk Fertilizers ◽  
Temperature Regimes ◽  
Blanket Bog ◽  
Before And After ◽  
The One

Determinations were made of the relative decomposition rates of samples taken from pasture plots on a blanket bog which had been drained, limed and variously fertilized for 8 yr. Under all three temperature regimes of incubations employed in the laboratory, samples of plots receiving fritted trace elements (FTE) and NPK fertilizers lost significantly less (22–29%) carbon than those of plots treated annually only with NPK. Subsequent measurements of bulk densities of the field plots confirmed the mitigating effect of FTE applications on biological degradation and humification of this organic soil. Chemical analyses and preliminary trials indicated that the increased Cu levels in the FTE-treated soils, although obviously not biocidal, may have inactivated some extracellular degradative enzymes in the soil at an accelerated rate, thus slowing degradation. Acid phosphatase activity was studied as an example. Indeed, this activity, both before and after laboratory incubation, was significantly lower in the FTE + NPK-treated material than in the one treated annually with NPK alone. The former also inactivated (in 20 h) 30% more of an added acid phosphatase preparation than did the latter. Also, this and several other organic soils lost significant proportions of their phosphatase activities upon incubation with 0.5% Cu. This treatment with Cu also curtailed the loss of carbon as CO2 from samples of the pasture plots on the Mesic Fibrisol.

scholarly journals The Tsunami Caused by the 30 October 2020 Samos (Aegean Sea) Mw7.0 Earthquake: Hydrodynamic Features, Source Properties and Impact Assessment from Post-Event Field Survey and Video Records

2021 ◽  
Vol 9 (1) ◽  
pp. 68
Author(s):  
Ioanna Triantafyllou ◽  
Marilia Gogou ◽  
Spyridon Mavroulis ◽  
Efthymios Lekkas ◽  
Gerassimos A. Papadopoulos ◽  
...  
Keyword(s):  
Wave Height ◽  
Epicentral Distance ◽  
Source Area ◽  
Aegean Sea ◽  
Tsunami Source ◽  
Western Turkey ◽  
Power Law Decay ◽  
Run Up ◽  
Tsunami Run Up ◽  
Coastal Uplift

The tsunami generated by the offshore Samos Island earthquake (Mw = 7.0, 30 October 2020) is the largest in the Aegean Sea since 1956 CE. Our study was based on field surveys, video records, eyewitness accounts and far-field mareograms. Sea recession was the leading motion in most sites implying wave generation from seismic dislocation. At an epicentral distance of ~12 km (site K4, north Samos), sea recession, followed by extreme wave height (h~3.35 m), occurred 2′ and 4′ after the earthquake, respectively. In K4, the main wave moved obliquely to the coast. These features may reflect coupling of the broadside tsunami with landslide generated tsunami at offshore K4. The generation of an on-shelf edge-wave might be an alternative. A few kilometers from K4, a wave height of ~1 m was measured in several sites, except Vathy bay (east, h = 2 m) and Karlovasi port (west, h = 1.80 m) where the wave amplified. In Vathy bay, two inundations arrived with a time difference of ~19′, the second being the strongest. In Karlovasi, one inundation occurred. In both towns and in western Turkey, material damage was caused in sites with h > 1 m. In other islands, h ≤ 1 m was reported. The h > 0.5 m values follow power-law decay away from the source. We calculated a tsunami magnitude of Mt~7.0, a tsunami source area of 1960 km2 and a displacement amplitude of ~1 m in the tsunami source. A co-seismic 15–25 cm coastal uplift of Samos decreased the tsunami run-up. The early warning message perhaps contributed to decrease the tsunami impact.

Postglacial paleoecology and successional relationships of a bog woodland near Prince Rupert, British Columbia

1983 ◽  
Vol 13 (5) ◽  
pp. 938-947 ◽  
Author(s):  
A. Banner ◽  
J. Pojar ◽  
G. E. Rouse
Keyword(s):  
British Columbia ◽  
North Coast ◽  
Organic Soils ◽  
Site Factors ◽  
Southeast Alaska ◽  
The North ◽  
Drainage Patterns ◽  
Mineral Soils ◽  
Scrub Forest ◽  
Alluvial Forest

The historical development of a bog woodland on the north coast of British Columbia is reconstructed using pollen analysis, peat stratigraphy, and 14C dating. The succession spans 8700 ± 210 years in the following sequence: Pinuscontorta Dougl. – Alnusrubra Bong. – ferns/pioneer alluvial forest; Piceasitchensis (Bong.) Carr. – Alnus – Tsugaheterophylla (Raf.) Sarg. – (Thujaplicata) Donn. – Lysichitonamericanum Hulten & St. John – ferns/moist productive alluvial forest on regosols; Thuja – Chamaecyparisnootkatensis (D. Don) Spach – Tsuga – Pinus/scrub forest on peaty mineral soils; Pinus – Chamaecyparis – ericaceous shrubs – Sphagnum L. spp./bog woodland on organic soils. This ecosystem sequence is correlated with changes in paleoclimate reported for southwestern British Columbia and may also be associated with edaphic factors such as changing drainage patterns, the formation of cemented soil horizons, and the accumulation of thick organic surface horizons. The succession from forest to muskeg is contrasted with other evidence for succession from muskeg to forest in north-coastal British Columbia and southeast Alaska. We interpret the regional vegetation and soils as a dynamic complex of ecosystems linked successionally through climatically sensitive pathways. Local site factors such as topography, landform, drainage, and nutrient regime are important secondary factors controlling the direction of succession.

Late Carboniferous and Early Permian drainage patterns in Atlantic Canada

1992 ◽  
Vol 29 (2) ◽  
pp. 338-352 ◽  
Author(s):  
Martin R. Gibling ◽  
John H. Calder ◽  
Robert Ryan ◽  
H. Walter van de Poll ◽  
Gary M. Yeo
Keyword(s):  
Large Scale ◽  
Source Area ◽  
Late Carboniferous ◽  
Considerable Proportion ◽  
Atlantic Canada ◽  
Early Permian ◽  
Large Area ◽  
Alluvial Deposits ◽  
Drainage Patterns ◽  
Central Appalachians

Paleoflow data have been compiled for Late Carboniferous (late Westphalian A) to Early Permian alluvial deposits over a large area of Atlantic Canada. The data, which include more than 36 000 measurements of large-scale trough cross-strata, indicate a predominantly northeasterly paleoflow, and suggest that a major source area lay to the southwest of the region throughout the 30 Ma period represented. Uplands within the basin deflected paleoflow and probably formed important local drainage and sediment sources. Tectonostratigraphic analysis suggests that the drainage originated in the fold-and-thrust belt of the central Appalachians and parts of the northern Appalachians. Rivers probably followed northeast-oriented structural lineaments through the older Acadian mountains of the northern Appalachians. A considerable proportion of the rising orogen's drainage, and probably detritus, may have traversed basins along the strike of the mountain belt, a situation analogous to that of the modern Himalayas.

scholarly journals The mechanism of landslide-induced debris flow in Geothermal area, Bukit Barisan Mountains of Sumatra, Indonesia

2021 ◽  
Author(s):  
Wahyu Wilopo ◽  
Teuku Faisal Fathani
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Volcanic Rocks ◽  
Thick Layer ◽  
Source Area ◽  
Site Investigation ◽  
Xrd Analysis ◽  
Alluvial Fan ◽  
Mountain Range ◽  
Geothermal Area

Landslides frequently occur in Indonesia, especially in the geothermal areas located on Sumatra's mountainous island. On April 28, 2016, around 04:30 Western Indonesia Time, a landslide-induced debris flow occurred in Lebong District, Bengkulu Province, Indonesia. The source area of the landslide was located at Beriti Hill on the Bukit Barisan Mountain Range. It resulted in 6 fatalities and damage to infrastructures such as geothermal facilities, roads, water pipes, houses, and bridges. Subsequent landslides and debris flows occurred on April 30, May 2, and 3, 2016. Therefore, this study aims to examine the mechanism and to know the most significant contributing factor to the Beriti Hill landslide. Site investigation, soil sampling, XRD analysis, and Lidar analysis were carried out in the research. Beriti Hill is a geothermal area with many manifestations and is composed of volcanic rocks. Alteration processes produced a thick layer of soil from volcanic rocks. The thick soil dominated by clay minerals and steep slopes is the dominant controlling factor of a landslide, triggered by high rainfall intensity. Debris flows are recurring events based on the Air Kotok river's stratigraphic data downstream of the landslide area. The debris flow material is toxic due to the low pH from the geothermal process. Therefore, the alluvial fan deposit area from Beriti Hill debris flow is a hazard zone and unsuitable for settlement and agriculture.

Ultrastructure of the soil fungus, Geomyces pannorus

1984 ◽  
Vol 42 ◽  
pp. 738-739
Author(s):  
J. A. Traquair ◽  
E. G. Kokko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fine Structure ◽  
Low Temperatures ◽  
Soil Fungus ◽  
Organic Soils ◽  
Anatomical Studies ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Scanning Electron

With the advent of improved dehydration techniques, scanning electron microscopy has become routine in anatomical studies of fungi. Fine structure of hyphae and spore surfaces has been illustrated for many hyphomycetes, and yet, the ultrastructure of the ubiquitous soil fungus, Geomyces pannorus (Link) Sigler & Carmichael has been neglected. This presentation shows that scanning and transmission electron microscopical data must be correlated in resolving septal structure and conidial release in G. pannorus.Although it is reported to be cellulolytic but not keratinolytic, G. pannorus is found on human skin, animals, birds, mushrooms, dung, roots, and frozen meat in addition to various organic soils. In fact, it readily adapts to growth at low temperatures.

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