Alan Dykes

Kingston University, London, Department of Civil Engineering, Surveying and Construction Management, Faculty Member

Followers

Following

Co-authors

Public Views

Interests

Uploads

Papers by Alan Dykes

Introduction - Land use change in the tropics: Causes, consequences and monitoring in Mexico: Introduction - Land use change in the tropics

Singapore Journal of Tropical Geography, Jul 1, 2010

The use of salt dilution gauging techniques: ecological considerations and insights

Water Research, Jul 1, 2002

The salt dilution (gulp injection) technique is a well established and widely used technique to m... more The salt dilution (gulp injection) technique is a well established and widely used technique to measure stream discharge, flow velocity and water residence characteristics in small headwater streams. However, the impact of the technique on water quality and instream ecology has been largely ignored in field investigations. A series of experiments were undertaken in a regulated and groundwater-dominated river to examine the effects on aquatic invertebrate drift at high, medium and low discharges. In the groundwater-dominated river, drift significantly increased as a result of the introduction of the saline solution under all flows. Drift increased at the regulated site under low and intermediate flow but not during high flows, probably due to a natural increase in drift associated with spate conditions. Following the application of the saline solution several taxa absent or infrequently occurring in background samples, such as the cased caddisfly, Agapetus fuscipes, were recorded. The wider implications of the technique are discussed in relation to short-term pulsed pollution episodes and the management of riverine ecosystems.

Landslides in blanket peat on subantarctic islands: Causes, characteristics and global significance

Geomorphology, Sep 8, 2010

Blanket peat on hillslopes in the British Isles is known to be susceptible to mass movements. A f... more Blanket peat on hillslopes in the British Isles is known to be susceptible to mass movements. A few such peat landslides had also been reported from southern hemisphere islands with climates that favour the formation of blanket bogs. Previous studies of peat landslides on subantarctic islands are re-examined to address two primary hypotheses: (i) that landslides in blanket peat are

Peat slope failures and other mass movements in western Ireland, August 2008

Quarterly Journal of Engineering Geology and Hydrogeology, Feb 1, 2011

Abstract Peat mass movements are relatively common in Ireland and potentially highly damaging. Th... more Abstract Peat mass movements are relatively common in Ireland and potentially highly damaging. They are usually triggered by heavy rainfall but occasionally wind farm construction or other construction activities also cause significant peat slope failures. In August 2008, heavy rainfall in northwestern Ireland triggered several landslides near Geevagh, Co. Sligo, mostly involving peat-covered hillslopes, and a large peat flow occurred a few days later at the site of a new wind farm near Tralee, Co. Kerry. All were inspected very soon after they occurred to obtain visual evidence of site characteristics and conditions as little changed as possible from the time of failure. This paper reports the nature and implications of the landslides and highlights some of the difficulties of assessing potential landslide hazards from Irish blanket bogs.

Introduction - Understanding and managing landscape change through multiple lenses

(A Festschrift in Memory of Professor John B. Thornes), 2015

The twenty-first century is when everything changes. And we must be ready.

Download

Environmental change and landslide hazards in Mexico

Monitoring and Modelling Dynamic Environments, 2015

Introduction - Land use change in the tropics: Causes, consequences and monitoring in Mexico

Singapore Journal of Tropical Geography, 2010

Reply to discussion on ‘Peat slope failures and other mass movements in western Ireland, August 2008’ by A. P. Dykes & P. Jennings Quarterly Journal of Engineering Geology and Hydrogeology , 44, 5–16

Quarterly Journal of Engineering Geology and Hydrogeology, 2011

We thank Long & Boylan for their interest in our paper (Dykes & Jennings 2011) and for ta... more We thank Long & Boylan for their interest in our paper (Dykes & Jennings 2011) and for taking the trouble to comment on it. Indeed, their more detailed account of the rainfall at Tralee, near the large peat flow at Ballincollig Hill, is both relevant and informative. Our comment that ‘there was no triggering rainfall event for this landslide’ assumed the definition of a landslide ‘trigger’ to be a very short-term (seconds to hours) high-magnitude external disturbing influence that is immediately followed by the initiation of failure. In the absence of any evidence of excessive drying owing to prolonged dry summer weather, we implicitly assumed the peat to be in its normal (near-) saturated condition. The observations by Long & Boylan are of course entirely valid for this condition. The definition of what constitutes a ‘triggering rainfall event’ for a landslide is perhaps worthy of further consideration given that in some hillslope systems there may be a significant delay between a rainfall event and the development of pore water pressures in some critical configuration to initiate failure. This is more likely in bedrock landslides associated with deep water tables than in shallow hillslope systems. However, there are a few examples of blanket peat landslides in Ireland that were not triggered by a specific heavy rainfall event (Hendrick 1990; Wilson & Hegarty 1993). In particular, the 1984 Straduff Townland bogflow mentioned in our paper, which occurred after only 25 mm of rain falling over 3 days (Alexander et al . 1986), indicates the possibility of such delayed …

Landslides in the Tandayapa Valley, northern Andes, Ecuador: implications for landform development in humid and tectonically active mountain ranges

Landslides, 2007

Landslides are common throughout the Ecuadorian Andes, but their causal and controlling factors a... more Landslides are common throughout the Ecuadorian Andes, but their causal and controlling factors and their roles in landform development have not yet been systematically investigated. This paper reports observations and hypotheses arising from a reconnaissance study of the Tandayapa Valley in the Cordillera Occidental, approximately 30 km west of Quito. This study area is characterised by high local relief (ca. 800 m)

The liquid limit of peat and its application to the understanding of Irish blanket bog failures

Landslides, 2006

Catastrophic failures of blanket bogs, involving the escape and outflow of large volumes of semi-... more Catastrophic failures of blanket bogs, involving the escape and outflow of large volumes of semi-liquid basal peat, are well-known phenomena in Ireland but have only very rarely been reported from elsewhere in the world. Their precise causes and mechanisms are as yet unclear. The liquid limit (w L) was identified as a potentially useful indicator of the susceptibility of peat

Caspian sea level change impacts regional seismicity

by Edward N Bromhead and Alan Dykes

Journal of Great Lakes Research, 2012

ABSTRACT

Landslides in blanket peat on subantarctic islands: Causes, characteristics and global significance

Geomorphology, 2010

The Niah Cave Project: the fourth (2003) season of fieldwork

Sarawak museum journal, 2003

RefDoc Refdoc est un service / is powered by. ...

Significance of geomorphological and subsurface drainage controls on failures of peat-covered hillslopes triggered by extreme rainfall

Earth Surface Processes and Landforms, Oct 30, 2007

On 19 September 2003, 40 landslides of 140–18 000 m3 volume occurred within 2·5 km2 on the slopes... more On 19 September 2003, 40 landslides of 140–18 000 m3 volume occurred within 2·5 km2 on the slopes of Dooncarton Mountain (Republic of Ireland) during a storm that may have exceeded 90 mm within 90 minutes. The landslides were investigated to determine the reasons for such a high density of slope failures. All of the landslides were surveyed within four months, and nine of them were investigated in detail. The six largest landslides, all peat failures, accounted for 57% of the more than 100 000 m3 of material displaced during the event. A consistent sequence of superficial materials was found on the failed hillslopes, including an extensive iron pan at the base of a buried soil horizon 0·3 m below the base of the peat. Morphologically, almost all of the landslides occurred on steep planar slopes or around sharp convexities, with the latter failures developing retrogressively upslope. The only significant relationship found from analysis of 371 subsurface pipes and 142 seepage cracks (defined here as contiguous fissures conducting concentrated subsurface flow) across all the failures was that the thinner the peat cover, the deeper the pipes and seepage cracks occurred below the base of peat. It is concluded that most of the landslides were probably caused by a combination of excess water pressures in the buried soil horizon and the thinner overburden of peat or peaty soil associated with the steeper slope segments. Pipes and seepage cracks formed on the iron pan probably existed prior to the failure event and may have contributed to the high water pressures as rainwater inputs exceeded their discharge capacities. One large peat slide was probably triggered by excess water pressures developed within and between artificial tine cuts. The properties of the blanket peat were generally of little consequence in the occurrence of the landslides, but relict desiccation cracks and other structural weaknesses through the peat mass were probably highly significant. Although several aspects of the peat failures correspond to previously published examples, the context of these failures in terms of the topography and upland catena is distinctive. Copyright © 2007 John Wiley &amp; Sons, Ltd.

UV-fluorescence microscopy and the coherence of pollen assemblages in environmental archaeology and Quaternary geology

Journal of Archaeological Science, 2007

UV-fluorescence microscopy provides a powerful tool for the assessment of the coherence of pollen... more UV-fluorescence microscopy provides a powerful tool for the assessment of the coherence of pollen and organic-walled microfossil assemblages in situations where recycling or the intrusion of younger pollen is suspected. It also provides sensitive information about the thermal maturity of pollen, important for assessing whether material has been heated. Examples are given from the Palaeolithic sites at Barnham, Suffolk, UK;

The geomorphology of the Great Cave

ABSTRACT

Geomorphological and subsurface drainage controls on failures of peat-covered hillslopes triggered by extreme rainfall

A geomorphological reconnaissance of structurally-controlled landslides in the Dolomites

Italian Journal of Engineering Geology and Environment

Failure of peat-covered hillslopes at Pollatomish, Co. Mayo, Ireland: analysis of topographic and geotechnical factors

Geomorphological maps of Irish peat landslides created using hand-held GPS

Journal of Maps, 2008

Within about 100 km (by road) from Longarone and Vaiont, many landslides of many different types ... more Within about 100 km (by road) from Longarone and Vaiont, many landslides of many different types and characteristics can be readily identified and accessed. In general, the different types can be clearly associated with their respective topographic and geological contexts. Those associated with 'soft rocks' are found at the southern edge of the Dolomites region and within the northern half of the region, where the respective lithologies generally underlie more gentle slopes below prominent limestone outcrops. Small shallow slides and extensive landslides, including the Tambre and Tessina earthflows, occur in the Eocene flysch in the Alpago Basin at the eastern end of the Belluno Trough. The mid-slopes of the Alpago Basin are also characterised by the forms of deep-seated rotational and/or compound slides in the flysch. Further northeast, the soft mudrocks such as those of the San Cassiano Formation have given rise to many mass movements including the Corvara earthflow and the shallow landslides in and around Cortina d'Ampezzo, as well as shallow rotational slides and deep-seated rotational or compound slides involving failure within the mudrocks resulting in major displacements of the overlying limestones. The upper valley slopes immediately west of the Gardena Pass are characterised by very large tension cracks and subsided limestone blocks that can be categorised as 'cambering' failures, again due to failure of the weaker underlying San Cassiano Formation. Landslides founded entirely in the limestones/dolostones have occurred as far south as the ancient Piave

Download

Alan Dykes

Uploads

Papers by Alan Dykes

Log In