Viola Maria Bruschi

Geomorphological map of the NW Coast of the Island of Malta (Mediterranean Sea)

This paper presents the results of geomorphological investigations carried along the north-western coast of the Island of Malta. Field surveys, accompanied by aerial photo-interpretation, have led to the production of a geomorphological map at 1:7500 scale which outlines the main processes and related landforms. The latter are the result of the complex interplay of structural, gravitational, coastal and karst processes. Particular attention was devoted to the recognition, identification and mapping of landslides which affect large coastal sectors of the study area, locally giving rise to hazardous conditions.

Land management versus natural factors in land instability: some examples in northern Spain.

The objective of this work is to test a hypothesis formulated on the basis of former results which considers that there might be a “global geomorphic change,” due to activities related to land management and not determined by climate change, which could be causing an acceleration of geomorphic processes. Possible relationships between some geomorphic processes related to land instability (landslides or sediment generation) and potential triggering factors are analyzed in study areas in northern Spain. The analysis is based on landslide inventories covering different periods, as well as the determination of sedimentation rates. Temporal landslide and sedimentation rate trends are compared with different indicators of human activities (land-use change, logging, forest fires) and with potential natural triggers (rainfall, seismicity). The possible influence of the road network in the distribution of landslides is also analyzed. Results obtained show that there is a general increase of both landslide and sedimentation rates with time that cannot be explained satisfactorily by observed rainfall trends and even less by seismicity. Land-use change appears to be by far the main factor leading to land instability, with some changes producing up to a 12-fold increase of landslide rate. A relationship between road network and the spatial distribution of landslides has also been observed. These results do confirm the existence of an acceleration of geomorphic processes in the region, and also suggest that climate-related factors play a limited role in the changes observed.

Landslides Along the North-West Coast of the Island of Malta

The paper shows the results of geomorphological and engineering-geological investigations carried out along the north-western coast of the Island of Malta, with special emphasis on landslides. Field surveys and aerial-photo interpretation allowed the recognition, identification and mapping of a series of landslides of different type and size, some of which showing evidence of activity. Coastal instability in the studied area is deeply controlled by structural factors, such as tectonic and stratigraphic ones. The research envisaged a multidisciplinary approach, which also included landslide monitoring in specific sites which were selected for detailed investigations, owing to the peculiarity of the instability processes occurring and for the related hazard and risk conditions. The paper outlines the research phases and the results achieved which proved to be fruitful thanks to the application of different methodologies for the study of coastal landslides. Particular attention has been paid to rock spreading phenomena, which are widespread along the north-western coast of Malta due to the superimposition of limestones over clayey terrains.

Geomorphic Hazards in Spain

An overview of the main geomorphic hazards in Spain is presented. For each one of the processes analysed (floods, landslides, sinkholes, and coastal hazards), a brief description of their distribution, socioeconomic effects, and main causes is given. The main lines of research undertaken in recent times on these hazards, including development of new tools or techniques, are discussed. Finally, legislation and land-use planning measures for mitigation of risks due to such processes are described.

Geomorphological features of the Rio della Rocca valley (northern Apennines, Italy)

This paper presents a geomorphological map of the Rio della Rocca valley, a small catchment located in the lower Apennines of the Province of Reggio Emilia (northern Italy). The geomorphological map has been produced at a scale 1:7500 as a base document within multidisciplinary investigations aimed at the rehabilitation of the area, which is characterised by peculiar geological and geomorphological features and a high scenic value, despite clear evidence of human impact. Since the mid 1950s the valley has been affected by quarrying activities which in some places have deeply changed its environmental and, in particular, geomorphological features. As a part of the research, geomorphological survey and mapping were carried out in order to detect the main slope instability and erosional processes and landforms and, at the same time, to recognise sites of geological and geomorphological interest. Proposals for territorial development have been proposed which take into account geotourism and recreational issues.

An Application of Computer Graphics for Landscape Impact Assessment

This communication shows a procedure aimed at assisting in the assessment of the landscape impact caused by new lineal infrastructure services, such as motorways. The computer simulation has demanded the idealisation of the phenomenon to be graphically represented, its theoretical model and the functional analysis of the computational tool that can aid in finding a solution. The core of the problem is that there is a non finite set of landscapes to be considered (and analysed); however, according to the model proposed, if some suitable Computer Graphics libraries are used, it is possible to automatically produce a reduced catalogue of realistic images simulating, each of them, the effect that the new infrastructure will cause on the environment, just at the sites where the landscape results to be more vulnerable.

Geoheritage and Environmental Impact Assessment (EIA)

Abstract Geoheritage represents an important part of natural and cultural heritage, and provides society with a broad range of services that are fundamental for its socioeconomic development. Due to its nature, geoheritage constitutes a nonrenewable resource; thus, natural processes and human activities can produce a partial or total loss of such heritage and associated services. In order to achieve the protection and conservation of geoheritage, one strategy is the identification and estimation of the probable impacts produced by human activity, with the objective of designing mitigation measures. Environmental Impact Assessment (EIA) represents the best tool to reach these objectives. Even though this procedure has existed since the end of the 1960s and is now being practised in many countries, the integration of geoheritage into EIA is not yet satisfactory. Some efforts were made at the end of 20th century, but methodologies for the integration of geoheritage in the EIA procedures are still very limited.

Landslide Hazard Scenarios Based on Both Past Landslides and Precipitation

The goal of this contribution is to develop a set of methods and techniques for modelling landslide hazard, in order to obtain better predictions and, therefore, to reduce the risk associated to this type of process. The research has been carried out in North-Western Guipuzcoa (Spain), an area intensely affected by shallow landslides. Hazard predictions must be based on several assumptions, termed scenarios. To propose more realistic hazard scenarios, two different approaches have been applied: on one hand, by extrapolating the trends observed from recent past landslide activity and, on the other hand and indirectly, from the empirical analyses between landslides and their main trigger (precipitation). It was necessary to get long time series of landslide occurrences, through which sound future frequency could be estimated and relationships between landslides and their predisposing factors established. The landslide inventory includes 20 time intervals ranging from the 50s of last century to the present and has been obtained by analyzing photographic images from different dates. Rainfall records of several weather stations have been analyzed, establishing correlations between landslides and precipitation intensity-duration. According to rainfall quantity, duration and intensity, as well as landslide activity, six multiple occurrence regional landslide events (MORLE), regarding rainfall extreme events, have been identified and characterized. On the basis of both types of scenarios quantitative hazard models could be obtained.

A Comprehensive Approach to Investigate Maltese Coastal Landslides

ABSTRACT SOLDATI, M., BONACHEA, J., BRUSCHI, M.V., CORATZA, P., DEVOTO, S., GONZÁLEZ-DIAZ, A., MANTOVANI, M., PASUTO, A., PIACENTINI, D., REMONDO, J and SCHEMBRI, J.A., 2011. A Comprehensive Approach to Investigate Maltese Coastal Landslides. In: Micallef, A. (ed.), MCRR3-2010 Conference Proceedings, Journal of Coastal Research, Special Issue, No. 61, pp. 472–473. Grosseto, Tuscany, Italy, ISSN 0749-0208. This paper presents geomorphological and engineering-geological studies carried out along the north-western coast of Malta by research groups belonging to the University of Modena and Reggio Emilia (Italy), the National Research Council (Italy), the University of Malta and the University of Cantabria (Spain). The research are funded by Fondazione Cassa di Risparmio di Modena and the European Centre for Geomorphological Hazards (CERG) and focus on the evolution of coastal landslides with emphasis on the issues of hazard and risk, with respect to the recreational infrastructures present in the area and to the several tourists that visit this stretch of coast. The area of study extends for about 12 km2 in Northern Malta and elevation ranges from the coast to about 110 m above the sea level. In this part of the Island, slope failures are abundant and strictly linked to lithological and structural factors. In fact, in the north-western area of Malta, between Paradise Bay and Gnejna Bay, three geological units outcrop that deeply control the morphological setting and the evolution of landscape: Globigerina Formation, Blue Clay Formation and Upper Coralline Formation. The Upper Coralline Limestone, the younger Formation of Malta Island, forms a karst plateau, bordered by vertical cliffs of varying heights, which ranges from a few meters to 30 m. At the foot of the limestone slopes Blue Clays Formation crops out which develops gently slopes that in some cases can reach directly the sea. The different mechanical behaviour of clays and limestone favours the development of lateral spreading phenomena, which occur in particular at Anchor Bay, at Ghajn Tuffieha Bay and along the western sector of Marfa Ridge. The occurence of this type of mass movement causes the presence of vertical joints and cracks near the calcareous slopes, due to the fragile response of rock material. Properties of the cracks, such as their aperture and persistence, depend on the different stages of lateral spreading phenomena; in the areas where the phase of evolution is more mature fractures reach lengths that can exceed 200 meters. A consequence of the presence of these wide discontinuities is the accumulation of large boulders along the coast, due to the detachament and fall of blocks from the vertical cliffs. The deposits are wide and the blocks are slowly scattered on the large terrace gently sloping towards the sea. In order to study and understand the complex evolution of coastal slope failures, a multidisciplinary approach has been applied and a complex system of monitoring has been installed. The research carried out so far has included a retrospective study of slope instability events along the north-west coast of Malta, collection and analysis of climatic data, multi-temporal analysis of aerial photos, geomorphological survey and mapping. In addition, the research plan foresees LIDAR surveys and radar interferometric analyses. The results obtained have permitted to outline the causes and evolution of coastal landslides in the north-western coast of Malta, with specific focus on rock spreading phenomena whose movement velocity and direction have been monitored since 2006 in two field sites. GPS network are located at Il-Qarraba and Anchor Bay. The analysis of monitoring data has shown that lateral spreading phenomena are active in both sites and that the displacements range from a few mm/yr to more then 3 cm/yr. The integration of new monitoring data to be acquired will permit the evaluation and mapping of landslide hazard. The final results of the research are aiming at providing local authorities with a sound knowledge of coastal instability phenomena which might be useful for future land planning and in managing geomorphological risk issues.

The Cantabrian Rocky Coast

The Cantabrian Coast is located in the Spanish north littoral, in the southeastern sector of the Bay of Biscay (Cantabrian Sea), conforming the northern border of the Regions of Cantabria and Basque Country, the latter matching Biscay and Guipuzcoa provinces (Fig. 4.1). This coastal strip has an obvious strategic and economic interest and concentrates a variety of activities (urban and industrial development, fishing, tourism, commerce, etc.). This has led to a very intense transformation of coastal areas, particularly during the last decades.