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This contribution is focused on the reconstruction of the geo-environmental evolution during the Anthropocene. The research initiative, within the framework of the GECANT project, aims at understanding how recent natural and anthropic changes have affected the geomorphological dynamics of Cantabrian watersheds (Northern Spain), which have experienced an intense human activity during the last centuries. For this purpose, a multi-file and multi-site approach has been used by integrating data from distinctive lakes and estuaries of a large range of environmental conditions comprising the whole Cantabrian region. A multidisciplinary strategy, including geomorphological analyses, instrumental climate records, limnological studies, and multi-proxy analysis of sediment cores (geochemistry, geochronology and palaeoecology), as well as socioeconomic data, has been used in order to disentangle the natural and human drivers and causes of environmental changes. The data obtained so far indicate an increase in sedimentation rates in lakes and estuaries since the middle of the 20th century. Conceivably, this research will lead to the improvement of our understanding of the synergistic effects of natural and human drivers at the basin scale whilst promoting an enhanced design of global change mitigation and adaptation policies.

An analysis and assessment of the effects of human activity on geomorphic processes related to denudation/sedimentation and landscape change, is presented. The analysis focuses on changes occurred during the last couple of centuries and is based on a variety of case studies from different regions as well as global assessments. Data compiled show that certain geomorphic processes are experiencing an important acceleration, in particular since the 1950’s. The acceleration seems to have a global character and suggests a “global geomorphic change” is taking place, largely due to anthropogenic landscape changes. Denudation directly caused through activities involving excavation, transport and accumulation of geological materials has increased by a factor of 30 between 1950 and 2015. Direct plus indirectly human-induced denudation (triggered by land surface alteration) is presently at least one order of magnitude greater than denudation due to purely natural processes. A general increase of sedimentation rates seems to have taken place since the end of the 19th century, and more intensely after the mid-20th century. This appears to respond mainly to land surface changes, in conjunction with climate change. Slope movements, which represent an important contribution to denudation, sediment generation and landscape evolution, show a clear intensification, in particular after mid-twentieth century. Frequency of disasters related to such movements (an indirect measure of process frequency) in specific regions, as well as continent and global levels, has grown considerably and the general increasing trend observed is not satisfactorily explained by climate change. It rather appears to reflect increasing landscape (land use and land cover) changes. A similar increase in the frequency of flood-related disasters has been recorded. The results obtained suggest that the extensive landscape changes described, related to the intensification of human activities affecting land surface, represent a geomorphic change of a global extent. This change shows an acceleration coinciding with the “great acceleration” proposed as one of the manifestations of the Anthropocene.

A discussion about the possible cause-effect links between some socioeconomic drivers and changes in geomorphic processes is presented. Different types of physical impacts, including geomorphic effects on land subsidence, denudation or frequency of geomorphic-related disasters, show global spatial distributions very similar to Gross Domestic Product (GDP) density, an indicator of the intensity of human pressure on the environment. The intensity of the indicated impacts has increased in recent times, particularly after mid-twentieth century. Data and estimates are presented showing that direct plus indirect “human erosion” is currently 1-2 orders of magnitude greater than purely natural one, and growing. Whereas GDP, as an indicator of per capita potential to modify the environment, has tripled in just over half a century, per capita human transfer of earth materials has increased tenfold. The frequency of disasters related to geomorphic processes has also been amplified about tenfold in less than a century. This increase is much greater than the one of other types of “natural” disasters. The changes observed in geomorphic processes appear to respond to land surface modification, to a great extent linked to urban and infrastructure development. The growing intensity of these stressors appears to have a global impact at least as great as that of climate, on the geomorphic changes described which seem to be one of the characteristics of the Anthropocene.

The effects of human activity on geomorphic processes, particularly those related to denudation/sedimentation, are investigated by reviewing case studies and global assessments covering the past few centuries. Evidence we have assembled from different parts of the world, as well as from the literature, show that certain geomorphic processes are experiencing an acceleration, especially since the mid-twentieth century. This suggests that a global geomorphic change is taking place, largely caused by anthropogenic landscape changes. Direct human-driven denudation (through activities involving excavation, transport, and accumulation of geological materials) has increased by a factor of 30 between 1950 and 2015, representing a ten-fold increase of per capita effect. Direct plus indirectly human-induced denudation (triggered by land surface alteration) is presently at least one order of magnitude greater than denudation due to purely natural processes. The activity of slope movements, which represent an important contribution to denudation, sediment generation and landscape evolution, also shows a clear intensification. Frequency of hazardous events and disasters related to slope movements (an indirect measure of process frequency) in specific regions, as well as at continental and global levels, has grown considerably, in particular after the mid-twentieth century. Intense rainstorm events are often related to slope movement occurrence, but the general increasing trend observed is not satisfactorily explained by climate. Sedimentation has augmented considerably in most regions and all kinds of sedimentation environments. Although the link between denudation and sedimentation is not direct and unequivocal, it is safe to assume that if sedimentation rates increase in different regions during a given period, denudation must have increased too, even though their magnitudes could be different. This augmentation, particularly marked from the second half of the last century onwards, appears to be determined mainly by land surface changes, in conjunction with climate change. The changes observed suggest: a) there is evidence at a global scale of a growing response of geomorphic systems to socio-economic drivers, being Gross Domestic Product density, a good indicator of the human potential to cause such impacts; b) Land use/cover changes enhance effects of climate change on global denudation/sedimentation and landslide/flood frequency, and appear to be a stronger controlling factor; c) Our findings point to the existence of a global geomorphic change. This manifestation of global change is especially evident since the ?great geomorphic acceleration? that began in the middle of the 20th century, and constitutes one of the characteristics of the proposed Anthropocene. This work was supported, at different stages, by projects: FEDER, AEI, CGL2017-82703-R (Ministerio de Ciencia e Investigacion, Spain) and PICT2011-1685; MTM2014-56235-C2-2215 (Ministerio de Ciencia, Tecnología e Innovacion, Argentina). We also thank Dr. Anthony R. Berger for critical review and writing assistance.

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.

Some advances in our methodological approach for visibility analysis (VA) and some relevant improvements of the software tool (MOYSES v4.0) are presented. Usually visibility studies and Visual Impact Assessments (VIA) are expressed as reports that are carried out only when design of projected structures is already completed. The proposal presented here provides methods and tools that can help to measure and incorporate visibility as a part of the engineering design process. Different queries can be formulated and alternative solutions can be compared during the design stage. The tools are interactive and designers can use them to visually optimise their final solutions.

We are very grateful to all the referees for their indispensable and unselfish work that greatly contributed to the improvement of the quality of the papers. The Department of the Environment and the Department of Science, Technology and University of the Aragón Government, as well as the Innovation Ministry of the Spanish Government (CGL2011-12465), provided financial support to organise the scientific meeting “Geomorphological Research in Spain” (Zaragoza, September, 2011). We thank the International Association of Geomorphologists (IAG), the Spanish Society of Geomorphology (SEG), and the Spanish Society of Quaternary Studies (AEQUA) for supporting the initiative. We are also very grateful to Dr. Cinta Marín for helping with the preparation of the bibliometric data and supplementary material presented in this guest editorial.

An analysis of changes experienced during the last century by certain indicators of the intensity of geomorphic processes in northern Spain is presented, in order to test a previously formulated hypothesis. The hypothesis, already tested in the Rio de la Plata Basin, is that there is a global geomorphic change which implies an acceleration of geomorphic processes in general, and that such acceleration is mainly due to the transformation of land surface by human activities, not to climate factors. Sedimentation rates obtained in eight estuaries in northern Spain, through Pb-210 and Cs-137 dating of sediment cores, show a general increase since the beginning of last century, and particularly after the 1950s. Similar increases in landslide frequency have been formerly observed in some areas of the same region. Trends of change in sedimentation rates have been compared with those of potential natural (rainfall) and human (indicators of the intensity of human activities that can contribute to land-surface transformation) drivers. There seems to be no relationship between rainfall and sedimentation rate trends but the magnitude and trends of several indicators of human activity are similar to those of the latter. Data on landslide frequency obtained in a small study area also show a possible relationship with land-use change and infrastructure development, but not with rainfall. The results described are coherent with the hypothesis and suggest that the process described could have a global character. If this is so, the worldwide observed increase in flood and landslide disasters might be a characteristic of the Anthropocene and due to human-induced geomorphic change, rather than climate change (also human-induced), as often assumed.

The different stages in the planning of wind power development and the pre-assessment of suitability of the territory in the province of Cantabria are described. The methodological approach used is explained. This approach included three main steps: a general environmental assessment of the whole province to identify potentially suitable areas on the basis of environmental criteria; a second, more detailed assessment of those areas using additional analyses and environmental criteria; an assessment of potential visual effects based on both measurable parameters and visual perception. Emphasis is placed on visual analysis and impact issues. Criteria and parameters used and technological simulation tools developed for the assessment of visual impacts and mitigation measures are discussed and results obtained shown. A description is also presented of political and social reactions to wind energy development plans. The results of the study indicate that the 1400 MW planned would be possible without important environmental effects, if wind farms are restricted to the 2% of the province identified as potentially suitable. Also, that simulation tools developed make it possible to rapidly and reliably represent and assess potential visual modifications. These tools can thus be used not only for expert’s assessment, but also as a means to facilitate social participation in the planning process.

The assessment of geoheritage is a crucial task for the establishment of ranks according to their value, an important step for the elaboration of catalogues and the implementation of protection and use programmes. One important problem that permeates the different stages of geoheritage assessment is subjectivity in the selection and application of criteria. Evaluation methods frequently used are based on the assignment of values through the expert’s judgement (direct methods). In the last few decades, parametric methods, based on the measurement of specific features of geomorphosites have been increasingly applied. This type of procedure allows different operators to obtain similar results if certain criteria are accepted, but it requires more time and effort. A parametric method is proposed here based on three sets of criteria: intrinsic quality, potential for use and protection needs. The method has been tested on a series of coastal geomorphosites. Specific criteria, parameters to express them and value ranks are proposed. A statistical approach has been applied to the criteria to identify the most significant ones and their relative weights. The analysis enabled reduction of the number of criteria, eliminating redundancies. The new set of criteria was applied to assess the value of geomorphosites located in the north of Spain. The classification was compared with the ones obtained by both the parametric method using a larger number of parameters and a direct evaluation applied to the same sites. Results show a quite good coincidence. It is concluded that this approach makes it possible to obtain reliable classifications of geomorphosites based on clearly defined criteria and replicable procedures, but with a much lower effort, using a limited number of criteria.

Multiple sinkhole susceptibility models have been generated in three study areas of the Ebro Valley evaporite karst (NE Spain) applying different methods (nearest neighbour distance, sinkhole density, heuristic scoring system and probabilistic analysis) for each sinkhole type separately (cover collapse sinkholes, cover and bedrock collapse sinkholes and cover and bedrock sagging sinkholes). The quantitative and independent evaluation of the predictive capability of the models reveals that: (1) The most reliable susceptibility models are those derived from the nearest neighbour distance and sinkhole density. These models can be generated in a simple and rapid way from detailed geomorphological maps. (2) The reliability of the nearest neighbour distance and density models is conditioned by the degree of clustering of the sinkholes. Consequently, the karst areas in which sinkholes show a higher clustering are a priori more favourable for predicting new occurrences. (3) The predictive capability of the best models obtained in this research is significantly higher (12.5–82.5%) than that of the heuristic sinkhole susceptibility model incorporated into the General Urban Plan for the municipality of Zaragoza. Although the probabilistic approach provides lower quality results than the methods based on sinkhole proximity and density, it helps to identify the most significant factors and select the most effective mitigation strategies and may be applied to model susceptibility in different future scenarios.

A detailed sinkhole map has been produced in a stretch of the Ebro Valley (40.8 km2) including the western sector of Zaragoza city (NE Spain). During the last few decades, around 70% of the original sinkhole area has been filled with anthropogenic sediments causing the disappearance of 137 ha of wetlands. The interstratal karstification of salts (halite and glauberite) and a WNW–ESE-trending joint set have played a major control in the development of sinkholes. Three morphometric types of sinkholes have been differentiated, each attributed to a specific subsidence mechanism inferred from the paleosinkholes exposed in the surrounding of Zaragoza city; sagging of bedrock and cover, collapse of bedrock and cover, and collapse of cover material related to the downward migration of particles through dissolutional conduits. Each type of sinkhole is characterised by a distinctive behaviour in terms of controlling factors, spatio-temporal distribution and kinematics, and consequently the proposed differentiation may have a practical utility. The vast majority of the subsidence damage identified in the area occurs within the boundaries of pre-existing sinkholes identifiable in old aerial photographs and topographical maps. This fact demonstrates that the application of preventive planning strategies based on detailed geomorphological maps would have allowed avoidance of most of the large financial losses caused by subsidence in the area, of the order of hundreds of thousands of euros per year.

A method for quantitatively assessing sinkhole susceptibility (spatial probability) and hazard (spatio-temporal probability) has been developed and independently tested in a 50 km2 sector of the Ebro Valley evaporite karst. Three genetic types of sinkholes have been mapped in the floodplain and a terrace surface: 947 small cover-collapse sinkholes (type 1, terrace), large collapse sinkholes (type 2, floodplain) and large subsidence depressions (type 3, floodplain). The type 1 sinkhole inventory includes two temporal populations: 447 sinkholes formed before 24 November 2005, and 500 between that date and 2 November 2006. Sinkhole susceptibility models have been elaborated analysing the statistical relationships between the sinkholes of the 2005 inventory and a set of potential conditioning factors. The independent evaluation (validation) of the susceptibility models by means of several strategies (random, sequentially excluded, and temporal) has allowed us to select the most significant variables for each sinkhole type and assess quantitatively the quality of models; which are reasonable for the three sinkhole types. Validation has also provided information on the contribution of specific variables and the effect of changing their accuracy to the prediction capability of models. Susceptibility models for type 3 sinkholes have been validated satisfactorily with the 2006 sinkhole inventory (temporal validation). The best susceptibility model has been transformed into a hazard map considering the frequency of sinkholes that occurred in each susceptibility class between 2005 and 2006, as well as their average size. The susceptibility and hazard models obtained could be used as an objective basis for the application of mitigation measures, either of preventive or corrective nature. Copyright © 2008 John Wiley & Sons, Ltd.

A preliminary sinkhole susceptibility analysis has been carried out in a stretch 50 km 2 in area of the Ebro valley alluvial evaporite karst (NE Spain). A spatial database consisting of a sinkhole layer and 27 thematic layers related to causal factors was constructed and implemented in a GIS. Three types of sinkholes were differentiated on the basis of their markedly different morphometry and geomorphic distribution: large subsidence depressions (24), large collapse sinkholes (23), and small cover-collapse sinkholes (447). The susceptibility models were produced analysing the statistical relationships between the mapped sinkholes and a set of conditioning factors using the Favourability Functions approach. The statistical analyses indicate that the best models are obtained with 6 conditioning factors out of the 27 available ones and that different factors and processes are involved in the generation of each type of sinkhole. The validation of two models by means of a random-split strategy shows that reasonably good predictions on the spatial distribution of future dolines may be produced with this approach; around 75% of the sinkholes of the validation sample occur on the 10% of the pixels with the highest susceptibility and about 45% of the area can be considered as safe.

A quantitative procedure for mapping landslide risk is developed from considerations of hazard, vulnerability and valuation of exposed elements. The approach based on former work by the authors, is applied in the Bajo Deba area (northern Spain) where a detailed study of landslide occurrence and damage in the recent past (last 50 years) was carried out. Analyses and mapping are implemented in a Geographic Information System (GIS). The method is based on a susceptibility model developed previously from statistical relationships between past landslides and terrain parameters related to instability. Extrapolations based on past landslide behaviour were used to calculate failure frequency for the next 50 years. A detailed inventory of direct damage due to landslides during the study period was carried out and the main elements at risk in the area identified and mapped. Past direct (monetary) losses per type of element were estimated and expressed as an average ‘specific loss’ for events of a given magnitude (corresponding to a specified scenario). Vulnerability was assessed by comparing losses with the actual value of the elements affected and expressed as a fraction of that value (0–1). From hazard, vulnerability and monetary value, risk was computed for each element considered. Direct risk maps (€/pixel/year) were obtained and indirect losses from the disruption of economic activities due to landslides assessed. The final result is a risk map and table combining all losses per pixel for a 50-year period. Total monetary value at risk for the Bajo Deba area in the next 50 years is about 2.4 × 106 Euros.

Three types of sinkhole have been mapped in a 50 km2 stretch of the Ebro River valley downstream of Zaragoza: large collapse sinkholes, large shallow subsidence depressions and small cover-collapse sinkholes. The sinkholes relate to the karstification of evaporitic bedrock that wedges out abruptly downstream, giving way to a shale substratum. Twenty-three collapse sinkholes, up to 50 m in diameter by 6 m deep, and commonly hosting saline ponds, have been identified in the floodplain. They have been attributed to the upward stoping of dissolutional cavities formed within the evaporitic bedrock by rising groundwater flows. Twenty-four large shallow subsidence depressions were mapped in the floodplain. These may reach 850 m in length and were formed by structurally controlled interstratal karstification of soluble beds (halite or glauberite? and gypsum) by rising groundwater flow and the progressive settlement of the overlying bedrock and overburden sediments. A total of 447 small cover-collapse, or dropout, sinkholes have been recognized in a perched alluvial level along the southern margin of the valley. These sinkholes result from the upward propagation of voids through the alluvial mantle caused by the downward migration of detrital sediments into dissolutional voids. The majority of these sinkholes, commonly 1·5–2 m in diameter, are induced by human activities. Over the karstic bedrock, there is a significant increase in sinkhole density downstream. This is interpreted as being a result of the evaporitic bedrock wedging out and the convergence of the groundwater flow lines in the karstic aquifer. The collapse sinkholes in this area, locally with a probability of occurrence higher than 140 sinkholes/km2/year, cause substantial damage to the linear infrastructures, buildings and agriculture, and they might eventually cause the loss of human lives. Copyright © 2006 John Wiley & Sons, Ltd.

An analysis is presented on the contribution of urban and infrastructure development, mining and quarrying to direct and indirect modifications of landforms and transfer of earth materials. The analysis has been carried out in four study areas in Spain and Argentina and is based on data collection on the amounts of materials excavated for those activities and related sediment production. Results obtained show that human activity is presently the main contributor to landform modification and earth material transport in the study areas; mobilisation rates due to construction and mining seem to be 2–4 orders of magnitude greater than natural denudation rates. The ‘human geomorphic footprint”, expressed in terms of new landform creation rate and mobilisation rate is calculated for the study areas. Extrapolation to the global level is made on the basis of data obtained and mineral production data. Comparison with data on erosion rates and world sediment transport indicates that the latter is an order of magnitude less than construction plus mining mobilisation. It is suggested that geomorphic and related changes observed may represent manifestations of a global geomorphic change.

A procedure for landslide risk assessment is presented. The underlying hypothesis is that statistical relationships between past landslide occurrences and conditioning variables can be used to develop landslide susceptibility, hazard and risk models. The latter require also data on past damages. Landslides occurred during the last 50 years and subsequent damages were analysed. Landslide susceptibility models were obtained by means of Spatial Data Analysis techniques and independently validated. Scenarios defined on the basis of past landslide frequency and magnitude were used to transform susceptibility into quantitative hazard models. To assess vulnerability, a detailed inventory of exposed elements (infrastructures, buildings, land resources) was carried out. Vulnerability values (0–1) were obtained by comparing damages experienced in the past by each type of element with its actual value. Quantitative risk models, with a monetary meaning, were obtained for each element by integrating landslide hazard and vulnerability models. Landslide risk models showing the expected losses for the next 50 years were thus obtained for the different scenarios. Risk values obtained are not precise predictions of future losses but rather a means to identify areas where damages are likely to be greater and require priority for mitigation actions.

The temporal occurrence of slope movements, their contribution to relief evolution and human influence on those processes in two study areas of northern Spain are presented. The work is based on temporal analyses covering 100 ka in one study area and 43 years in the other. Temporal analysis has been the basis for quantitatively assessing the magnitude of human influence and developing landslide susceptibility and hazard models with known, independently-tested prediction capability. The results obtained in one study area show a relationship between landsliding periods and increasing precipitation during upper Pleistocene and Holocene. Significant increases of landslide frequency and mobilisation rate were also found around 5500 and 200 years ago. Those moments coincide with two periods of intensified human presence and activities: Neolithic and industrial revolutions. The increase observed represents about one order of magnitude from pre-Neolithic to present. A similar increase has been found between 1954 and 1997 in the other study area. The latter increase shows no relationship with changes in climate parameters or seismic activity. A fairly good correlation has been found between landslide frequency and socioeconomic indicators of human activity. Sedimentation rates in two neighbouring estuaries were determined and significant increases, particularly in the second part of last century, were also found. Evidence obtained suggest that the increases observed in the frequency of slope instability events (and therefore hazard), denudation and sedimentation rates are due to a greater extent to indirect geomorphologic changes caused by human action rather than climate change. Detailed analysis of landslide frequency during that 43-year period has also been used to produce and validate landslide susceptibility models and obtain landslide hazard maps with known prediction accuracy. Validation tests were carried out comparing susceptibility maps based on landslides that have occurred in the past with the ones occurring in several, later periods. Prediction capability of models could thus be determined. Validation of susceptibility maps using data derived from the temporal analysis of landslides was used to obtain hazard maps expressed as probability of new ruptures in a given time period, on the basis of past trends in terrain behaviour. Possible impacts of a growing influence of human activities on the terrain have been incorporated into the assessment of future hazards by considering different scenarios.

A methodological proposal for the assessment of impacts due to linear infrastructures such as motorways, railways, etc. is presented. The approach proposed includes a series of specific issues to be addressed for each geomorphological feature analysed - both 'static' and 'dynamic'- as well as a series of steps to be followed in the process. Geomorphic characteristics potentially affected were initially identified on the basis of a conceptual activities/impacts model that helps to single out geomorphic impacts related to environmental concerns for the area. The following issues were addressed for each individual impact: nature of potential effects; indicators that can be used to measure impacts; criteria of 'geomorphologic performance'; procedure for measurement/prediction of changes; translation of geomorphologic impacts into significant terms from the viewpoint of human concerns; possible mitigation and/or compensation measures. The procedure has been applied to a case study corresponding to a new motorway in the Basque Country, northern Spain. Geomorphological impacts considered in this analysis included: (1) consumable resources; (2) sites of geomorphological interest; (3) land units with high potential for use, high productivity or value for conservation; (4) visual landscape; (5) slope instability processes. The procedure has been designed for implementation in a Geographic Information System (GIS) environment. Details are given on the application of the method to each individual impact analysed and results are presented in both numerical and map form. Impacts assessed were initially expressed by means of heterogeneous magnitudes, depending on the geomorphological feature considered. Those geomorphological impacts were then translated into significant terms and homogeneous magnitudes. Integration was carried out on the basis of impact values thus obtained. Final integrated results were also expressed in numerical and map form. The method proposed enables comparison of alternatives as well as 'prediction' and assessment of impacts in terms directly related to geomorphic characteristics. It also facilitates the expression of those impacts in terms that allow integration with other types of environmental impacts. © 2004 Elsevier B.V. All rights reserved.

A quantitative methodology for landslide susceptibility zonationis described and its application to a study area in the lower part of the Deba Valley (Guipuzcoa,Spain) presented. Susceptibility models were obtained on the basis of statisticalrelationships between known mass movements and conditioning factors. A landslide rupturehypothesis was set and a digital database consisting of seventeen causal factors layers constructed.The modelling procedure was implemented utilising a GIS. The susceptibility analysis methodis based on the Favourability Functions approach, and two different mathematicalframeworks: probability theory and Zadehis fuzzy set theory. Several landslidesusceptibility models were produced and validated using different sets of independent landslide data.The predictive capability of models was determined.

This contribution explores a strategy for landslide hazard zonation in which layers of spatial data are used to represent typical settings in which given dynamic types of landslides are likely to occur. The concepts of assessment and prediction are defined to focus on the representation of future hazardous events and in particular on the myths that often provide obstacles in the application of quantitative methods. The prediction-rate curves for different applications describe the support provided by the different data layers in experiments in which the typical setting of hazardous events is approximated by statistically integrating the spatial information.

A procedure for validating landslide susceptibility maps wasapplied in a study area in northern Spain and the results obtained compared. Validationwas used to carry out sensitivity analysis for individual variables and combinationsof variables. The validity of different map-making methods was tested, as well as theutility of different types of Favourability Functions. The results obtained show thatvalidation is essential to determine the predictive value of susceptibility maps. Italso helps to better select the most suitable function and significant variables, thus improving the efficiency of the mapping process. Validation based on a temporal strategy makes it possible to derive hazard maps from susceptibility maps.

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.

Se presenta un proyecto de medida de la calidad ambiental de una region. El metodo propuesto se basa en la identificacion de caracteristicas que sean cuantificables mediante indices cuantitativos. A traves de los distintos ejemplos de valores de los indicadores en los paises estudiados, se estudia la posibilidad de correlacionar los indicadores propios de la salud con los indices de la calidad ambiental.

The temporal occurrence of landslides in an area of the Cantabrian Range during the last 120,000 years is analyzed. An initial relative chronology was established on the basis of aging degree and spatial relationships between landslides and glacial and fluvial features. Ten landslide classes were thus identified and their chronological limits defined on the basis of 19 14C age determinations on fluvial and glacial deposits (including eight new ones). The chronology was tested with 14C dates obtained on landslide deposits, 10 from previous work and nine new ones. The chronological classes identified were compared with existing climate models for the region; the type and spatial distribution of landslides in each class were also analyzed. The approach made it possible to identify periods during which landslides were triggered mainly by channel incision, seismic activity and rainfall increase. Human activity played a significant role after 5000 BP and especially in the last few centuries. Mobilization of materials by slope movements has increased in the region by a factor of 10, compared to pre-Neolithic rates.

This paper describes a survey of southern California municipal planners to determine thier degree of emphasis given to coastal hazards within their jurisdictions. With growing property losses associated with the coastal zones of southern California, the study was undertaken to assess the role of scientific information and hazard responses in coastal planning for land use decisions. The findings show that planners lack knowledge of their coastal zones and view the coastal zones as just one element in the overall planning process. Their emphasis on day‐to‐day development permitting overshadows a proactive stance on strategic planning for coastal hazards.

A methodological approach is proposed for the incorporation of geomorphological features into environmental impact assessments. A series of quantitative indicators and indices are proposed, so that impacts on both consumable and non-consumable geomorphological resources can be objectively determined. Impact can thus be expressed by means of magnitudes with specific dimensions, or at least as fractions of a maximum theoretical value. Procedures for the integration of individual indices into general impact assessments are also proposed.

A reconstruction of Holocene climate changes in the Cantabrian region, based on pollen records and on complementary sedimentological, geomorphological, archaeological and oxygen isotope data is presented. The climate model thus proposed has been tested obtaining new sediment records and dating sixteen additional samples. The distribution and relative chronology of slope movements in a study area are presented. Eleven new dates have been obtained for landslide and flow deposits and a correlation between occurrence of mass movements and climate changes is proposed. The volumes affected by these movements in different periods have been calculated and rates have been obtained. Estimates of denudation rates in the study area during the Quaternary and in the Holocene are also presented and compared with the former.

After a review of some analytical and conceptual models of slope evolution with the intervention of mass movements, a proposal is made of a series of indicators for the quantitative description of landscape evolution in relation to mass movements. The ratio between landslide mobilisation rate and downwearing rate is proposed as a quantitative measure of the significance of mass movements in landscape evolution. A subdivision of European regions with respect to their susceptibility to landsliding as a process of landscape evolution is proposed. The role of landsliding for the evolution of landscape in some regions is described. The data presented show that landsliding may in some cases be the main contributor to landscape change.

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.

The problems involved in environmental assessment of land‐use plans are discussed. A methodology is proposed for incorporating into the assessment of a plan the modifications that the physical environment would experience as a result of the plan's implementation. Thus, EIA can be integrated into the planning process. Impact assessment and comparison between alternative plans can be made using quantitative and qualitative indicators, some of which are proposed. Several case studies in northern Spain are used as the basis for the suggestions made.

The extent of degraded estuarine and wetland zones on the north coast of Spain is discussed. A method for the analysis and diagnosis of such zones is proposed. The method is based on the identification and mapping of homogeneous environmental units and the definition of indicators for the assessment of these units in terms of attributes relevant for restoration and management. The specification of a set of criteria enables the diagnosis maps thus obtained to be transformed into maps with proposals for management actions, for which specific designs are proposed. The cost of the actions proposed is also estimated. The results obtained from the analysis in three small estuaries are extrapolated to determine the possible extent of different rehabilitation activities and to estimate the cost of recovery plans for the whole coastal sector analysed.

A method for the identification, mapping and evaluation of integrated environmental units is described. This method is applied to the assessment and zoning of a biosphere reserve, in order to establish guidelines for the distribution of conservation and management actions. The method, based on the definition of units according to observable features, enables the diagnosis of qualities of interest for planning and management, with results that can be reproduced by different operators, if certain initial criteria are accepted. Using these criteria, initial descriptive maps can be transformed into prescriptive maps which provide the basis for management decisions. The nature and distribution of the units present in the area is shown. The allocation of land-use activities obtained using the criteria indicated above provides the basis for economic assessment of development plans. A series of conservation and development actions are proposed for the reserve.

The results of 64 new KAr age determinations, together with 32 previously published ages, show that after a period of erosion of the basal complex, Miocene volcanic activity started around 20 Ma in Fuerteventura and 15 Ma in Lanzarote, forming a tabular succession of basaltic lavas and pyroclastics with a few salic dykes and plugs. This series includes five separate volcanic edifices, each one with its own eruptive history. In Fuerteventura, several Miocene eruptive cycles have been identified: in the central edifice one around 20–17 Ma, followed by two others centred around 15 and 13 Ma; in the southern edifice the maximum of activity took place around 16–14 Ma, whereas in the northern one the main activity occurred between 14 and 12 Ma. In Lanzarote a first cycle of activity took place in the southern edifice between 15.5 and 14.1 Ma, followed by another between 13.6 and 12.3 Ma. In the northern edifice three pulses occurred: 10.2–8.3, 6.6–5.3 and 3.9–3.8 Ma. An important temporal gap, greater in Fuerteventura than in Lanzarote, separates Series I from the Plio-Quaternary Series II, III and IV, formed by multi-vent basaltic emissions. In Fuerteventura the following eruptive cycles have been identified: 5, 2.9–2.4, 1.8–1.7, 0.8–0.4 and

An analysis of geomorphic system's response to change in human and natural drivers in some areas within the Rio de la Plata basin is presented. The aim is to determine whether an acceleration of geomorphic processes has taken place in recent years and, if so, to what extent it is due to natural (climate) or human (land-use) drivers. Study areas of different size, socio-economic and geomorphic conditions have been selected: the Rio de la Plata estuary and three sub-basins within its watershed. Sediment cores were extracted and dated ((210)Pb) to determine sedimentation rates since the end of the 19th century. Rates were compared with time series on rainfall as well as human drivers such as population, GDP, livestock load, crop area, energy consumption or cement consumption, all of them related to human capacity to disturb land surface. Data on river discharge were also gathered. Results obtained indicate that sedimentation rates during the last century have remained essentially constant in a remote Andean basin, whereas they show important increases in the other two, particularly one located by the Sao Paulo metropolitan area. Rates in the estuary are somewhere in between. It appears that there is an intensification of denudation/sedimentation processes within the basin. Rainfall remained stable or varied very slightly during the period analysed and does not seem to explain increases of sedimentation rates observed. Human drivers, particularly those more directly related to capacity to disturb land surface (GDP, energy or cement consumption) show variations that suggest human forcing is a more likely explanation for the observed change in geomorphic processes. It appears that a marked increase in denudation, of a "technological" nature, is taking place in this basin and leading to an acceleration of sediment supply. This is coherent with similar increases observed in other regions.

This contribution presents a quantitative procedure for landslide risk analysis and zoning considering hazard, exposure (or value of elements at risk), and vulnerability. The method provides the means to obtain landslide risk models (expressing expected damage due to landslides on material elements and economic activities in monetary terms, according to different scenarios and periods) useful to identify areas where mitigation efforts will be most cost effective. It allows identifying priority areas for the implementation of actions to reduce vulnerability (elements) or hazard (processes). The procedure proposed can also be used as a preventive tool, through its application to strategic environmental impact analysis (SEIA) of land-use plans. The underlying hypothesis is that reliable predictions about hazard and risk can be made using models based on a detailed analysis of past landslide occurrences in connection with conditioning factors and data on past damage. The results show that the approach proposed and the hypothesis formulated are essentially correct, providing estimates of the order of magnitude of expected losses for a given time period. Uncertainties, strengths, and shortcomings of the procedure and results obtained are discussed and potential lines of research to improve the models are indicated. Finally, comments and suggestions are provided to generalize this type of analysis.

A series of case studies is presented showing how units defined on the basis of geological-geomorphological criteria can be used for summarizing information about a great variety of environmental parameters and for the assessment of many qualities of interest for planning and decision-making. These qualities refer to both geological and non-geological aspects. The utilization of geoenvironmental units for the establishment of land-use regulations, for planning management actions and for evaluation of some economic aspects is also illustrated.

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.

O objetivo principal do projeto RELESA/ELANEM foi elaborar uma nova proposta metodológica para a obtenção de índices e indicadores quantitativos de avaliação da qualidade ambiental que seja aplicável a diferentes regiões e ofereça a possibilidade de obter resultados quantitativamente comparáveis. A proposta remete em testar um procedimento capaz de medir a qualidade ambiental e possíveis relações estabelecidas com as pressões derivadas de ações humanas, assim como o nível de resposta da sociedade para mudanças na condição do ambiente, objetivando a sustentabilidade dos recursos naturais. A espacialização das informações dá-se através da identificação, mapeamento e análise de Unidades Ambientais Integradas, delimitadas com atributos distintos, isto é, de acordo com as formas de uso e ocupação de cada ambiente. É neste contexto que a componente geomorfológica assume importância fundamental na delimitação destas unidades.

New age determinations from Tenerife, together with those previously published (93 in all), provide a fairly comprehensive picture of the volcanic evolution of the island. The oldest volcanic series, with ages starting in the late Miocene, are formed mainly by basalts with some trachytes and phonolites which appear in Anaga, Teno and Roque del Conde massifs. In Anaga (NE), three volcanic cycles occurred: one older than 6.5 Ma, a second one between 6.5 and 4.5 Ma, with a possible gap between 5.4 and 4.8 Ma. and a late cycle around 3.6 Ma. In Teno (NW), after some undated units. the activity took place between 6.7 and 4.5 Ma, with two main series separated by a possible pause between 6.2 and 5.6 Ma. In the zone of Roque del Conde (S),the ages are scattered between 11.6 and 3.5 Ma. Between 3.3 and 1.9 Ma, the whole island underwent a period of volcanic quiescence and erosion. The large Caaadas volcano, made up of basalts, trachytes and phonolites, was built essentiaiiy between 1.9 and 0.2 Ma. To the NE of this'central volcano, linking it with Anaga, is a chain of basaltic emission centers, with a peak of activity around 0.8 Ma. The Cañadas Caldera had several collapse phases, associated with large ignimbrite emissions. There were, at least, an older phase more than 1 Ma old, on the western part of the volcano, and a younger one, less than 0.6 Ma old, in the eastern side. The two large "valleys" of Guimar and la Orotava were formed by large landslides less than 0.8 Ma ago, and probably before 0.6 Ma ago. The present Cañadas caldera was formed by another landslide, less than 0.2 Ma ago. This caldera was later filled by the huge Teide volcano, which has been active even in historic times. During the same period a series of small volcanoes erupted at scattered locations throughout the island. The average eruptive rate in Tenerife was 0.3 km3/ka, with relatively small variations for the different eruptive periods. This island and La Gomera represent a model of growth by discontinuous pulses of volcanic activity, separated by gaps often coinciding with episodes of destruction of the edifices and sometimes extended for several million years. The neighbouring Gran Canaria, on the other hand, had an initial, rapid "shield-building phase" during which more than 90% of the island was built, and a series of smaiier pulses at a much later period. A comparison between these three central islands indicates that the previously postulated westward displacement in time of a gap in the volcanic activity is valid only as a first approximation. Several gaps are present on each island, overlapping in time and not clearly supporting either of the models proposed to explain the evolution of the Canaries.

A geochronological study of the Island of La Gomera (Canaries) has been carried out by the K-Ar method. The 26 new ages obtained, together with the 17 previous determinations, show that above the main unconformity of the island, separating the « basal complex » from the later volcanic series, there is a unit of « lower old basalts » more than 10 m.y. old. Polymictic volcanic breccias were emplaced between 10 and 9 m.y. ago. The « upper old basalts » above them were formed between 9 and 6 m.y. ago, with a peak of activity around 7 m.y. After a period of erosion (6-5 m.y.), a thick series of « young basalts » associated with trachytic and phonolitic domes and flows, were rapidly emplaced between 4.5-4 m.y. ago. Finally, local basaltic activity took place 2.8 m.y. ago. The age of the basal complex is not well known, although three ages (14.6, 15.5 and 19.3 m.y.) have been obtained for some alkaline intrusives which seem to represent the youngest events in the complex.

The Santander Bay area on the north coast of Spain has been selected for a study comparing its environmental geology features with the resource capability, and present land and water use. The environmental geologic map of the Santander Bay area consists of 53 environmental units grouped into six major environmental systems.Systems are process-defined, whereasunits are defined according to active processes, landform, physical properties of the materials, biologic assemblages, and man's influence. In each case the feature considered to be of first-order environmental significance is used to define the unit, but all other features are included in its description. With the information available at present, only qualitative characterization of the units has been possible. Capability or carrying capacity of the environmental units has been evaluated and mapped in relation to 21 types of human activity, derived from different land-use practices. The evaluation is by a matrix. Capability of the units is a consequence of their properties, but no capability judgments are implied in the definition of the units. It is convenient to distinguish between activities which are harmful for the environment if carried out on a certain unit and activities for which certain units might be unsuitable or hazardous to man. Some of the present land-use practices are in conflict with the natural capability of the units. Particularly threatened is the bay-estuarine system, especially the marshes and intertidal areas. From the data presented, information pertinent to land-use planning can be obtained, especially about units which are adequate for waste disposal, units which should be preserved, and units suitable for construction. More precise, quantitative characterization of the environmental units should be undertaken immediately. This would make possible the formulation of land-use planning policies in accordance with the natural capability of the environment. Planning according to capability of the units will allow maximum use of the natural resources of the area with minimum environmental damage.

A case of poor development of vegetation on roadcuts along a motorway — with a decrease in the aesthetic quality of the roadside and an increase in road maintenance costs — is presented. Field observations as well as pH and sulphur content determinations carried out on bedrocks and weathering materials suggest that the death of the vegetation is due to the production of sulphuric acid upon the weathering of iron sulphides present in the rock. Possible corrective measures are proposed.