Slope units-based flow susceptibility model: using validation tests to select controlling factors

A susceptibility map for an area, which is representative in terms of both geologic setting and slope instability phenomena of large sectors of the Sicilian Apennines, was produced using slope units and a multiparametric univariate model. The study area, extending for approximately 90 km2, was partitioned into 774 slope units, whose expected landslide occurrence was estimated by averaging seven susceptibility values, determined for the selected controlling factors: lithology, mean slope gradient, stream power index at the foot, mean topographic wetness index and profile curvature, slope unit length, and altitude range. Each of the recognized 490 landslides was represented by its centroid po…

La Franosità diffusa dell'1 Ottobre 2009 nel territorio ionico-peloritano della Provincia di Messina: stato delle indagini e prime considerazioni sulle dinamiche geomorfiche attivate.

A seguito di un evento estremo di pioggia verificatosi il 1 ottobre 2009 in un settore circoscritto del versante ionico della Provincia di Messina, si sono sviluppati numerosi eventi franosi classificabili per la maggior parte come colate di fango e detrito a rapida evoluzione (debris-mud flows). Dai primi sopralluoghi effettuati, in assenza ancora di un censimento sistematico, si sono riconosciuti eventi in numero di oltre 500, che hanno interessato sia nei versanti interni dei bacini idrografici che sversano nello Ionio, sia sui rilievi direttamente prospicienti la costa. L’elevato numero di eventi occorsi ha consentito di dettagliare dal punto di vista morfologico i fenomeni avvenuti e d…

UTILIZACIÓN DE TÉCNICAS DE FOTO-RECONSTRUCCIÓN 3D AUTOMATIZADA EN GEOMORFOLOGÍA: EJEMPLOS PARA DIFERENTES MORFOLOGÍAS Y ESCALAS

Three-dimensional photo-reconstruction methods based on Structure from Motion (SfM) and MultiView-Stereo techniques (MVS) are tested for measuring, monitoring and quantifying three different geomorphological features: i) the Corral del Veleta rock glacier and ii) five small gully headcuts in Spain and iii) Calanchi type badland in Italy. Results about the accuracy, usefulness and applicability of these techniques are presented here. The results of these analyses showed centimeter-level accuracies with average distances to the benchmark models ranging from 0.009 m to 0.42 m.

UTILIZZO DEL SISTEMA GOOGLE EARTH PER LA DEFINIZIONE DI UN MODELLO DI SUSCETTIBILITÀ DA FRANA: UN TEST IN SICILIA CENTRALE

Exploiting Google EarthTM to assess a landslide susceptibility model: a test in central Sicily. A landslide susceptibility multivariate model, based on the conditional analysis approach, has been derived in the Tumarrano river basin (about 78 km2), by intersecting a GIS grid layer, expressing some selected geo-environmental conditions (outcropping lithology, steepness, plan curvature and topographic wetness index), and a landslide vector archive, produced by a Google EarthTM aided remote survey. The analysis of the Google EarthTM images dated at 2006, allowed to recognize 733 landslides (30 rotational slides and 703 flows), almost exclusively affecting clay and sandy clay rocks. Validation …

MULTIVARIATE ANALYSIS OF GULLY-EROSION PROCESS: SUSCEPTIBILITY ASSESSMENT AND TEMPORAL VALIDATION IN A WATERSHED OF NORTH-CENTRAL SICILY, ITALY

CART-based gully types classification: a case study in Sicily (Italy)

Gulling is a complex process depending on several factors and involving a wide range of sub-processes. Different types of gullies were distinguished and described in literature. Their contribution to soil erosion changes in relation with the typology and their presence is influenced by different controlling factors. Mapping and classifying gullies is crucial for monitoring soil erosion. So far, no systematic definition of morphological characteristics of the different types of gullies and of their controlling factors has been made. The present work aims to suggest an innovative approach to automatically classify gullies by integrating remote sensing, GIS and a classification algorithm. The …

Monitoring of erosion on two calanchi fronts – Northern Sicily (Italy)

In the present research, two neighbouring calanchi fronts have been monitored by means of repeated readings on erosion pins, that were carried out between November 2006 and October 2008. During the monitoring period, a gauge station has been recording rainfalls, allowing us to compute the Rainfall-Runoff Erosivity Factor of the USLE model. The research highlighted: i) a general correspondence between rainfalls temporal trends and surface variation rhythms; ii) alternating erosion and deposition phases result in a retreat of the “calanchi” fronts.

Sicilia: bacini idrografici, corsi d'acqua e laghi

Analisi geostatistica dei processi erosivi nel bacino del Fiume Naro (Sicilia centro-meridionale)

GIS-analysis of gully erosion susceptibility: a key study in north-central Sicily,Italy

Fattori di controllo sullo sviluppo delle forme calanchive in NW Sicilia, Italia Meridionale

A comparison of statistical methods and multi-criteria decision making to map flood hazard susceptibility in Northern Iran

In north of Iran, flood is one of the most important natural hazards that annually inflict great economic damages on humankind infrastructures and natural ecosystems. The Kiasar watershed is known as one of the critical areas in north of Iran, due to numerous floods and waste of water and soil resources, as well as related economic and ecological losses. However, a comprehensive and systematic research to identify flood-prone areas, which may help to establish management and conservation measures, has not been carried out yet. Therefore, this study tested four methods: evidential belief function (EBF), frequency ratio (FR), Technique for Order Preference by Similarity To ideal Solution (TOP…

Geomorphological study of “calanchi” slopes of the Scillato basin (northern Sicily)

Validation of multivariated landslide hazard model in the Guddemi river basin (Northern Sicily,Iitaly)

Landform classification: a high-performing mapping unit partitioning tool for landslide susceptibility assessment—a test in the Imera River basin (northern Sicily, Italy)

In landslide susceptibility studies, the type of mapping unit adopted affects the obtained models and maps in terms of accuracy, robustness, spatial resolution and geomorphological adequacy. To evaluate the optimal selection of these units, a test has been carried out in an important catchment of northern Sicily (the Imera River basin), where the spatial relationships between a set of predictors and an inventory of 1608 rotational/translational landslides were analysed using the multivariate adaptive regression splines (MARS) method. In particular, landslide susceptibility models were prepared and compared by adopting four different types of mapping units: the largely adopted grid cells (PX…

Ruolo dei fenomeni di deformazione gravitativa profonda di versante nell'evoluzione geomorfologica di grandi rilievi carbonatici della Sicilia occidentale

Cloud-based interactive susceptibility modeling of gully erosion in Google Earth Engine

The gully erosion susceptibility literature is largely dominated by contributions focused on model comparison. This has led to prioritize certain aspects and leave others underdeveloped as compared to other natural hazard applications. For instance, in gully erosion data-driven modeling most studies use different platforms when it comes to data management, modeling and conversion into predictive maps. This in turn has limited the scope to catchment-scales. In this manuscript, we opt to propose a tool where the whole modeling procedure is unified within the same cloud computing system, allowing one to get rid of potential errors caused by input/output operations but also to extend the study …

Characterization of the soil properties in agricultural areas affected by shallow landslides: application in Messina area (Sicily).

The determination of soil properties is considerable challenge when it is aimed to evaluate the spatial distribution of one or more parameters across significant surfaces. In fact, terrain sampling and field data are punctual measurement; therefore, quantitative models are needed to predict the spatial distribution of soil attributes. The spatialization of field and laboratory data is a very important information in landslide studies. Raster layers displaying soil properties can be used both for statistical models and for the parameterization of physically based models. The purpose of this work is to produce a detailed hydrological and mechanical characterization of the soil affected by sha…

Corrigendum to “Assessing the performance of GIS- based machine learning models with different accuracy measures for determining susceptibility to gully erosion” [Sci. Total Environ. 664 (2019) 1117–1132]

Testing GIS-morphometric analysis of some Sicilian badlands

Abstract Calanchi badlands are erosion landforms characterized by areas with scarce or absent vegetation, steep slopes, knife-edge divides and high erosion rates. They are originated by a combination of morphogenetic processes, partly similar to those shaping bigger fluvial landforms, and therefore can be considered as field “laboratories.” This paper presents the results of an investigation carried out in two badland sites located in Sicily, where the geometry of 25 calanchi has been characterized using Digital Elevation Models having a mesh size equal to 2 m. For each landform, a power length–volume relationship is established. This relationship demonstrates that length of calanchi channe…

Valutazione dell’erosione del suolo nel bacino del Fiume San Leonardo (Sicilia centro-occidentale, Italia).

Soil erosion by water in Mediterranean environment: direct and indirect appraisal from test areas and catchments (EROMED. A project of National Interest financed by the Italian Ministry of University and Research: organization, goals and first results.

Assessment of Gully Erosion Susceptibility Using Multivariate Adaptive Regression Splines and Accounting for Terrain Connectivity

In this work, we assessed gully erosion susceptibility in two adjacent cultivated catchments of Sicily (Italy) by employing multivariate adaptive regression splines (MARS) and a set of geo-environmental variables. To explore the influence of hydrological connectivity on gully occurrence we measured the changes of performance occurred when adding one by one nine predictors reflecting terrain connectivity to a base model that included contributing area and slope gradient. Receiver operating characteristic (ROC) curves and the area under the ROC curve (AUC) were used to evaluate models performance. Gully predictive models were trained in both the catchments and submitted to internal (in the ca…

Data Mining Technique (Maximum Entropy Model) for Mapping Gully Erosion Susceptibility in the Gorganrood Watershed, Iran

Soil erosion is a serious problem affecting most of the countries. This study was carried out in Gorganrood Watershed (Iran), which extends for 10,197 km2 and is severely affected by gully erosion. A gully headcut inven- tory map consisting of 307 gully headcut points was provided by Google Earth images, field surveys, and national reports. Gully conditioning factors including sig- nificant geo-environmental and morphometric variables were selected as predictors. Maximum entropy (ME) model was exploited to model gully susceptibility, whereas the area under the ROC curve (AUC) and draw- ing receiver operating characteristic (ROC) curves were employed to evaluate the performance of the model.…

Exploring the effect of absence selection on landslide susceptibility models: A case study in Sicily, Italy

Abstract A statistical approach was employed to model the spatial distribution of rainfall-triggered landslides in two areas in Sicily (Italy) that occurred during the winter of 2004–2005. The investigated areas are located within the Belice River basin and extend for 38.5 and 10.3 km 2 , respectively. A landslide inventory was established for both areas using two Google Earth images taken on October 25th 2004 and on March 18th 2005, to map slope failures activated or reactivated during this interval. Geographic Information Systems (GIS) were used to prepare 5 m grids of the dependent variables (absence/presence of landslide) and independent variables (lithology and 13 DEM-derivatives). Mul…

Mapping Susceptibility to Debris Flows Triggered by Tropical Storms: A Case Study of the San Vicente Volcano Area (El Salvador, CA)

In this study, an inventory of storm-triggered debris flows performed in the area of the San Vicente volcano (El Salvador, CA) was used to calibrate predictive models and prepare a landslide susceptibility map. The storm event struck the area in November 2009 as the result of the simultaneous action of low-pressure system 96E and Hurricane Ida. Multivariate Adaptive Regression Splines (MARS) was employed to model the relationships between a set of environmental variables and the locations of the debris flows. Validation of the models was performed by splitting 100 random samples of event and non-event 10 m pixels into training and test subsets. The validation results revealed an excellent (…

Gully erosion in a small experimental catchment in SW Spain

GIS-MORPHOMETRIC ANALYSIS OF BADLANDS IN SICILY (ITALY)

Sicily is affected by severe erosion processes, locally causing large volumes of soil loss and high denudation rates. The effects of intense water erosion phenomena are testified by the occurrence of badlands that constitute a common landscape particularly in the central and southern areas of the Island, where slopes are frequently underlain by clay-rich deposits. This paper presents the first results of an investigation carried out in a badlands site located in the head sector of the Imera Meridionale river basin, where geometry of several erosion channels has been characterized. Since length of linear erosion landforms such as rills, ephemeral gullies and permanent gullies, has been prove…

A multi-scale regional landslide susceptibility assessment approach: the SUFRA_SICILIA (SUscettibilità da FRAna in Sicilia) project

The SUFRA project is based on a three level susceptibility mapping. According to the availability of more detailed data, the three scale for susceptibility mapping are increased respect to the ones suggested by the TIER group to 1:100,000, 1:50,000 and 1:25,000/1:10,000. The mapping levels exploit climatic, soil use (CORINE2009) and seismic informative layers, differentiating in the details of the core data (geology and topography), in the quality and resolution of the landslide inventory and in the modelling approach (Tab. 1). SUFRA_100 is based on a heuristic approach which is applied by processing a geologic layer (produced by ARTA integrating pre-CARG 1:100,000 geologic maps); the DEM e…

Geomorphological, chemical and physical study of “calanchi” landforms in NW Sicily (southern Italy)

Abstract This work deals with an integrated geomorphological and chemical–physical study of “calanchi” landforms in two sites (Ottosalme and Catalfimo) of NW Sicily (southern Italy), developed on dominant silty-clay deposits. The calanchi fronts are characterized by different morphological features and dominant geomorphic processes. Sharp knife-edged ridges and concentrated water runoff dominate at Ottosalme, and smoother landforms affected by mass movements (mud flows and translational slides) prevail at Catalfimo. We focused on some geochemical and physical parameters such as pH , total dissolved salts, sodium adsorption ratio ( SAR ), porosity, plastic and liquid limits as possible cause…

Application of RUSLE model for the assessment of soil erosion in the western sector of Palermo Mountains (north-western Sicily)

The aim of this work is to study the impact of vegetation cover on water erosion phenomena by exploiting an integrated approach to the assessment of soil loss rates. The investigated area is located in the western portion of the mountainous group named “Monti di Palermo” and occupies an area of approximately 475 km2; this area, which extends from sea level up to about 1,300 m, is mainly characterized by the presence of lithosols and luvisols laying above carbonate and terrigenous substrates. The assessment of erosion intensity was indirectly obtained by applying the RUSLE model, that allowed to estimate soil loss produced by rill-interrill erosion phenomena. Starting from topographical and …

The geo-hydrologic event in the Peloritan – Ionian area of 2009: debris-flow susceptibility assessment by means of forward logistic regression

On the 1st of October 2009, the area centred on the village of Giampilieri (Messina), on the Ionian side of the Peloritan belt, suffered thousands of landslides activated in the time lapse of about five hours, which caused 36 victims, more than 100 injured and more than 0.5M€ of damage to structures. This unprecedented phenomenon was triggered by an exceptional meteorological event, recorded at the foothills with 250mm of rain in just 8 hours; this amount of rainfall was cumulated to two previous events (16/IX: 75mm; 23/IX: 190mm) for a total amount of more than 500mm in less than two weeks. Due to the peculiar triggering conditions a huge number of debris flows involved the shallow weather…

Determining the optimal pixel size of topographical parameters for the prediction of hazardous geomorphological phenomenons of different magnitude: gullies and landslides

Soil erosion in Mediterranean environment: The conceptual approach of the EROMED Project to assess regional impacts of global change in Italy.

Comparison of differences in resolution and sources of controlling factors for gully erosion susceptibility mapping

Abstract Gully erosion has been identified as an important soil degradation process and sediment source, especially in arid and semiarid areas. Thus, it is useful to identify the spatial occurrence of this form of water erosion in the landscape and the most vulnerable areas. In this study, we explored the effects of different pixel sizes on some controlling factors extracted from a digital elevation model and remote sensing data when producing a gully erosion susceptibility map (GESM) of Ekbatan Dam Basin, Hamadan, Iran. An inventory map of the gully landforms was prepared based on global positioning system routes of the gullies, extensive field surveys, and visual interpretations of satell…

The Madonie Geopark (Italy): geological and geomorphological features

Soil erosion susceptibility assessment and validation using a geostatistical multivariate approach: a test in southern Sicily

A certain number of studies have been carried out in recent years that aim at developing and applying a model capable of assessing water erosion of soil. Some of these have tried to quantitatively evaluate the volumes of soil loss, while others have focused their efforts on the recognition of the areas most prone to water erosion processes. This article presents the results of a research whose objective was that of evaluating water erosion susceptibility in a Sicilian watershed: the Naro river basin. A geomorphological study was carried out to recognize the water erosion landforms and define a set of parameters expressing both the intensity of hydraulic forces and the resistance of rocks/so…

Landslide susceptibility assessment in Sicily: a key study in the central chain sector (Sicani Mounts)

Assessment of susceptibility to earth-flow landslide using logistic regression and multivariate adaptive regression splines: A case of the Belice River basin (western Sicily, Italy)

Abstract In this paper, terrain susceptibility to earth-flow occurrence was evaluated by using geographic information systems (GIS) and two statistical methods: Logistic regression (LR) and multivariate adaptive regression splines (MARS). LR has been already demonstrated to provide reliable predictions of earth-flow occurrence, whereas MARS, as far as we know, has never been used to generate earth-flow susceptibility models. The experiment was carried out in a basin of western Sicily (Italy), which extends for 51 km 2 and is severely affected by earth-flows. In total, we mapped 1376 earth-flows, covering an area of 4.59 km 2 . To explore the effect of pre-failure topography on earth-flow sp…

A multidisciplinary approach to the evaluation of the mechanism that triggered the Cerda landslide (Sicily, Italy).

Abstract The present paper describes a multidisciplinary approach to the evaluation of a seismically triggered landslide that occurred in the Cerda area (Italy) on September 6, 2002, about 1 h after an earthquake took place in the south Tyrrhenian Sea. The study was focused on an analysis of the role of the seismic input in triggering the landslide, in view of the evidence that no other mass movement was recorded in the adjacent areas despite geological and geomorphological spatial homogeneity. The studied area is located on a slope of the western flank of the Fiume Imera Settentrionale (Northern Sicily), which is made up of clayey–arenitic rocks. The slope inclines gently but is not unifor…

Soil erosion by water in Mediterranean environment: Italian assessment network of test areas and catchments (EROMED).

Susceptibility analysis for seismically-induced landslides: application to the 2001 earthquakes in El Salvador (C.A.)

<p>The geodynamic context in which El Salvador is located, made of a convergent structure characterized by the interaction among six different plates, together with the lithological characteristics of the outcropping rocks and soils (mainly corresponding to deeply weathered acid pyroclastites, basic effusive rocks and volcanic ashes), are responsible for the very high seismically-induced landslide susceptibility of the country. These predisposing factors were decisive on the occurrence of thousands of seismically-induced landslides caused by two huge earthquakes on 13<sup>th</sup> January and 13<sup>th</sup> February 2001…

Earth-flow susceptibility assessment in the Marvello River basin (Sicily, Italy)

In this study, statistical models of earth-flow susceptibility were prepared using logistic regression. The analyses were carried out in a small (51 km2) basin of western Sicily, where 1,376 earth-flows were identified. To predict the spatial distribution of the mapped landslides, outcropping lithology and seven topographic attributes were exploited as explanatory variables. Before calculating these variables, a reconstruction of the pre-failure topography was performed. To evaluate the predictive skill and the robustness of the models, two groups made of five random subsets of earth-flows and stable cells were prepared. Absences of the first group were selected as individual cells whereas …

Evaluating the effects of man-induced topographic changes in landscape structure on soil erosion by water: a case study in Sicily

Water erosion susceptibility mapping by applying Stochastic Gradient Treeboost to the Imera Meridionale River Basin (Sicily, Italy)

Abstract Soil erosion by water constitutes a serious problem affecting various countries. In the last few years, a number of studies have adopted statistical approaches for erosion susceptibility zonation. In this study, the Stochastic Gradient Treeboost (SGT) was tested as a multivariate statistical tool for exploring, analyzing and predicting the spatial occurrence of rill–interrill erosion and gully erosion. This technique implements the stochastic gradient boosting algorithm with a tree-based method. The study area is a 9.5 km 2 river catchment located in central-northern Sicily (Italy), where water erosion processes are prevalent, and affect the agricultural productivity of local commu…

Morphometric characterization of a calanchi inventory in Sicily, Italy

Calanchi are a frequent type of badland landscape of Sicily (Italy), usually located in the middle of crops or forests. They are characterized by heavily dissected terrains with unvegetated slopes, knife ridge edges, V-shaped valleys and channels with a dendritic pattern, which incise and extend headwards. Calanchi exhibit, in smaller temporal and spatial scales, many of the geomorphic processes and landforms that may by observed in a fluvial landscape, hence, this type of badland may be considered as micro-watersheds where geomorphic dynamics can be related to their geometric features. The aim of this investigation was to evaluate the morphometric characteristics of calanchi landforms in S…

Predicting the landslides triggered by the 2009 96E/Ida tropical storms in the Ilopango caldera area (El Salvador, CA): optimizing MARS-based model building and validation strategies

The main topic of this research was to evaluate the effect in the performance of stochastic landslide susceptibility models, produced by differences between the triggering events of the calibration and validation datasets. In the Caldera Ilopango area (El Salvador), MARS (multivariate adaptive regression splines)-based susceptibility modeling was applied using a set of physical–environmental predictors and two remotely recognized landslide inventories: one dated at 2003 (1503 landslides), which was the result of a normal rainfall season, and one which was produced by the combined effect of the Ida hurricane and the 96E tropical depression in 2009 (2237 landslides). Both the event inventorie…

Quantitative analysis of “calanchi” slopes in northern Sicily: erosion rates and their relationships with rainfalls and physico-chemical properties of terrains

Predicting sediment deposition rate in check-dams using machine learning techniques and high-resolution DEMs

Sediments accumulated in check dams are a valuable measure to estimate soil erosion rates. Here, geographic information systems (GIS) and three machine learning techniques (MARS-multivariate adaptive regression splines, RF-random forest and SVM-support vector machine) were used, for the first time, to predict sediment deposition rate (SR) in check-dams located in six watersheds in SW Spain. There, 160 dry-stone check dams (~ 77.8 check-dams km−2), accumulated sediments during a period that varied from 11 to 23 years. The SR was estimated in former research using a topographical method and a high-resolution Digital Elevation Model (DEM) (average of 0.14 m3 ha−1 year−1). Nine environmental-to…

Gully Erosion Susceptibility Mapping Using Multivariate Adaptive Regression Splines—Replications and Sample Size Scenarios

Soil erosion is a serious problem affecting numerous countries, especially, gully erosion. In the current research, GIS techniques and MARS (Multivariate Adaptive Regression Splines) algorithm were considered to evaluate gully erosion susceptibility mapping among others. The study was conducted in a specific section of the Gorganroud Watershed in Golestan Province (Northern Iran), covering 2142.64 km2 which is intensely influenced by gully erosion. First, Google Earth images, field surveys, and national reports were used to provide a gully-hedcut evaluation map consisting of 307 gully-hedcut points. Eighteen gully erosion conditioning factors including significant geoenvironmental and morph…

The 1968 Belice valley earthquake

Multi-scale regional landslide susceptibility assessment in Sicily (Italy): The Sufra Sicilia Project

Morphoevolutive models of the deep-seated gravitational slope deformation phenomena in Sicily Chain

Stochastic assessment of landslide susceptibility by using five different instability datasets: a case study from the southern sector of the “Via al Llano” highway (Colombia)

In this study, the ability of stochastic models to predict landslide susceptibility in the southern sector of the “Via al Llano” highway (Colombia) was assessed. To this aim, an inventory of landslides occurred in the area was prepared by analyzing images available in Google Earth. Multivariate Adaptive Regression Splines (MARS) was employed to model the spatial distribution of the following five data sets of unstable cells selected within each landslide: i) the highest cell (data set MAX), ii) the highest 10% of cells (data set SUP), iii) the lowest cell (data set MIN), iv) the lowest 10% of cells (data set INF), and v) the entire landslide area (data set BODY). The goal of our experiment …

Un approccio multi-scala per la valutazione della suscettibilità da frana a livello regionale: il progetto SUFRA (SUscettibilità da FRAna) in Sicilia

L’attuale versione del PAI (Piano Stralcio per l'Assetto Idrogeologico) disponibile per il territorio siciliano è fortemente dipendente dallo scenario di dissesti passati censiti e catalogati, sulla base dei quali, utilizzando un sistema di matrici di valutazione, è possibile ricavare le condizioni di rischio geomorfologico associato. Questo stadio costituisce un primo grande avanzamento delle conoscenze a partire dal quale è ora necessario procedere alla valutazione della suscettibilità da frana e all’adozione dunque di uno strumento di analisi territoriale con carattere previsionale. La realizzazione di una cartografia della suscettibilità da frana a scala regionale pone d’altra parte una…

An integrated geomorphologic-economic approach for valuing direct damage in agricultural areas caused by erosion process in a mediterranean environment (Italy)

Pantelleria island (Strait of Sicily): volcanic history and geomorphological landscape

Pantelleria is a volcanic island located in the Strait of Sicily, 95 km far from the Sicilian coastline and 67 km from Cape Bon (Tunisia). The volcanological history of the island begins approximately 324 ka BP and the last eruptive event was a submarine eruption that occurred on 1891 A.D. Eruptive activity was characterized by seven very intense explosive events, the latest being the Green Tuff (44 ka). They have all produced ignimbrite sheets that covered large sectors of the island. The landscape of the island mirrors the variety of the eruptive styles and their interplay with volcano-tectonics. The most evident geomorphological features are represented by: (i) the mantle-like distributi…

Landslide hazard analysis in the Iato River basin

Un nuovo modello per la stima dell'erosione in aree calanchive

Modelli predittivi di morfologie erosive e di frana nell'area di testata del bacino del fiume Imera Meridionale, Sicilia (Italia)

The 1st October 2009 Messina debris flows: first analysis for a susceptibility model

Elementi di Botanica forestale

Hillslope degradation in representative Italian areas. Just soil erosion risk or opportunity for development?

In recent years, much research have dealt with the impact of human and climate change on the morpho-evolution of Mediterranean catchments characterized by high ecological and cultural value. In this paper, we speculated how humans can influence hillslope degradation by reviewing the relationships between denudation processes and land use changes in some representative areas located in different Italian regions (i.e., Liguria, Tuscany, Basilicata, and Sicily). The selected study cases are characterized by different climatic and geological features, land use, and land management and can be considered indicative of the hillslope degradation issues that affected the Apennines during the last ce…

Calanchi landforms in south Italy: a comparison between Calabria and Sicilia case studies

Comparing binary logistic regression and stochastic gradient boosting techniques in debris-flows susceptibility modelling: application in North-Eastern Sicily

Stop 3.1: Monte Pellegrino

Evaluation of multi-hazard map produced using MaxEnt machine learning technique.

Abstract Natural hazards are diverse and uneven in time and space, therefore, understanding its complexity is key to save human lives and conserve natural ecosystems. Reducing the outputs obtained after each modelling analysis is key to present the results for stakeholders, land managers and policymakers. So, the main goal of this survey was to present a method to synthesize three natural hazards in one multi-hazard map and its evaluation for hazard management and land use planning. To test this methodology, we took as study area the Gorganrood Watershed, located in the Golestan Province (Iran). First, an inventory map of three different types of hazards including flood, landslides, and gul…

Gully erosion susceptibility assessment by means of GIS-based logistic regression: A case of Sicily (Italy)

article i nfo Article history: This research aims at characterizing susceptibility conditions to gully erosion by means of GIS and multivariate statistical analysis. The study area is a 9.5 km 2 river catchment in central-northern Sicily, where agriculture ac- tivities are limited by intense erosion. By means of field surveys and interpretation of aerial images, we prepared a digitalmap of thespatial distribution of 260 gulliesinthestudy area.Inaddition,fromavailable thematicmaps, a 5 m cell size digital elevation model and field checks, we derived 27 environmental attributes that describe the variability of lithology, land use, topography and road position. These attributes were selected f…

Comparing Logistic Regression and MARS approaches for gully erosion susceptibility evaluation in central-northern Sicily

Sicily: geological, structural and morphological features

Analisi della franosità del Fiume Iato

Landslide susceptibility modelling for extreme rainfall-triggered multiple landslides: a key study from the 2009 event in the Giampilieri Area(Sicily, Italy)

Analisi morfometrica di due aree calanchive in Sicilia (Italia)

Assessing the performance of GIS- based machine learning models with different accuracy measures for determining susceptibility to gully erosion

Assessing the performance of GIS- based machine learning models withdifferent accuracy measures for determining susceptibility togully erosionYounes Garosia, Mohsen Sheklabadia,⁎, Christian Conoscentib, Hamid Reza Pourghasemic,d, Kristof Van Ooste,faFaculty of Agriculture, Department of Soil Science, Bu Ali Sina University, Ahmadi Roshan Avenue, 6517838695 Hamedan, IranbDepartment of Earth and Sea Sciences (DISTEM), University of Palermo, Via Archirafi22, 90123 Palermo, ItalycCollege of Marine Sciences and Engineering, Nanjing Normal University, Nanjing, 210023, ChinadDepartment of Natural Resources and Environmental Engineering, College of Agriculture, Shiraz University, Shiraz, IraneA- Fo…

Analisi geostatistica della franosità nel bacino del Torrente Guddemi (Sicilia centro-occidentale)

Landslide susceptibility mapping using precipitation data, Mazandaran Province, north of Iran

Precipitation is a nonlinear and complex phenomenon and varies in time and space. It is also evident that there is a link between precipitation and shallow landslides, and precipitation is always considered as a landslide-triggering factor. This study aims to investigate the relationship between the characteristics of precipitation and the historical shallow landslides in Mazandaran Province, north of Iran. For this purpose, the spatial variability of rainfall was analyzed using monthly rainfall data collected at 15 synoptic stations distributed over the region between 1981 and 2014. Monthly precipitation and other derived parameters were used, and a hybrid model combining principal compone…

Monitoring of erosion on two calanchi fronts - rill, gully erosion and piping in northern Sicily (Italy)

Elementi di Geomorfologia Applicata

Extension of landslide susceptibility models: a test in the Platani river basin (Southern Sicily)

Geospatial analysis of drought tendencies in the Carpathians as reflected in a 50-year time series

Climate change is one of the most important issues of anthropogenic activities. The increasing drought conditions can cause water shortage and heat waves and can influence the agricultural production or the water supply of cities. The Carpathian region is also affected by this phenomenon; thus, we aimed at identifying the tendencies between 1960 and 2010 applying the CarpatClim (CC) database. We calculated the trends for each grid point of CC, plotted the results on maps, and applied statistical analysis on annual and seasonal level. We revealed that monthly average temperature, maximum temperature and evapotranspiration had similar patterns and had positive trends in all seasons except aut…

Multi-method evaluation of denudation rates in small mediterranean catchments

The paper presents the results of the research tasks of the Quantitative Geomorphology Working Group (of the Italian Association of Physical Geography and Geomorphology) focused on multi-method evaluation of denudation rates in small catchments of Italy. Several study areas are compared with the goal of quantifying the morphodynamic evolution in different response times and with traditional and innovative techniques. The final aims are the direct erosion monitoring, the geomorphic analysis for the comprehension of drainage basin morphodynamics, up to the geomorphological hazard evaluation. The catchments are key Mediterranean areas particularly sensitive to climatic and anthropic modificati…

Exporting a Google Earth™ aided earthflow susceptibility model: a test in central Sicily

Abstract In the framework of a regional landslide susceptibility study in southern Sicily, a test has been carried out in the Tumarrano river basin (about 80 km2) aimed at characterizing its landslide susceptibility conditions by exporting a ‘‘source model’’, defined and trained inside a limited (about 20 km2) representative sector (the ‘‘source area’’). Also, the possibility of exploiting Google Earth TM software and photo-images databank to produce the landslide archives has been checked. The susceptibility model was defined, according to a multivariate geostatistic approach based on the conditional analysis, using unique condition units (UCUs), which were obtained by combining four selec…

Predicting Earthquake-Induced Landslides by Using a Stochastic Modeling Approach: A Case Study of the 2001 El Salvador Coseismic Landslides

In January and February 2001, El Salvador was hit by two strong earthquakes that triggered thousands of landslides, causing 1259 fatalities and extensive damage. The analysis of aerial and SPOT-4 satellite images allowed us to map 6491 coseismic landslides, mainly debris slides and flows that occurred in volcanic epiclastites and pyroclastites. Four different multivariate adaptive regression splines (MARS) models were produced using different predictors and landslide inventories which contain slope failures triggered by an extreme rainfall event in 2009 and those induced by the earthquakes of 2001. In a predictive analysis, three validation scenarios were employed: the first and the second …

Geomorphology of the Capo San Vito Peninsula (NW Sicily): An Example of Tectonically and Climatically Controlled Landscape

The Capo San Vito peninsula is located along the north-westernmost sector of the Sicilian coastline. It is characterized by a complex geomorphological setting, where a large variety of coastal, gravity-induced and karst landforms allow the visitor to easily detect the interactions between Quaternary tectonics and climate changes as well as morphodynamic processes responsible for shaping the landscape. Thanks to natural reserves, the peninsula preserves a typical Mediterranean natural environment, marked by spectacular and suggestive landforms.

Investigating Limits in Exploiting Assembled Landslide Inventories for Calibrating Regional Susceptibility Models: A Test in Volcanic Areas of El Salvador

This research is focused on the evaluation of the reliability of regional landslide susceptibility models obtained by exploiting inhomogeneous (for quality, resolution and/or triggering related type and intensity) collected inventories for calibration. At a large-scale glance, merging more inventories can result in well-performing models hiding potential strong predictive deficiencies. An example of the limits that such kinds of models can display is given by a landslide susceptibility study, which was carried out for a large sector of the coastal area of El Salvador, where an apparently well-performing regional model (AUC = 0.87) was obtained by regressing a dataset through multivariate ad…

Forward logistic regression for earth-flow landslide susceptibility assessment in the Platani river basin (southern Sicily, Italy)

Forward logistic regression has allowed us to derive an earth-flow susceptibility model for the Tumarrano river basin, which was defined by modeling the statistical relationships between an archive of 760 events and a set of 20 predictors. For each landslide in the inventory, a landslide identification point (LIP) was automatically produced as corresponding to the highest point along the boundary of the landslide polygons, and unstable conditions were assigned to cells at a distance up to 8 m. An equal number of stable cells (out of landslides) was then randomly extracted and appended to the LIPs to prepare the dataset for logistic regression. A model building strategy was applied to enlarg…

Gully Erosion susceptibility assesment: a case study in the Magazzolo River Basin, Sicily, Italy.

Detection of homogeneous precipitation regions at seasonal and annual time scales, northwest Iran

Abstract Detection of homogeneous climate areas is a challenging issue, which can be affected by different criteria. One of the most prominent factors is choosing the time scale, which can lead to different spatial and temporal patterns. Total precipitation is a key factor in climatological studies, and studying its distribution is of utmost importance. The combination of principal components analysis and cluster analysis is used for homogeneous precipitation areas' detection. Hence, the spatial pattern of total precipitation was investigated in northwestern Iran during the past two decades (1991–2010) on seasonal and annual time scales. The results of clustering on each time scale were val…

Using topographical attributes to evaluate gully erosion proneness (susceptibility) in two mediterranean basins: advantages and limitations

Empirical multivariate predictive models represent an important tool to estimate gully erosion susceptibility. Topography, lithology, climate, land use and vegetation cover are commonly used as input for these approaches. In this paper, two multivariate predictive models were generated for two gully erosion processes in San Giorgio basin (Italy) and Mula River basin (Spain) using only topographical attributes as independent variables. Initially, nine models (five for San Giorgio and four for Mula) with pixel sizes ranging from 2 to 50 m were generated, and validation statistics were calculated to estimate the optimal pixel size. The best models were selected based on model performance using…

Exploring relationships between grid cell size and accuracy for debris-flow susceptibility models: a test in the Giampilieri catchment (Sicily, Italy)

Debris flows are among the most hazardous phenomena in nature, requiring the preparation of suscep- tibility models in order to cope with this severe threat. The aim of this research was to verify whether a grid cell-based susceptibility model was capable of predicting the debris- flow initiation sites in the Giampilieri catchment (10 km2), which was hit by a storm on the 1st October 2009, resulting in more than one thousand landslides. This kind of event is to be considered as recurrent in the area as attested by historical data. Therefore, predictive models have been prepared by using forward stepwise binary logistic regression (BLR), a landslide inventory and a set of geo- environmental …

Inquadramento geografico

3D- and spatial analysis GIS-tools for the study of sequences of relict sub-planar erosion surfaces

Improving transferability strategies for debris flow susceptibility assessment: Application to the Saponara and Itala catchments (Messina, Italy)

Abstract Debris flows can be described as rapid gravity-induced mass movements controlled by topography that are usually triggered as a consequence of storm rainfalls. One of the problems when dealing with debris flow recognition is that the eroded surface is usually very shallow and it can be masked by vegetation or fast weathering as early as one-two years after a landslide has occurred. For this reason, even areas that are highly susceptible to debris flow might suffer of a lack of reliable landslide inventories. However, these inventories are necessary for susceptibility assessment. Model transferability, which is based on calibrating a susceptibility model in a training area in order t…

PMT: New analytical framework for automated evaluation of geo-environmental modelling approaches

Geospatial computation, data transformation to a relevant statistical software, and step-wise quantitative performance assessment can be cumbersome, especially when considering that the entire modelling procedure is repeatedly interrupted by several input/output steps, and the self-consistency and self-adaptive response to the modelled data and the features therein are lost while handling the data from different kinds of working environments. To date, an automated and a comprehensive validation system, which includes both the cutoff-dependent and –independent evaluation criteria for spatial modelling approaches, has not yet been developed for GIS based methodologies. This study, for the fir…

Analisi mediante GIS dei processi di erosione nel bacino del Fiume Naro (Sicilia Centro-meridionale, Italia)

Predicting depositional areas of landslide susceptibility comparing four datasets extracted from landslide area: a case of study after rainfall-induced landslides by Ida Hurricane in 2009 on Ilopango Lake, El Salvador.

Hurricane Ida and low-pressure system 96E crossed Central American countries in 2009. However, in El Salvador, the torrential rainfalls caused many flooding and landslides. As a result, over 200 causalities and the destruction of several villages, and bridges occurred along the mountain slopes. The remote analysis allowed us to prepare an inventory of landslides that occurred after the Hurricane in a basin located in the northern part of Ilopango Caldera. Five groups of data sets were created using selected pixels of each landslide area in order to evaluate the capacity to predict the lowest and the entire landslide area. Multivariate Adaptive Regression Splines (MARS) were employed to mode…

Gully erosion susceptibility mapping using GIS-based multi-criteria decision analysis techniques

Abstract This research introduces a scientific methodology for gully erosion susceptibility mapping (GESM) that employs geography information system (GIS)-based multi-criteria decision analysis. The model was tested in Semnan Province, Iran, which has an arid and semi-arid climate with high susceptibility to gully erosion. The technique for order of preference by similarity to ideal solution (TOPSIS) and the analytic hierarchy process (AHP) multi-criteria decision-making (MCDM) models were integrated. The important aspect of this research is that it did not require gully erosion inventory maps for GESM. Therefore, the proposed methodology could be useful in areas with missing or incomplete …

Optimal slope units partitioning in landslide susceptibility mapping

In landslide susceptibility modeling, the selection of the mapping units is a very relevant topic both in terms of geomorphological adequacy and suitability of the models and final maps. In this paper, a test to integrate pixels and slope units is presented. MARS (Multivariate Adaptive Regression Splines) modeling was applied to assess landslide susceptibility based on a 12 predictors and a 1608 cases database. A pixel-based model was prepared and the scores zoned into 10 different types of slope units, obtained by differently combining two half-basin (HB) and four landform classification (LCL) coverages. The predictive performance of the 10 models were then compared to select the best perf…

Gis-analysis to assess landslide susceptibility in a fluvial basin of NW Sicily (Italy).

Abstract Landslide hazard assessment, effected by means of geostatistical methods, is based on the analysis of the relationships between landslides and the spatial distributions of some instability factors. Frequently such analyses are based on landslide inventories in which each record represents the entire unstable area and is managed as a single instability landform. In this research, landslide susceptibility is evaluated through the study of a variety of instability landforms: landslides, scarps and areas uphill from crown . The instability factors selected were: bedrock lithology, steepness, topographic wetness index and stream power index. The instability landform densities computed f…

Predicting storm-triggered debris flow events: application to the 2009 Ionian Peloritan disaster (Sicily, Italy)

Abstract. The main assumption on which landslide susceptibility assessment by means of stochastic modelling lies is that the past is the key to the future. As a consequence, a stochastic model able to classify past known landslide events should be able to predict a future unknown scenario as well. However, storm-triggered multiple debris flow events in the Mediterranean region could pose some limits on the operative validity of such an expectation, as they are typically resultant of a randomness in time recurrence and magnitude and a great spatial variability, even at the scale of small catchments. This is the case for the 2007 and 2009 storm events, which recently hit north-eastern Sicily …

First results of water erosion rates monitoring on two calanchi fronts in the Sicilian chain

Modeling landslide susceptibility by using GIS-analysis and multivariate adaptive regression splines

Landslide susceptibility may be evaluated by defining statistical relationships between the spatial distribution of past slope failures and the variability of landslide triggering factors. In this research, susceptibility to landsliding was assessed by employing multivariate adaptive regression splines (MARS), a statistical model that has been rarely used to this aim. The experiment was carried out in an area of central Sicily (Italy), which is severely affected by shallow landslides mainly occurring during the wet autumn- winter semester. Bedrock lithology and a set of primary and secondary topographic attributes were exploited as proxies of main landslide driving factors. The robustness o…

Exploiting ArcGIS and Google Earthtm to assess an earth flow susceptibility model in central Sicily

Valutazione dell’erosione prodotta dai processi di dilavamento nel bacino del Fiume della Mendola (Sicilia, Italia)

Morphometric analysis of two calanchi areas in Sicily (Italy) by exploiting high resolution Digital Elevation Models

In the Mediterranean areas, specifically in Sicily (Italy), irregular rainfalls, strong seasonal changes, scarce vegetation cover and, frequently, outcropping of clayey deposits favor water erosion phenomena. Badland landscapes are the result of severe erosion processes, characterized by steep slopes, sparse vegetation, high drainage density, rapid erosion rates and a shallow or non existing regolith profile. In this investigation we focused on the calanchi badland type, consisting of heavily dissected terrain with steep, unvegetated slopes and channels that rapidly incise and extend headwards. This research was carried out in two calanchi sites located in Sicily. The geometry of 25 badland…

Multi-parametric GIS analysis to assess gully erosion susceptibility: a test in southern Sicily, Italy

: A GIS-analysis was carried out in a test basin of southern Sicily, the Magazzolo River basin, in order to assess susceptibility conditions to gully erosion phenomena. The linear density of ephemeral and permanent gullies computed within each class of nine environmental variables was used to generate a gully erosion susceptibility map for the area. A validation procedure carried out in order to test the reliability of the adopted method highlighted a clear correlation between the occurrence of gullies and the computed susceptibility levels

Geomorphological setting of Madonie Geopark (Italy)

The Madonie Natural Park is characterized by relevant zoological and botanic aspects and by geological features so remarkable that since 2001 it has been incorporated into the European Geoparks Network. The Park is marked by a wide massif know as Madonie Mountains. In this area, segment of the Maghrebide-Apenninic chain, successions of Meso-Cenozoic lithologies and late- and post-orogenic deposits occur. The geomorphological setting is extremely varied and includes many landscapes characterising several Sicilian areas; it results from the interaction between geomorphological processes, tectonic movements and climatic changes. It is possible to identify five distinct sectors, each correspond…

Landslide hazard analysis using GIS, Fiumara di Rosmarino, North-Eastern Sicily

Binary logistic regression versus stochastic gradient boosted decision trees in assessing landslide susceptibility for multiple-occurring landslide events: application to the 2009 storm event in Messina (Sicily, southern Italy)

This study aims to compare binary logistic regression (BLR) and stochastic gradient treeboost (SGT) methods in assessing landslide susceptibility within the Mediterranean region for multiple-occurrence regional landslide events. A test area was selected in the north-eastern sector of Sicily (southern Italy) where thousands of debris flows and debris avalanches triggered on the first October 2009 due to an extreme storm. Exploiting the same set of predictors and the 2009 event landslide archive, BLR- and SGT-based susceptibility models have been obtained for the two catchments separately, adopting a random partition (RP) technique for validation. In addition, the models trained in one catchm…

Morphometric and hydraulic geometry assessment of a gully in SW Spain

Abstract Gully erosion represents one of the most significant types of land degradation in the Mediterranean areas, giving place to important on- and off-site effects. In this paper, a second-order gully located in SW Spain is analyzed. Along the gully, 28 cross-sections were established and measured with a Leica TCRM1102 laser total station, approximately every 6 months from 2001 to 2007. The sections were located at variable distance, placing them in areas where active erosion was evident. In total, 13 field measurements were carried out, and the geometric characteristics of 28 cross-sections were obtained. Morphometric analyses were carried out in both the main gully and a tributary reac…

Landslide susceptibility zonation by exploiting GIS tools and two statistical methods: binary logistic regression and multivariate adaptive regression splines. A test in western Sicily (Italy)

In the recent years advanced statistical methods and GIS tools have been frequently used to assess landslide susceptibility. The latter is estimated by establishing statistical relationships between landscape characteristics and spatial distribution of past slope-failures. These are mapped mainly by recognizing changes on slope morphology produced by gravity. Despite of this, most of the researches on landslide susceptibility do not consider that slope-failures modify topography and associate high probability of landsliding with topographic characteristics that differ from those that led slope-failures. In this research we analyzed landslide susceptibility in the basin of the Malvello river…

Exploring relationships between pixel size and accuracy for debris flow susceptibility models: a test in the Giampilieri catchment (Sicily, Italy).

Debris flows are among the most hazardous phenomena in nature, which typically take the form of multiple-occurrence regional landslide events triggered by intense driving inputs such as storms or earthquakes. The main tasks of this study were to verify whether cell-based susceptibility models is capable of predicting debris flow initiations in the Giampilieri catchment (southern Italy) and to explore the relationships between the pixel size of the adopted mapping units in terms of predictive performances of the derived models. The Giampilieri catchment is a small area (10km 2 ) hit by a storm on the 1 st October 2009 which resulted in the triggering of more than one thousand landslides and …

Elaboración de modelos 3D de diferentes morfologías y escalas utilizando técnicas Structure-from-Motion y fotografías terrestres

En este trabajo se evalúan los métodos de foto-reconstrucción automatizada basados en el uso conjunto de las técnicas Structure from Motion (SfM) y Multi-View Stereo (MVS) para medir, monitorizar y cuantificar la dinámica de tres formas geomorfológicas: i) el glaciar rocoso del Corral del Veleta (Granada, España), ii) un paisaje de cárcavas de tipo calanchi (Sicilia, Italia) y ii) cinco pequeñas cabeceras de cárcava (Cáceres, España). Se incluyen en este trabajo los resultados sobre la precisión, utilidad y aplicabilidad de estas técnicas. Para la cuantificación de la precisión se utilizan el error cuadrático medio (RMSE) de los puntos de control que se emplean en la georreferenciación y la…

Susceptibility assessment for flows landslide in the upper Salso river basin (Sicily)

Predicting gully occurrence at watershed scale: Comparing topographic indices and multivariate statistical models

In this study, the ability of five topographic indices to predict the gully trajectories observed in two adjacent watersheds located in Sicily (Italy) was evaluated. Two of these indices, named MSPI and MTWI, as far as we know, have never been employed to this aim. They were obtained by multiplying the stream power index (SPI) and the topographic wetness index (TWI), respectively, by the convergence index (CI). The predictive ability of the topographic indices was measured by using both cut-off independent (AUC: area under the receiver operating characteristic curve) and dependent statistics (Cohen's kappa index κ, sensitivity, specificity). These statistics were calculated also for 100 MAR…

The role of the diagnostic areas in the assessment of landslide susceptibility models: a test in the sicilian chain

Abstract The aim of the research was to verify and compare the predictive power of different diagnostic areas in assessing landslide susceptibility with a multivariate approach. Scarps, landslide areas (the union between scarp and accumulation zones) and areas uphill from crowns, for rotational slides, source or scarp areas and landslide areas, for flows, have been tested. A multivariate approach was applied to assess the landslide susceptibility on the basis of three selected conditioning factors (lithology, slope angle, and topographic wetness index), which were combined in a Unique Condition Unit (UCU) layer. By intersecting the UCU layer with the vector layer of the diagnostic areas, la…

GPS Monitoring of the Scopello (Sicily, Italy) DGSD Phenomenon: Relationships Between Surficial and Deep-Seated Morphodynamics

The Scopello area, which is located along the north-western Tyrrhenian coastal sector of the Sicilian chain (Italy), is widely affected by Deep-seated Gravitational Slope Deformation (DGSD) phenomena, which are mainly the result of a geomorphologic setting marked by the outcropping of an overthrust plan, limiting a brittle fractured carbonate slab, laid onto a ductile marly-clayey substratum. Due to the very advanced stage of the deformation phenomena, a coupled morphodynamic style has established between shallow landslides and DGSD phenomena, affecting the exhumed ductile substratum and the overlaying rigid dismantled slab, respectively. A GPS network was realized for monitoring the Scopel…

Morphometric analysis of calanchi areas by low-altitude flight

Prediction of debris-avalanches and -flows triggered by a tropical storm by using a stochastic approach: An application to the events occurred in Mocoa (Colombia) on 1 April 2017

Abstract Landslides are among the most dangerous natural processes. Debris avalanches and debris flows in particular have often caused casualties and severe damage to infrastructures in a wide range of environments. The assessment of susceptibility to these phenomena may help policy makers in mitigating the associated risk and thus it has attracted special attention in the last decades. In this experiment, we assessed susceptibility to debris-avalanche and -flow landslides by using a stochastic approach. Two different modeling techniques were employed: i) Multivariate Adaptive Regression Splines (MARS) and ii) Logistic Regression (LR). Both MARS and LR allow for calculating the probability …

A new empirical model for estimating calanchi Erosion in Sicily, Italy

Abstract Calanchi (plural of calanco) are typical badland landforms of the Italian landscape. They consist of dense networks of V-shaped valleys, with a sparse or absent vegetation cover, which frequently develop on unconsolidated or poorly consolidated clayey deposits. In this paper, the dimensional analysis and the incomplete self-similarity theory were used to deduce a model relating the volume of sediments eroded from the calanchi area to a set of geometric attributes of their tributary areas. The morphometric characteristics of 209 calanchi basins were used to calibrate and validate the model. The predictive skill of the model was assessed by calculating the mean square error and the N…

Application of the group method of data handling (GMDH) approach for landslide susceptibility zonation using readily available spatial covariates

Abstract Landslide susceptibility (LS) mapping is an essential tool for landslide risk assessment. This study aimed to provide a new approach with better performance for landslide mapping and adopting readily available variables. In addition, it investigates the capability of a state-of-the-art model developed using the group method of data handling (GMDH) to spatially model LS. Furthermore, hybridized models of GMDH were developed using different metaheuristic algorithms. The study area was the Bonghwa region of South Korea, for which an accurate landslide inventory dataset is available. We considered a total of 13 spatial covariates (altitude, slope, aspect, topographic wetness index, val…

Evaluation of debris flow susceptibility in El Salvador (CA): a comparison between Multivariate Adaptive Regression Splines (MARS) and Binary Logistic Regression (BLR)

In the studies of landslide susceptibility assessment, which have been developed in recent years, statistical methods have increasingly been applied. Among all, the BLR (Binary Logistic Regression) certainly finds a more extensive application while MARS (Multivariate Adaptive Regression Splines), despite the good performance and the innovation of the strategies of analysis, only recently began to be employed as a statistical tool for predicting landslide occurrence. The purpose of this research was to evaluate the predictive performance and identify possible drawbacks of the two statistical techniques mentioned above, focusing in particular on the prediction of debris flows. To this aim, an…

Measuring, modelling and managing gully erosion at large scales: A state of the art

Soil erosion is generally recognized as the dominant process of land degradation. The formation and expansion of gullies is often a highly significant process of soil erosion. However, our ability to assess and simulate gully erosion and its impacts remains very limited. This is especially so at regional to continental scales. As a result, gullying is often overlooked in policies and land and catchment management strategies. Nevertheless, significant progress has been made over the past decades. Based on a review of >590 scientific articles and policy documents, we provide a state-of-the-art on our ability to monitor, model and manage gully erosion at regional to continental scales. In this…

A GIS-based approach for gully erosion susceptibility modelling: a test in Sicily, Italy

The aim of this study is to analyze the susceptibility conditions to gully erosion phenomena in the Magazzolo River basin and to test a method that allows for driving the factors selection. The study area is one of the largest (225 km2) watershed of southern Sicily and it is mostly characterized by gentle slopes carved into clayey and evaporitic sediments, except for the northern sector where carbonatic rocks give rise to steep slopes. In order to obtain a quantitative evaluation of gully erosion susceptibility, statistical relationships between the spatial distributions of gullies affecting the area and a set of twelve environmental variables were analyzed. Stereoscopic analysis of aerial …

Landslide susceptibility assessment in the upper Imera river basin (central Sicilian chain)

Landslide analysis in the Iato river basin (north-western Sicily, Italy)