Laura Melelli

Morphotectonics of the Upper Tiber Valley (Northern Apennines, Italy) through quantitative analysis of drainage and landforms

We present a geomorphological analysis of the recent extensional tectonics of a Quaternary continental basin in the Northern Apennines (Italy). The study area is focused on Upper Tiber Valley (UTV), a basin elongated for 70 km in NNW-SSE direction hosting the Tiber River. The area is characterized by a series of features that make it an excellent case study: (i) homogeneity of lithology (ii) active faults, and (iii) strong morphogenetic activity. In this study, 36 hydrographical basins, tributaries of Tiber River, have been analysed. A preliminary qualitative geomorphological setting was outlined pointing out that the drainage river network shows meaningful evidence of tectonic control, such as abrupt changes in stream directions, knickpoints and steepness anomalies alignments along meaningful length in adjacent basins. Besides, the tectonic control is well marked in base level changes and consequent tectonically induced downcutting. Signs of neotectonics are highlighted by structural landforms too. The entrenchment of alluvial fans, the triangular facets and the fault planes are mapped by field survey and aerial photo interpretation. In addition, a quantitative analysis was also performed. Linear, areal and volumetric indexes related to drainage basins and river networks are taken into account. The geometry of the escarpments delimiting the basin and the landforms detected along the adjacent piedmont are investigated. The ranges of values, according to the existing literature, confirm a condition of wide-ranging morphological disturbance. In the central part of the study area, while the western basins are almost in equilibrium, the eastern ones reveal clear signs of disequilibrium, this is particularly evident along the distal segment of the river network. These data, joined with the characteristics of the escarpment and piedmont junction, confirm that the neotectonic activity, in the centre and in the eastern side of the basin, is the main factor controlling the morphological system.

Modelling risk hurricane elements in potentially affected areas by a GIS system

In the last decade, modelling hurricanes in potentially affected areas using geographical information systems (GIS) and geospatial cyberinfrastracture (GCI) has become a major topic of research. Despite some basic approaches, some unsolved questions are still under discussion. The disastrous effects of hurricanes on communities are well known, however there is a need to better understand the hazard contributions of the different components related to a hurricane, such as storm surges, floods and high winds. In this paper, the selected approach is to determine an onset zoning from a set of attributes that are considered to govern the hurricane while examining the influence of each individual component that produces the final exposure. To this end, this study assesses the different components using parameters derived from topography, bathymetry and hurricane physical indexes. Key attributes are the river network, the topography, the wetness index and the offline bathymetry. Complementary data include the CMORPH rain dataset and the hurricane track together with its structure model, both based on National Oceanic and Atmospheric Administration (NOAA) datasets. Total hazard results were then overlaid with population data in the overall assessment of elements at risk. The approach, which made use of a number of available global and free datasets, was then validated on a regional basis using ground data collected by the World Food Programme (WFP) over the study area (Central America region) for a specific hurricane.

Geomorphodiversity index: Quantifying the diversity of landforms and physical landscape

The physical landscape is the mosaic resulting from a wide spectrum of environmental components. The landforms define the variety, or diversity, of the geomorphological component: the geomorphodiversity. Landforms are usually represented in thematic maps where the scale and the graphic solutions are widely heterogeneous. Since geomorphological maps are not always easy to obtain and standardize, topography might be used as a proxy to infer the morphological signature. To recognize, evaluate, and in some cases promote the geomorphodiversity of an area, a numerical assessment is preferable. Through the use of quantitative approaches, indexes can be defined which quantitatively characterize the physical landscape in a discretized space consisting of continuous and regular cells. In this approach each cell is labelled with an algebraic value, which increases with the diversity degree. In this paper a quantitative index for geomorphodiversity is estimated stressing the topographic variables derived from Digital Elevation Models in a GIS environment. The resulting index is the sum of the variety of each terrain parameter taken into account. The areas characterized by the highest value of geomorphodiversity index show a good correspondence with well-known situations in the region where not always the geological heritage is properly acknowledged. The areas characterized by the lowest value of geodiversity correspond to the center of some intermountain basins of the region. Being the index strictly related to the topographic variety, this result is quite obvious but not easily predictable since in some flat areas the index is higher. Comparing the results with the geomorphological map of the area performs a validation procedure for the method. A positive correlation is found between the index calculated and the presence/absence of landforms. The paper shows that the index is a useful and simple tool for the identification, analysis and promotion of the geological heritage.

The Etruscan “Volumni Hypogeum” Archeo-Geosite: New Sedimentological and Geomorphological Insights on the Tombal Complex

Geoarchaeology is a multidisciplinary field that uses the methods and the contents of Earth Sciences for a more complete and detailed investigation of historical sites (Waters 1992; Rapp and Hill 1998; Goldberg and Macphail 2005; Ghilardi and Desruelles 2009). In particular, the geoarchaeologycal investigation of a site focuses on the study of stratigraphic sequences and on the clear understanding of the geomorphological and palaeogeographic setting of the area. One of the main goals is to better recognize the ancient environmental context in which the settlement was established. This approach is rather recent, given that the systematic stratigraphic analysis of excavation sites has been used only since the end of the nineteenth century, while the geomorphological reconstruction of the palaeogeographic environment has been applied only since the 1980s (Ghilardi and Desruelles 2009). Moreover, important information is obtained from the study of environmental changes occurred from the period during which the settlement was established until nowadays. Since the location of a historical place is strictly related to the geographica l condi t ions of the s i t e , the palaeogeographic study is essential to localize the position of a site or to understand its time evolution. In this context, the use of geographical information systems (GIS) technology plays an important role, allowing for the investigation of natural and/or artificial characteristics of the Earth surface (Moore et al. 1991; Nelson et al. 2009; Melelli et al. 2012). The great flexibility of these techniques allows us to compare and integrate data provided by Social Sciences as well as Sciences, thus providing unique indications for Geoarchaeology. Until now the integration of Earth Sciences and Archaeology has been mainly used for archaeological purposes. Indeed, Earth Sciences have been used as a Btool^ for archaeological research, with a few feedbacks or advantages for the geological field. On the contrary, now, new potential connections are emerging, with the development of new branches of the Earth Sciences, including the geological heritage identification and promotion. Geological outcrops and geomorphological features characterized by intrinsic, cultural, economic, scientific and educational values are defined in the scientific literature as Bgeosites^ (Panizza and Piacente 2008). These geological heritages are defined as Bany place, area or territory where you can define a geological and geomorphological interest for conservation^ (Grey 2004); in addition to the abiotic values, they can have a strong historical, archaeological and cultural relevance (Melelli 2014; Pica et al. 2015). In order to promote the geological heritage with cultural added values, some archaeological sites, where the stratigraphic or geomorphological surrounding conditions are relevant, can be defined as Barchaeo–geosite^ (Gregori et al. 2005; Gustavsson et al. 2006; Gungor et al. 2012). Moreover, this new approach for the investigation of an archaeological site allows us to export its value from the academic context to a more wide audience, thus increasing its touristic value, and consequently, the economic value of the area. Accordingly, geotourism (a particular branch of tourism interested in the knowledge of the geological heritage) is the * Laura Melelli laura.melelli@unipg.it

The hermitage of Cerbaiolo (Tuscany, Italy): stability conditions and geomorphological characterization

The Italian cultural heritage is one of the most noticeable in the world; an important part of it is subjected to natural hazard and risk conditions. Religious buildings, due to their location on impervious sites are particularly exposed to landslides. In this paper we study the hermitage of Cerbaiolo (Tuscany, central Italy). The hermitage, founded in the 8th century as a Benedictine monastery is now a Franciscan Women Institute seat. The buildings are on the edges of a limestone plate overlapped to a clayey formation. Falls, toppling and slides are present along the limits of the plate due to the geomechanics properties of the rock and to the contrast between the two lithological complexes. In order to identify the main joint sets affecting the rock mass a structural-geological survey was carried out and four sets are identified. The rock plate was classified according to Bieniawski, Barton and Geological Strength Index approaches. The outcomes confirm the predisposing factors to mass movements, corresponding to the intensity and characteristics of fracturing of the rock mass. With regard to the slope stability analysis, a failure mechanism involving sliding along a single plane (plane failure) was assumed on the first approximation. The analyses take into account the presence of tension cracks as an indicator factor for the instability phenomenon. The results of stability analyses, performed in static and seismic conditions, indicate a widespread instability condition. The dip slope direction, the properties and type of discontinuities and the local variation of composition influence the hazard assessment.

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 modifications. The efforts of the Working Group are finalized to favour scientific collaboration activities among members with the aim of strengthen the potential of Quantitative Gomorphology in morphodynamic studies.

The Use of Remote Sensed Data and GIS to Produce a Digital Geomorphological Map of a Test Area in Central Italy

Geomorphological maps report the erosion and depositional relief landforms, including submarine ones, highlighting the morphographic and morphometric characters and interpreting the endogenous and exogenous morphological processes, both past or present, that produce and shape the topographic relief. In this kind of maps, the chronological sequence is also reported, distinguishing between active and inactive landforms. The geomorphological mapping, in addition to its scientific value, is the necessary starting point of different studies such applied geology and environmental protection investigations for socio-economic improvement.

Detecting Alluvial Fans Using Quantitative Roughness Characterization and Fuzzy Logic Analysis

This research, based on a similarity geometric model, uses quantitative roughness characterization and fuzzy logic analysis to map alluvial fans. We choose to work in the Italian central Apennine intermountain basins because much human activities could mask this kind of landforms and because the timing of alluvial deposition is tied to land surface instabilities caused by regional climate changes. The main aim of the research is to understand where they form and where they extent in an effort to develop a new approach using the backscatter roughness parameters and primary attributes (elevation and curvature) derived from the SRTM DEM. Moreover, this study helps to provide a benchmark against which future alluvial fans detection using roughness and fuzzy logic analysis can be evaluated, meaning that sophisticated coupling of geomorphic and remote sensing processes can be attempted, in order to test for feedbacks between geomorphic processes and topography.

Relief, Intermontane Basins and Civilization in the Umbria-Marche Apennines: Origin and Life by Geological Consent

The landscape of the Umbria-Marche Apennines (Central Italy) shows a rhythmic sequence of “whaleback” anticlinal ridges separated by longitudinal synformal valleys. In this topographic arrangement, flat-floored tectonic depressions appear which enclose a wide range of landforms, and witness the continuous balance between tectonic forces, Quaternary climatic phases and drainage network adjustment. Fault scarps and triangular facets characterize the bordering slopes where thick talus deposits and landslides highlight the gravitational component. Karstic landforms as dolines and caves and fluvial features testify to the action of water. The resulting landscape is, for a visitor, like an incomparable geological handbook.

Modelling Hurricane Related Hazards and Risk through GIS for Early Warning Systems

Andrea Taramelli1, Massimiliano Pasqui2, Laura Melelli3, Monia Santini4 and Alessandro Sorichetta5 1ISPRA, Institute for Environmental Research, via di Casalotti, 300, Roma, 2Institute of Biometeorology – National Research Council, Roma, 3Department of Earth Science, University of Perugia, Perugia, 4euroMediterranean Center for Climate Changes, Lecce, 5Dipartimento di Scienze della Terra “Ardito Desio” , Universita degli Studi di Milano, Milano, Italy