1,721,031 research outputs found
Geomorphological hazard and human impact in mountain environments
No full textSi tratta dello Special Issue della rivista Geomorphology che raccoglie gli atti del Simposio Internazionale tenutosi a Dornbirn (Austria) nel 2002
Landslides as a geomorphological proxy for climate change: A record from the Dolomites (northern Italy)
No full textThis study investigates relationships between climate changes and hillslope evolution in the Dolomites (eastern Alps, Italy), during the Late Quaternary, with particular attention paid to landslide processes. The basic premise is that modifications in landslide frequency may be interpreted as changes in the hydrological conditions of slopes, which are in turn controlled by climate. After the statistical analysis of a data set composed of 73 conventional radiocarbon ages, obtained from 24 landslides, four periods of enhanced landsliding have been identified: I. from 10,700 to 8400 cal BP, between Younger Dryas and the Preboreal; II. from 8200 to 6900 cal BP, during the older Atlantic; III. from 5800 to 4500 cal BP, between Atlantic and Subboreal; IV. from 4000 to 2100 cal BP, between Subboreal and Subatlantic.These periods have been compared with different Late Glacial and Holocene paleoclimatic records, to check the correspondence between periods of enhanced landslide activity and cold and humid spells recognized at different spatial scales. As the records show, in the study areas, slope instability processes can be considered geomorphological indicators of climatic changes and to a certain extent reliable proxies of environmental evolution
General Symposia - G07 Geomorphology - "Landscape Sensitivity" - 32nd International Geological Congress - Florence - Italy, August 20-28, 2004
No full textSi tratta del volume di atti della sessione "Landscape sensitivity" tenutasi in occasione del Congresso Internazionale di Geologia di Firenze 2004
Preface [Introduzione al volume di atti relativo alla sessione Landscape sensitivity]
No full textSi tratta dell'introduzione al volume di atti relativo alla sessione "Landscape sensitivity" tenutasi in occasione del Congresso Internazionale di Geologia di Firenze 2004
La Geologia della Rupe di San Leo
No full textL’articolo illustra una nuova carta geologica in scala 1/2000 della Rupe di San Leo, che è una spettacolare e delicata forma del rilievo posta al centro della Coltre della Val Marecchia. La Rupe è costituita da una successione epiligure che comprende i calcari della F.ne di San Marino e le arenarie della F.ne di Monte Fumaiolo, mentre il substrato della Rupe è costituito da unità liguri prevalentemente argillose. Per mostrare la geometria tridimensionale degli ammassi rocciosi che compongono la Rupe, alla carta geologica 1/2000 sono stati aggiunti dieci line-drawing dei confini geologici affioranti nelle pareti perimetrali. Dall’interpretazione dei dati rilevati sono stati ricavati caratteri stratigrafici inediti e una ben definita cronologia di deformazione. L’elemento tettonico più interessante è la grande faglia distensiva a basso angolo, di origine gravitativa, che affiora alla base delle pareti W, S ed E della Rupe. La faglia di San Leo fa parte di un sistema riconoscibile dal Monte Fumaiolo a Perticara, Torriana, Verucchio e San Marino. Il rilevamento e la datazione di questo sistema di faglie è essenziale per ricostruire la cinematica della coltre della Val Marecchia
Geomorphological hazard and human impact in mountain environments: an introduction
No full textSi tratta dell'introduzione al volume di atti del Simposio Internazionale dell'International Association of Geomorphologists tenutosi a Dornbirn (Austria) nel 2002
Quantum fluctuations in multimode semiconductor lasers
No full textWe derive a quantum macroscopic model for a multimode semiconductor laser, starting from a complete microscopic description. Nonlinear gain terms describing saturation and mode-mode interaction are obtained by a suitable treatment of the spectral hole burning in the distribution of carriers. In the case in which there are two neighbouring active longitudinal modes above threshold and for quiet pumping, we calculate the spectrum of the total intensity fluctuations at zero frequency. For moderate pumping level the nonlinear gain terms do not reduce the degree of anticorrelation between modes, leaving the squeezing in total intensity unchanged with respect to the single-mode case. Only for very high pumping does the nonlinear gain suppression become relevant, and the total intensity noise is increased
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Paleoclimatic significance of Holocene slope instability in the Dolomites (Italy)
No full textThis paper deals with the use of records of past landslide events in the study of climate changes. The dating of past landslide events is a useful tool to reconstruct the evolution of the slope-system at a broad temporal scale and to recognize the different formative events it has undergone. When the environmental context can be traced by means of a multidisciplinary approach which comprises geomorphological, sedimentological, palaeobotanical, dendrochronological and archaeological analyses, then a deep understanding of the relationship between the possible triggering factors and the slope response can be achieved. The goal is to recognize changes of environmental factors which condition landsliding processes such as climate, seismic activity, vegetation and land use, trying to identify the relationship between landslide events and their triggering process, which is known to be complicated by the behaviour and the properties of the hillslope system. With reference to the results of some case studies in the Dolomites, the conceptual and methodological aspects of the topic are here discussed
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