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Karst geo-hazards: Causal factors and management issues Naravne nesreče na krasu: Vzročni dejavniki in vprašanja upravljanja
Full text linkKarst terranes exhibit spectacular landforms that are often exploited as natural parks and show caves, and hosts very important natural resources. Further, karst terranes cover 20% of the Earth’s surface and provides 20-25% of high-quality groundwater for drinking water. The fragility of karst environments makes it highly vulnerable to a variety of different geological hazards (or geo-hazards). This is due to its peculiar geological and hydrological features such as sinkholes and caves. In particular, the strict connection between surface and subsurface features emphasizes the fragile nature of karst. The occurrence of geo-hazards in karst terranes greatly differs from other natural settings. Natural and man-induced subsidence and sinkholes, slope movements favored by karst conduits and caves, flash floods related to inability of the system to manage water from heavy rainstorms, and pollution caused directly or indirectly by human actions are the main types of geo-hazards typical of karst terranes. Although mostly related to natural processes, their occurrence and consequent damage to both the natural and anthropogenic environment are often caused or exacerbated by man. As a consequence, management of karst terranes cannot be enacted without taking into account the peculiar features and behavior of karst terranes and aquifers, and the delicate balance with the different types of geo-hazards that may occur. Specific management actions should, therefore, be pursued in this fragile environment, with the intention of safeguarding the natural resources, biota, and population
Multi-temporal analysis of slope movements in the Southern Apennines of Italy.
Full text linkMany types of thematic maps dealing with slope movements have been proposed in the scientific literature to
describe the features and activity of landslides. One of the most common is the classical landslide inventory map:
this can be defined as a photograph of the landscape at a given time, that is the moment of the field surveys, or
the date of the air photographs and/or satellite images used for mapping. Unless further data (such as dates of
occurrence of the landslides, frequency of movement, etc.) are not added, it does nothing more than depicting the
instability situation at that given time. In order to reach more insights into the history and evolution of unstable
slopes, a multi-time approach must be performed. This can be carried out through a multi-temporal analysis, based
upon aerial photo interpretation of different years, possibly integrated by field surveys. Production of landslide
inventory map for each available set of air photos results in the final output of landslide activity maps (LAMs),
deriving from comparison of the individual inventory map. LAMs provide insights into the evolution of the
landslide process, allowing to reconstruct a relative history of the mass movement, and to highlight the most active
sectors in time. All these information may result extremely useful to correlate likely movements to anthropogenic
activity or specific triggering factors, such as a seismic event or a rainstorm. In addition, LAMs can also be of
effective use in evaluating the efficiency of remediation works.
The Southern Apennines of Italy are intensely affected by a variety of slope movements, that interest very different
settings and are at the origin of severe damage to the built-up environments, claiming every year a high number of
casualties. Notwithstanding the availability of landslide maps for the whole Italian territory, with very good detail
at local sites of interest, what is often lacking over the country is a thorough knowledge of the overall history of the
slopes, in terms of temporal evolution of the phenomena. LAMs can provide a significant contribution in covering
this lack, and allowing one to better understand the presently observed situation within a more general framework.
Starting from the above considerations, some examples of LAMs are presented in this article, covering different
geological and morphological contexts of the Southern Apennines of Italy, aimed at highlighting the potentiality
of such an approach for the understanding of the landsliding activity, at the same time giving significant hints to
be used for remediation and/or stabilization works and for land management issues
Artificial caves as a possible danger: sinkholes and other effects at the surface
Full text linkArtificial caves may represent a possible danger, threatening the public and private properties. Presence of
underground cavities beneath built-up areas implies situations of potential risk for all the man-made infrastructures
and constructions above. Nevertheless, such a risk remains unknown until an effective knowledge
about the real extension, the typology, and the stability conditions of the caves has been reached.
Cavers must be well aware of such a risk, and be ready to provide a contribution in facing the problems that
might occur. In many occasions, development of deformations at the surface, up to subsidence and eventually
formation of sinkholes, has caused severe direct damage, and produced a number of related problems, from
inconveniences to circulation for the local population, to decreased value of properties, and so on. The conditions
possibly leading to occurrence of sinkholes must be therefore object of study by cavers, since they are the
only “eyes” that have a direct possibility of inspection and monitoring of the underground.
Artificial cavities, once abandoned, are subject to degradation of the rock mass, which may also be favored
by water infiltration, presence of wastes, or other anthropogenic actions (i.e., overcharge, vibrations due to
traffic, etc.). Identification of the first signs of instability underground, in the form of tension cracks, deformations
along the wall of the cavities, and first detachment of volumes of rocks, is crucial to assess the
instability conditions at the site, and to plan the necessary interventions.
All the above issues will be dealt with in this contribution, by means of some examples from Apulia region
(southern Italy) where in recent years several episodes have occurred, mostly related to underground quarries.
This latter typology of artificial caves has been identified by far as the most dangerous typology of artificial
cavity concerning instability phenomena and the likely effects to the human societ
Problematiche di dissesto idrogeologico connesse a cavità di origine naturale e antropica in Puglia
No full textLa notevole diffusione di cavità, sia di origine
naturale che antropica, sul territorio pugliese è all’origine
dell’elevata frequenza di situazioni di dissesto idrogeologico
derivanti da fenomeni di instabilità nel sottosuolo, la cui propagazione
verso l’alto può eventualmente arrivare a produrre
la formazione di veri e propri sprofondamenti (sinkholes).
Date le caratteristiche geologiche della regione (in gran parte
caratterizzata da affioramenti di rocce solubili) il carsismo
costituisce uno dei principali agenti di modellamento del paesaggio,
sia in superficie che nel sottosuolo. A ciò si aggiungono
le cavità scavate nel corso dei secoli dall’attività
antropica, per scopi e funzioni variabili, da opere idrauliche
a insediamenti abitativi, cave sotterranee per l’estrazione di
materiali, luoghi di culto, ecc.
Il panorama complessivo appare pertanto notevolmente
complesso, e la valutazione della suscettibilità del territorio
pugliese a fenomeni di sprofondamento non può prescindere
da una attenta analisi della distribuzione e tipologia delle cavità
presenti. Partendo da tali considerazioni, da numerosi
anni il CNR-IRPI (Istituto di Ricerca per la Protezione Idrogeologica)
ha avviato programmi di ricerca finalizzati alla valutazione
della pericolosità naturale e antropica in ambiente
carsico. Le analisi relative a numerosi casi di studio, congiuntamente
a ricognizioni sull’intero territorio regionale, al fine
di individuare le situazioni maggiormente a rischio, hanno
consentito di raggiungere una notevole conoscenza dei fenomeni
di sprofondamento, e di avviare ricerche di tipo geologico-
geotecnico volte alla modellazione dei processi in atto,
ed alla valutazione della loro possibile evoluzione e degli effetti
sull’antropizzato sovrastante. Queste tematiche risultano
di interesse anche ai fini di Protezione Civile, come ripetutamente
dimostrato da molti episodi avvenuti nel corso degli
ultimi 15 anni, sino al caso più recente, verificatosi a Ginosa
nel gennaio 2014. Nella gran parte dei casi, le situazioni di
maggior pericolo sono connesse a cave abbandonate, ma
problematica appare anche la gestione di centri abitati caratterizzati
da elevata presenza di cavità sotterranee, in condizioni
frequenti di notevole degrado ed abbandono. Nel
contributo, oltre a fornire un quadro generale della situazione
sul territorio pugliese, incluso l’aggiornamento della cronologia
dei fenomeni di sprofondamento documentati, si presentano
i risultati delle ricerche in corso presso il CNR-IRPI,
a partire dai dati pugliesi del database cronologico dei fenomeni
di sinkholes alla scala nazionale
Management of water resources in karst environments, and negative effects of land use changes in the Murge area (Apulia)
No full textKarst hydrology is dominated by limited surface runoff, which represented the main problem
faced by man from the first historical phases of settlements. Man was however able to develop
techniques to collect the available water resources, and adapted his way of life to the karst environment,
reaching a sustainable use of the water resources. In the last centuries attention paid by man to
the need of the environment has dramatically changed, with immediate negative consequences. Several
anthropogenic actions have caused heavy changes in the natural landscape, with effects as increased
erosion and flash floods
Hypogea 2017
No full textFacendo seguito alla prima edizione di HYPOGEA 2015, svoltasi a Roma dall'11 al 17 marzo 2015, il Congresso Internazionale di Speleologia in Cavità Artificiali ha visto la sua seconda edizione finalmente realizzarsi in Turchia, nel magnifico scenario della Cappadocia. “Hypogea 2017”, ancora una volta organizzato sotto l'egida della International Union of Speleology e con il patrocinio (tra gli altri) della Società Speleologica Italiana, ha avuto una non facile fase di gestazione, legata inevitabilmente alla instabilità politica degli ultimi mesi
Il dissesto idrogeologico in ambiente carsico
No full textL’ambiente carsico presenta caratteristiche
intrinseche estremamente peculiari,
che lo differenziano da altri
ambienti naturali, e sono all’origine
della notevole fragilità e vulnerabilità di tali
territori. Il presente contributo descrive le
principali situazioni di dissesto idrogeologico
che possono verificarsi sul carso, evidenziando
i gravi danni che ne possono derivare, sia
in relazione all’antropizzato che insiste su
queste aree, che alle risorse naturale in esso
contenute. Si riportano pertanto alcuni casi di
sinkhole, movimenti gravitativi, eventi alluvionali,
oltre a situazioni di negativo impatto
ambientale derivanti da attività antropiche
su territori carsic
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