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The present study gathers a large amount of both existing and unpublished biostratigraphic data, which allows a detailed and complete definition of the stratigraphic features of the late Oligocene–late Miocene Maltese Archipelago sedimentary succession, recording in turn the tectonic and eustatic history of the Central Mediterranean region. We selected five sections in the Malta Island and three in Gozo, representative of the entire sedimentary succession, affected by well-known erosional surfaces, correlated to low-stands of the sea level, often associated with phoshatic layers, linked to the subsequent high-stands. The sedimentary interval, and thus the associated hiatuses, was constrained both by the bio-chronostratigraphic attribution and by the comparison with the third-order succession of the New Jersey passive margin, which shows strict analogy with the geodynamic context in which the Maltese succession deposited. The diachroneity at the base of the formations in the different sections, and the presence of intraformational unconformity/hiatuses, highlighted the role of the tectonic, which depicted a complex sedimentary basin, characterized by more distal versus more marginal sectors. Furthermore, the possibility to compare the sedimentary succession with the oxygen isotope curve connects the sedimentation interruptions, recorded within the Maltese Archipelago deposits, to global cooling events.
相似文献A monitoring system is operative in the Peschiera Springs slope (Central Apennines, Italy) to mitigate the landslide risk related to the hosted main drainage plant of Rome aqueducts by providing alert warning. Such a strategy allows to avoid out-of-service episodes so reducing extra-costs of water distribution management. The Peschiera Springs slope is involved in a rock mass creep characterized by an average steady strain rate of 1 mm year−1 and responsible for several landforms including sinkholes, subvertical scarps and trenches. Moreover, an average aquifer discharge of 19 m3 s−1 causes an intense limestone dissolution concentrated in correspondence with release bands and discontinuities that dislodge the jointed rock mass. Since 2008, an accelerometric network has been operating within the slope; about 1300 microseismic local events were recorded up to now, distinguished in failures and collapses. A control index, based on frequency of occurrence and cumulative energy of the recorded microseismic events was defined to provide three levels of alert. In 2013, a temporary nanoseismic Seismic Navigation System (SNS) array was installed inside a tunnel of the drainage plant to integrate the pre-existent seismic monitoring system. This array allowed to record 37 microseismic events, which locations are in good agreement with the evolutionary geological model of the ongoing gravitational slope deformation. In 2014, a permanent nanoseismic SNS array was installed in the plant and allowed to record several sequences of underground collapses including more than 500 events. The nanoseismic monitoring system is allowing to: (1) increase the detection level of the monitoring system; (2) locate hypocentres of the events; and (3) detect precursors of the strongest events.
相似文献A novel procedure is proposed to analyse continuous seismic signal on hourly scales to have a prompt discrimination among the different sources. Specifically, this approach is applied to a massive dataset recorded at Campi Flegrei caldera during the year 2006 when a swarm of volcano-tectonic earthquakes occurred. The convolutive independent component analysis is adopted to obtain a clear separation among meteo-marine microseism, anthropogenic noise, hydrothermal tremor in the absence of volcano-tectonic activity, whereas in non-stationary conditions a contribution connected to the corner frequency of the earthquakes emerges. A coarse-grained variable to be monitored continuously is introduced, i.e. the frequency associated with the maximum amplitude of the power spectral density of the deconvolutive independent components. That parameter is sensitive to the variation in the frequency bands of interest (e.g. that corresponding to the corner frequencies of volcano-tectonic events) and can be used as marker of the insurgence of seismic activity.
相似文献The last few years have seen the debate on the geoethics of environmental and climatic protection growing to include resilience as a central idea within this new discipline, which holds many similarities with geography. Resilience analysis often looks at the capacity to re-establish conditions of equilibrium within a system which has been hit by a serious shock, e.g. a natural or man-made disaster. Geoethics works, in tandem with geological analyses and the geography of risk, to inform a population and develop integrated risk management in such a way as to strengthen a community’s resilience. The aim of this work is to study some people’s capacity to overcome what was potentially a disastrous event and, through a process of reconstruction, turn it into an occasion for growth. The experiment, carried out in the primary and middle schools in Aiello Calabro (Calabria, southern Italy), was conducted on the basis of the belief that there is a close relationship between a population’s having a realistic understanding of the risk of such an event, e.g. an earthquake, and high levels of resilience. We also tried to gain an insight into the relationship that may exist between resilience in primary and secondary school children and methods of coping which give an appropriate management of seismic risk. To be more precise, we try to discover whether there is a link between good/appropriate resilience and good/appropriate risk management.
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