Analysis of Extreme Events in Geoelectrical Time Series Measured in a Seismic Area of Southern Appenine Chain (Italy)     

Luciano?TelescaEmail author  Marianna?Balasco  Gerardo?Colangelo  Vincenzo?Lapenna 《Natural Hazards》2005,34(2):177-198

In the present paper we analyse the series of extreme events in geoelectrical signals recorded at the monitoring station Tito located in a seismic area of southern Italy. Applying an objective criterion to estimate the probability of occurrence of extreme events in the time series (Cuomo et al., 1996; Cuomo et al., 1997), we found a correlation between the geoelectrical anomalies and earthquakes in the area monitored during the period of recording.  相似文献   

Structural setting and tectonic evolution of the Apennine Units of northern Calabria     

Alessandro Iannace  Glauco Bonardi  Marco D'Errico  Stefano Mazzoli  Vincenzo Perrone  Stefano Vitale 《Comptes Rendus Geoscience》2005,337(16):373

A new structural–stratigraphic synthesis of the Apennine units of northern Calabria is presented. The Meso-Cenozoic successions are grouped into two tectonic units, named Pollino–Ciagola Unit (PCU) and Lungro–Verbicaro Unit (LVU), comprising terrains formerly attributed to five different tectonic units. FeMg carpholite and blue amphibole record HP–LT metamorphism in the LVU, followed by progressive decompression leading to final greenschist facies re-equilibration during dominantly extensional deformation. Final tectonic emplacement of the LVU over the PCU post-dated the metamorphism of the LVU and was accompanied by intense ductile deformation along zones of strain localisation in footwall rocks. All of the units were later affected by folding and minor thrusting during subsequent Apennine tectonics. To cite this article: A. Iannace et al., C. R. Geoscience 337 (2005).  相似文献   

Thermal transformations in laser-heated chloritized annite     

C.?VitiEmail author  G. Di?Vincenzo  M.?Mellini 《Physics and Chemistry of Minerals》2004,31(2):92-101

Chloritized annite from the Irizar granite has been used for laser-heating experiments, following the procedures used for ⁴⁰Ar–³⁹Ar dating (heating steps in the 600–1080 °C temperature range). Four runs, at different temperatures, have been characterized using transmission electron microscopy, electron diffraction, micro-Raman and micro-IR spectroscopies. The water loss was evaluated by thermogravimetry. The chlorite domains break down first forming (001) amorphous layers, that later coalesce to rounded, equant inclusions and finally recrystallize to olivine and spinels plus silica glass. These phases occur within negative crystals hosted in ordered dehydrated annite, produced by dehydration and annealing of the starting annite. Dehydrated annite, olivine and spinels display topotactic relationships, determined by the common orientation of closely packed oxygen layers.  相似文献   

Modal model identification of structures under unmeasured seismic excitations     

Vincenzo Sepe  Danilo Capecchi  Maurizio De Angelis 《地震工程与结构动力学》2005,34(7):807-824

Techniques developed for structural identification of a structural model are typically based on information regarding the response and the forcing actions. However, in some situations it can be necessary, or simply useful, to refer only to the measured responses. In this paper we describe a technique suitable for identifying the modal model of a spatial frame in the frequency domain when the seismic input is unknown both in time contents and direction. In some previous theoretical works we established that this identification problem has a unique solution when at least three time‐history responses are known. Here numerical techniques are developed which allow the evaluation of the modal quantities in practice. Numerical applications are carried out on plane and spatial framed structures by using a modal model which may be complete, including all the structure's modes, or incomplete, including only the lowest modes. In most cases the obtained results are satisfactory. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Experiment of pumping at constant-head: an alternative possibility to the sustainable yield of a well     

Vincenzo Piscopo  Gianpietro Summa 《Hydrogeology Journal》2007,15(4):679-687

The effects of constant-head pumping on a well over a period of 1 year have been monitored and the results used in the research of a potential alternative for the attainment of sustainable yield. Sustainable yield is frequently related to the response of drawdown during a pumping test at constant-rate, which sometimes involves a difficult choice of conceptual model to be used to analyse the pumping results. The experiment, carried out on a well that taps a fractured aquifer in Italy, recorded the aquifer’s response to pumping, compared with the response of springs. From the trends in discharge variation with time, the period and magnitude of the recharge and the stored water volume at the beginning of the depletion period can be evaluated, and the discharge rate during the same depletion period can be predicted. A sustainable yield can be derived based on the water volume extracted during the depletion period rather than on the prediction of drawdown over a long time. The experiment also highlights the stability of water quality extracted from the well, and where this criterion is important, in some cases, the constant-head pumping can represent an alternative method of groundwater exploitation.  相似文献   

Measuring multifractality in seismic sequences   总被引：6，自引：0，他引：6  

Luciano Telesca  Vincenzo Lapenna 《Tectonophysics》2006,423(1-4):115

We investigated the multifractal structure of the interevent times between successive earthquakes that occurred in Umbria-Marche, which is one of the most seismically active areas of central Italy. We used the Multifractal Detrended Fluctuation Analysis (MF-DFA), which permits detection of multifractality in nonstationary series. Analyzing the time evolution of the multifractal behaviour of the seismic sequence, a loss of multifractality during the aftershocks is revealed.  相似文献   

The green–blue swing: plasticity of plankton food‐webs in response to coastal oceanographic dynamics          下载免费PDF全文

Domenico D'Alelio  Maria Grazia Mazzocchi  Marina Montresor  Diana Sarno  Adriana Zingone  Iole Di Capua  Gayantonia Franzè  Francesca Margiotta  Vincenzo Saggiomo  Maurizio Ribera d'Alcalà 《Marine Ecology》2015,36(4):1155-1170

The internal organization of plankton communities plays a key role in biogeochemical cycles and in the functioning of aquatic ecosystems. In this study, the structure of a marine plankton community (including both unicellular and multicellular organisms) was inferred by applying an ecological network approach to species abundances observed weekly at the long‐term ecological research station MareChiara (LTER‐MC) in the Gulf of Naples (Tyrrhenian Sea, Mediterranean Sea) in the summers of 2002–2009. Two distinct conditions, characterized by different combination of salinity and chlorophyll values, alternated at the site: one influenced by coastal waters, herein named ‘green’, and the other reflecting more offshore conditions, named ‘blue’. The green and blue ‘phases’ showed different keystone biological elements: namely, large diatoms and small‐sized flagellates, respectively. Several correlations amongst species belonging to different trophic groups were found in both phases (connectance ~0.30). In the green phase, several links between phytoplankton and mesozooplankton and within the latter were detected, suggesting matter flow from microbes up to carnivorous zooplankton. A microbial‐loop‐like sub‐web, including mixo‐ and heterotrophic dinoflagellates and ciliates, was present in the green phase, but it was relatively more important in the blue phase. The latter observation suggests a more intense cycling of matter at the microbial trophic level in the blue phase. These results show that different modes of ecological organization can emerge from relatively small changes in the composition of aquatic communities coping with environmental variability. This highlights a significant plasticity in the internal structure of plankton webs, which should be taken into account in predictions of the potential effects of climatic oscillations on aquatic ecosystems and biogeochemical cycles therein.  相似文献   

New insights on diapirism in the Adriatic Sea: the Tremiti salt structure (Apulia offshore,southeastern Italy)   总被引：1，自引：0，他引：1  

Vincenzo Festa  Gianvito Teofilo  Marcello Tropeano  Luisa Sabato  Luigi Spalluto 《地学学报》2014,26(3):169-178

The reinterpretation of public seismic profiles in the Adriatic offshore of Gargano (Apulia, southern Italy) allowed the detection of a kilometre‐scale salt‐anticline, the Tremiti diapir, within the larger Tremiti Structure. This anticline was generated by diapirism of Upper Triassic anhydrites within a thick Mesozoic to Quaternary sedimentary succession. Both internal stratal patterns and shapes of Plio‐Quaternary units, and the occurrence of an angular unconformity between early Tortonian and Pliocene rocks on the Tremiti Islands, suggest that halokinesis began during the late Miocene and is still active today. An ancient extensional SE‐dipping fault, cutting an older Mesozoic low‐amplitude anhydritic ridge, played an important role during salt mobilization, which was promoted by NW‐SE shortening. The diapir grew in the footwall of this fault, causing its upward propagation. In some places, the ancient fault served as a preferential channel for the upward migration of the anhydrites.  相似文献   

A deep-seated slow movement controlled by structural setting in marly formations of Central Italy   总被引：1，自引：1，他引：0  

Vincenzo Grana  Paolo Tommasi 《Landslides》2014,11(2):195-212

The site investigation of low-gradient slopes composed by marly rocks usually focuses on shallow slides in weathered mantling material as it is assumed that the underlying bedrock has higher strength, but deeper investigations may reveal larger, active, deep-seated movements. A typical example of this is found in Montemartano (Perugia, Central Italy). Here aerial photo interpretation and field observations indicate that active movements involve the shallower portion of the slope, formed by a very old and large landslide body extending over an area of about 0.5 km². Borehole core logging and probe inclinometer monitoring reveal that the area corresponding to the deep-seated landslide is moving at a maximum rate of 70 mm/year down to a maximum depth of 40 m. A comparison of inclinometer and piezometer data indicates that the movement seasonally reactivates even when rainfall and piezometer levels are below average values and suggests that structural setting of the whole slope influences both groundwater flow and movement kinematics. This hypothesis is reinforced by seepage analyses and stability analyses yielding a mobilized shear strength close to residual strength of the clayey interbeds of the marly limestone formations. This implies that instability occurs along bedding over a large part of the slide. The importance of these phenomena in land management policy is discussed and the critical aspects of their investigation and monitoring are addressed. The reconstruction of landslide geometry/stratigraphy and geotechnical characterization of the materials is closely considered, particularly as these are complicated by the limited representativeness of field and laboratory investigations in this type of material.  相似文献   

Comparison of pumping at constant head and at a constant rate for determining the sustainable yield of a well     

Antonella Baiocchi  Francesca Lotti  Simone M. Piacentini  Vincenzo Piscopo 《Environmental Earth Sciences》2014,72(4):989-996

Determining the yield of a production well remains one of the main problems in hydrogeological studies. Starting from the results of a 3-year-long monitoring of a continuously exploited well functioning at constant head (i.e., at a variable discharge rate), a new pumping style has been examined using numerical models. The objective is to control the impact of pumping on the aquifer in accordance with the principle of sustainability. Different models were developed in a transient state and were calibrated using discharge data of the well during the recession periods. Successively, the trends of the residual outflow from the aquifer system with the well operating at variable discharge and at constant discharge were simulated. The results indicate that the ratio of the volume of water pumped from the well to the volume of residual outflow is a significant indicator of the sustainability of groundwater withdrawals. Modeling confirms that a constant discharge rate can be derived from the information gained through a preliminary production phase of a well at constant head. This approach appears to be particularly useful when the problem is determining the sustainable yield of a single well from aquifers with low hydraulic diffusivity.  相似文献