104 research outputs found
Loss of life risk due to impacts of boulders on vehicles traveling along a very busy road.
The paper is aimed to describe the used approach for calculating the risk along a road stretch belonging to a very busy coastal road in Southern Italy. During the time span 1969-2013, 22 rockfalls affecting this road were inventoried. On 18th February 2014 a new rockfall happened and several boulders reached the northern lane of the road. On the basis of collected data concerning the landslide hazard and road vulnerability, a procedure for the probability evaluation of a fatal accident - for a road user - is presented, discussed in details and compared. The analysis is meant to allow the design of appropriate protection devices along the cliffs overhanging the road
Comparison between qualitative rockfall risk rating systems for a road affected by high traffic intensity
Abstract. The paper deals with the assessment of the rockfall risk for a road stretch, in southern Italy, affected by high traffic intensity. Three qualitative rockfall risk rating systems (QRSs) which use an exponential scoring with a base of 3 were employed, and then the results were compared. The used methods are the following: the Rockfall Hazard Rating System, a modified version of this method already proposed in the past by one of the authors, and the modified version of the Colorado Rockfall Hazard Rating System. The studied road stretch is about 11 km in length and is part of a very tortuous road flanked by rock slopes characterised by complex geostructural and geomechanical layouts. The road was subdivided into 56 sections, defined so as to have – as much as possible – homogeneous geological characteristics. By means of the three QRSs, it was possible to ascertain that high levels of rockfall risks are due to the lack of ditches, a very limited percentage of decision sight distance (PDSD) values and a small roadway width, whereas a subordinate factor is the hazard caused by rockfalls. Several positive and negative aspects arising from the use of the employed methods are highlighted and discussed.</p
Space-time gravity variations to look deep into the southern flank of Etna volcano
A microgravity 14-year-long data set (October 1994 - September 2007) recorded along a 24-kilometer East-West trending profile of 19 stations was analyzed to detect underground mass redistributions related to the volcanic activity involving the southern flank of Mt Etna volcano (Italy). A multiresolution wavelet analysis was applied to separate the volcano-related signal from the unwanted components due to mainly instrumental, human-made and seasonal effects. The residual space-time image evidenced two complete gravity increase/decrease cycles mainly affecting the central and eastern stations of the profile. The first gravity increase (early-1995 to end-1996) – decrease (end-1996 to late-1998) cycle reached a maximum amplitude of approximately 90 µGal. The second gravity increase (mid-1999 to mid-2000) – decrease (mid-2000 to early-2004) cycle attained an amplitude of about 80 µGal peak-to-peak. After about five years of a persistent negative gravity anomaly, a new semi-cycle started at the end of 2006 and continued during the last survey carried out in September 2007. We modeled the 1994-2007 gravity anomalies using a Quadratic Programming algorithm to infer the position and the evolution of the sources beneath the profile. The computed positive mass variations of about 1.05 x 1011 kg were interpreted as magma accumulation, while negative mass changes of about -1.20 x 1011 kg could reflect either magma migration or opening of new voids by tectonic tensile stresses within a source volume, where tensional earthquakes occurred
Geomagnetic survey of Italy. Repeat station network and magnetic maps: a short report
Starting in 1977, two geomagnetic project were undertaken in the frame of the >of the Consiglio Nazionale delle Ricerche(Project>of the National Research Council);1)a new national network of repeat stations for total field F, horizontal component H, vertical component Z, declination D.2)a 2nd order network of stations for F,Z,H to produce geomagnetic maps of Italy. The two projects were carried out by a > made up of Operating Units from Institutions to which the authors belong. The field work ended in 1981. The Istituto Nazionale di Geofisica coordinated the operations for both projects. This paper is intended to give a short report to the international scientific community on this work which has so far only appeared in the Italian literature.Published365-3681A. Geomagnetismo e PaleomagnetismoN/A or not JC
Extended Glasgow Outcome Scale to Evaluate the Functional Impairment of Patients With Subcortical Band Heterotopia: A Multicentric Cross-sectional Study
Background: Subcortical band heterotopia (SBH) is a rare malformation of the cortical development characterized by a heterotopic band of gray matter between cortex and ventricles. The clinical presentation typically includes intellectual disability and epilepsy. Purpose: To evaluate if the Extended Glasgow Outcome Scale-pediatric version (EGOS-ped) is a feasible tool for evaluating the functional disability of patients with (SBH). Method: Cross-sectional multicenter study of a cohort of 49 patients with SBH (female n = 30, 61%), recruited from 23 Italian centers. Results: Thirty-nine of 49 (80%) cases showed high functional disability at EGOS-ped assessment. In the poor result subgroup (EGOS-ped >3) motor deficit, language impairment, and lower intelligence quotient were more frequent (P < 0.001, P = 0.02, and P = 0.01, respectively); the age at epilepsy onset was remarkably lower (P < 0.001); and the prevalence of epileptic encephalopathy (West syndrome or Lennox-Gastaut-like encephalopathy) was higher (P = 0.04). The thickness and the extension of the heterotopic band were associated with EGOS-ped score (P < 0.01 and P = 0.02). Pachygyria was found exclusively among patients with poor outcome (P < 0.01). Conclusions: The EGOS-ped proved to be a reliable tool for stratifying the functional disability of patients with SBH. According to this score, patients could be dichotomized: group 1 (80%) is characterized by a poor overall functionality with early epilepsy onset, thick heterotopic band, and pachygyria, whereas group 2 (20%) is characterized by a good overall functionality with later epilepsy onset and thinner heterotopic band
Geomagnetic survey of Italy at 1979.0 Repeat station network and magnetic maps
attached an anomaly map for FA national network of 106 repeat stations for total field F, horizontal component H, vertical component Z and declination D has been undertaken in the frame of the 'Progetto Finalizzato Geodinamica' of the Consiglio Nazionale delle Ricerche. From the observed magnetic elements the repeat station values were referred to 1979.0 and five normal fields in the form of a 2nd order polynomial in latitude and longitude were computed: GDN for the whole Italian area, GDN-N for the northern Italy, GDN_C for central Italy, GDN-S for the southern Italy and GDN-Sn for Sardinia. From comparisons made on F between GDN and two planetary reference fields it has concluded that for total field the polynomial form can be well considered as representative of the main field in the Italian area. A 2nd order network of 2500 stations for F, Z, H, has been undertaken to produce geomagnetic maps of Italy. An anomaly map for F referred to the GDN normal field has been drawn. The main features of anomalies configuration are described.Published1-171A. Geomagnetismo e PaleomagnetismoN/A or not JC
Stress, strain and mass changes at Mt. Etna during the period between the 1991–93 and 2001 flank eruptions
During the ~8-year period between the 1991–93 and 2001 flank eruptions, the eruptive activity of Mt. Etna was confined to the summit craters. Deformation and tomography studies indicate that this activity was fed by a magma accumulation zone centered NE of the summit, at a depth of 5 to 9 km below sea level. The most significant gravity changes measured during the same period were induced by mass redistributions at shallower depth below the southeastern flank of the volcano, where minor ground deformation was observed (i.e., vertical displacements within 2 cm).
The mismatch between the position of pressure and mass sources is difficult to explain under the assumption that both are directly related to magma dynamics. Past studies have suggested that the gravity changes observed during 1994–2001 may primarily reflect changes in the rate of microfracturing along the NNW–SSE fracture/weakness zone (FWZ) that crosses the SE slope of Etna.
We use the finite element method to shed new light on the complex relations between stress, strain and mass changes that occurred at Etna during the studied period. In particular, following previous results on the degradation of the mechanical properties of rocks, we perform a set of simulations assuming that the part of the medium containing the FWZ is characterized by a lower Young's modulus than would be expected from interpolation of tomographic data. We find that the presence of the FWZ creates a distortion of the displacement field induced by the deeper pressure source, locally resulting in a weak extensional regime. This finding supports the hypothesis of a cause–effect relationship between pressurization beneath the NW flank and tensile extension beneath the SE slope of the volcano. We propose that this extensional regime enhanced the propagation of pressurized gas, that, in turn, amplified the tensile strain across the FWZ.
We also find that decreasing the value of Young's modulus in the FWZ allows for a larger amount of extension at depth, with no change in the magnitude of surface displacements. This result provides an indication of how the changes in the rate of microfracturing at depth, which are needed to induce the observed gravity changes, might have occurred without large ground deformation
Continuous dynamic response along a pre-existing structural discontinuity induced by the 2001 eruption at Mt. Etna
The intrusive process of the 2001 Mt. Etna eruption was accompanied by marked ground deformation and relevant seismic activity recorded between 12 and 17 of July (INGV-CT, 2001). At the same time, extensometer data evidenced the re-activation of a dry surface failure zone on the high south-eastern sector of Mt. Etna; this fracture system, formed in 1989, has been related to the propagation of a shallow blade-like dike along a NNESSW discontinuity (Bonaccorso and Davis, 1993; Bianco et al., 1998). The NNW-SSE discontinuity represents a complex low cohesion structure in which deformation may concentrate. Displacement measurements recorded on the surface fracture and the constraints obtained from seismicity show that the intrusion phase of the 2001 eruption has forced the NNE-SSW structure to move continuously with prevalent left-lateral displacement from a depth of 2–2.5 km b. s. l. to the surface with a compositive slip of about 3–5 centimeters.Published56/ (2004)ope
Coupled use of COSPEC and satellite measurements to define the volumetric balance during effusive eruptions at Mt. Etna, Italy
Global Value Chains and Deep Preferential Trade Agreements: Promoting Trade at the Cost of Domestic Policy Autonomy?
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