1,721,609 research outputs found
East-West Trade and the Technology Gap - A Political and Economic Appraisal, édité par Stanislaw Wasowski
No full textZaleski Eugène. East-West Trade and the Technology Gap - A Political and Economic Appraisal, édité par Stanislaw Wasowski. In: Revue d'études comparatives Est-Ouest, vol. 7, 1976, n°3. pp. 245-252
Landslide activity maps for landslide hazard evaluation: Three case studies from Southern Italy
No full textThis paper focuses on the application of landslide activity maps for evaluating the mass movement hazard in selected areas of the Southern Apennines of Italy: Bisaccia, Calitri, and Buoninventre. The availability of multi-year aerial photo coverage helped to assess the morphological changes which occurred in the last 40 years. This information, integrated with historical data on slope instability and field checks, were used to produce landslide activity maps. These maps represent a short-cut in the assessment of mass movement hazard, because they focus on the effects of slope instability rather than on the causative conditions and processes; however, if kept simple and prepared at large scale, they may help the local administrators and land-use planners to reduce the socio-economic costs of landslides. Furthermore, the comparative study of landslide activity represents a relatively inexpensive and quick method for evaluating the performance of the engineering control efforts. The quantification of landslide activity in terms of areal frequency can represent an additional step, useful to determine the relative landslide hazard (zonation in more or less hazardous areas). For example, the estimates of areal frequency of active landsliding for the last 40 years demonstrated the great influence of the 1980 Irpinia earthquake (M(s) = 6.9) on the stability of slopes situated close to its epicenter (within a radius of about 20 km)
Advances and problems in understanding the seismic response of potentially unstable slopes
No full textThe influence of site effects on landslide triggering during earthquakes has been inferred in several studies,
but its evaluation is made difficult by the complexity of factors controlling the dynamic response of potentially
unstable slopes and also by the lack of local ground motion instrumental observations. This work explores this
problem and reports new findings based on an ongoing long term accelerometric monitoring conducted on a
landslide-prone test area in the Apennine Mountains, Italy, where the presence of site effects enhancing
seismic susceptibility of local slopes has been invoked on the basis of historic accounts of landsliding triggered
at large epicentral distance. The recordings relative to low-to-moderate magnitude earthquakes showed
significant amplifications affecting hillslope portions covered by thick (N5 m) colluvia and pronounced
amplification maxima oriented along the local maximum slope direction on a recent deep-seated landslide.
While the amplifications seem most likely linked to high impedance contrast between surface materials and
underlying substratum, the causes of directivity are less clear. The case of the monitored test site together
with evidence of site response directivity identified on other hillslopes, suggest that the directivity
phenomena can result from a combination of topographic, lithological and structural factors that act together
to re-distribute shaking energy, focusing it on site-specific directions. Thus, it is difficult to single out the
critical factors controlling such phenomena and no general criterion for the identification of sites affected by
directivity is proposed here. Nevertheless, the presence and orientation of site response directivity can be
revealed through reconnaissance techniques by using recordings of seismic weak motion and/or ambient
microtremors, and calculating azimuthal variation of shaking energy and horizontal-to-vertical ground
motion spectral ratios. A comparison with the recordings obtained during the recent MW=6.3 earthquake
that hit the Abruzzo region in April 2009 demonstrated that analysis relying on data from low energy events
can furnish valid indications for slope behaviour also under stronger shaking, provided the data are well
differentiated in terms of distance, azimuth and source characteristics. Furthermore, the comparative analysis
of the Abruzzo earthquake recordings at a landslide and reference sites showed that directivity properties of
strong shaking had been correctly anticipated using earlier weak motion observations. However, under the
complex slope conditions the identification of resonance frequencies from horizontal-to-vertical spectral
ratios estimated from weak-motion accelerometric recordings does not seem reliable, and better results have been obtained by velocimetric microtremor recordings
A song about a song according to Jerzy Wasowski and Jeremi Przybora
No full textAmong numerous songs written by Wasowski and Przybora for the tv and radio show
Old Gentlemen’s Cabaret two: Piosenka jest dobra na wszystko (A Song is a Universal Remedy)
from the Fifth Evening of the Cabaret (14 May 1960) and Mambo Spinoza from the Eighth
Evening (4 November 1961) might be considered autothematic. They represent an idea of
‘a song about a song’ — a common theme or motif in Polish popular music. In reaction to
ideological degeneration of different forms of mass entertainment between 1949 and
1955 (the period known as Stalinism), Wasowski and Przybora decided to ‘redefine’ a
song, writing these two pieces full of humour and allusions.Publikacja dofinansowana przez Wydział Filologiczny U
Time probabilistic evaluation of seismically-induced landslide hazard in Irpinia (Southern Italy)
No full textA recently proposed method, which incorporates the Newmark model to evaluate the earthquake-induced landslide hazard at regional scale, was applied to Irpinia, one of the most seismically active regions of Italy. The method adopts a probabilistic approach to calculate values of critical acceleration ac representing the minimum strength required for a slope not to fail at a fixed probability level in a given time interval. Regional probabilistic hazard maps were generated for the two failure types most common in Irpinia (slump-earthflows and rock falls). The results suggest that quite moderate critical acceleration (0.05-0.08 g) could suffice to keep the slope failure probability low. However, the available data indicate that potential slide surfaces with ac below these values could be common in Irpinia, where, perhaps in relation to particular geo-environmental conditions, a relative large number of marginally stable slopes might survive other destabilising actions and fail even on occasion of not particularly strong earthquake shaking
Developments in ambient noise analysis for the characterization of dynamic response of slopes to seismic shaking
Full text linkIn the last few decades, we have witnessed a growing awareness of the role of site dynamic response to seismic shaking in slope failures during earthquakes. Considering the time and costs involved in acquiring accelerometer data on landslide prone slopes, the analysis of ambient noise offers a profitable investigative alternative. Standard procedures of ambient noise analysis, according to the technique known as HVNR or Nakamura’s method, were originally devised to interpret data under simple site conditions similar to 1D layering (flat horizontal layering infinitely extended). In such cases, conditions of site amplification, characterized by a strong impedance contrast between a soft surface layer and a stiff bedrock, result in a single pronounced isotropic maximum of spectral ratios between horizontal and vertical component of ambient noise. However, previous studies have shown that the dynamic response of slopes affected by landslides is rather complex, being characterized by multiple resonance peaks with directional variability, thus, the use of standard techniques can encounter difficulties in providing reliable information. A new approach of data analysis has recently been proposed to exploit the potential of information content of Rayleigh waves present in ambient noise, with regard to the identification of frequency and orientation of directional resonance. By exploiting ground motion ellipticity this approach can also provide information on vertical distribution of S-wave velocity, which controls site amplification factors. The method, based on the identification of Rayleigh wave packets from instantaneous polarization properties of ambient noise, was first tested using synthetic signals in order to optimize the data processing system. Then the improved processing scheme is adopted to re-process and re-interpret the ambient noise data acquired on landslide prone slopes around Caramanico Terme (central Italy), at sites monitored also with accelerometer stations. The comparison of ambient noise analysis results with the outcomes of accelerometer monitoring reveals potential and limits of the new method for the investigations on slope dynamic response
Preface: Special issue from the symposia on remote sensing and ground-based geophysical techniques for recognition, characterisation and monitoring of unstable slopes
No full textEvaluating seismically-induced mass movement hazard in Caramanico Terme (Italy)
No full textMass movements and earthquakes represent two major geological hazards in the municipal territory of Caramanico Terme (south-central Apennines). Available records revealed the contemporaneous occurrence of earthquakes and slope failures on four occasions in the last four centuries (1627, 1706, 1933, and 1984). These events, with local intensities ranging from VI to IX, generated mass movements varying from a rotational slope failure to rock/block falls. All occurred in the southern periphery of the town and involved a thick carbonate megabreccia caprock and coarse colluvia which overlie a clayey substratum. Field investigation and review of historical records helped to delimit the areas susceptible to seismically triggered rockfalls. The mapping of historic and pre-historic rockfall deposits revealed their dispersal patterns and provided the basis for a determination of potential hazard zones. We approximate the temporal hazard assessment by relating the rockfall occurrence to the probability of earthquake triggering. Considering the VI degree triggering threshold indicated by local historical data, the statistical analysis of the regional seismic activity shows that events capable of inducing rockfalls have an approximately decennial recurrence in Caramanico. The approach presented could be readily applied to other potential risk areas of Italy by exploiting the rich long-term record of historical seismicity. In general, temporal hazard estimates at relatively low intensity levels will be possible even where the seismic history of the site is only well documented for a relatively limited time interval, provided that this interval is much longer than the recurrence time of the events exceeding the threshold considered
Risposta di sito in un’area franosa: osservazioni accelerometriche a Caramanico Terme (PE)
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