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Titel |
Seismic site response of unstable steep slope using noise measurements: the case study of Xemxija Bay area, Malta |
VerfasserIn |
F. Panzera, S. D'Amico, A. Lotteri, P. Galea, G. Lombardo |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1561-8633
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Digitales Dokument |
URL |
Erschienen |
In: Natural Hazards and Earth System Science ; 12, no. 11 ; Nr. 12, no. 11 (2012-11-21), S.3421-3431 |
Datensatznummer |
250011199
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Publikation (Nr.) |
copernicus.org/nhess-12-3421-2012.pdf |
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Zusammenfassung |
Landslide phenomena involve the northern coast of Malta, affecting in
particular the urban area of Xemxija. Limestones overlying a clayey
formation represent the shallower lithotypes that characterize the
surficial geology of this area, where lateral spreading phenomena and
rockfalls take place.
Ambient noise records, processed through spectral ratio techniques, were
analysed in order to characterize the dynamic behavior of the rock masses
affected by the presence of fractures linked to the landslide body existing
in the area. Experimental spectral ratios were also calculated after
rotating the horizontal components of the seismic signal, and a direct
estimate of the polarization angle was also performed in order to
investigate the existence of directional effects in the ground motion.
The results of the morphologic survey confirmed the existence of large
cliff-parallel fractures that cause cliff-edge and unstable boulder
collapses. Such phenomena appear connected to the presence, inside the clay
formation, of a sliding surface that was identified through the
interpretation of the noise measurement data. The boundaries of the
landslide area appear quite well defined by the pronounced polarization
effects, trending in the northeastern direction, observed in the fractured
zone and in the landslide body in particular. |
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