Surface displacements of two landslides evaluated by GPS and inclinometer systems: a case study in Southern Apennines, Italy     

Stefano Calcaterra  Claudio Cesi  Caterina Di Maio  Piera Gambino  Katia Merli  Margherita Vallario  Roberto Vassallo 《Natural Hazards》2012,61(1):257-266

This paper reports experimental data on surface and deep displacements evaluated by means of GPS stations and inclinometers in two rototranslational deep landslides in a clayey slope of the Italian Southern Apennines. The displacements of the landslides cause continuous damage to buildings and infrastructures. To study these phenomena and control their effects, the local public administration provided financial support for a geotechnical investigation that started in 2004. Laboratory tests, in situ pore pressure and inclinometer measurements were carried out. In July 2006, systems of fixed-in-place inclinometer probes with continuous data acquisition were installed in two of the eleven guide casings, in correspondence to the slip surfaces detected by previous periodical measurements. In the meanwhile, a GPS network was installed, consisting in six permanent stations and ten non-permanent ones. Among the latter, five were installed on the top of five inclinometer casings. The experimental results show that, in the case under study, the surface displacements evaluated by means of the GPS stations are consistent with the surface displacements evaluated by means of the inclinometer measurements. This implies mutual data validation, availability of considerable amount of continuous data, as well as monitoring continuity when, for some reason, one of the instruments goes out of use.  相似文献   

Iī-I2/c phase transition in alkaline-earth feldspars along the CaAl2Si2O8-SrAl2Si2O8 join: Thermodynamic behaviour     

M. Tribaudino  P. Benna  E. Bruno 《Physics and Chemistry of Minerals》1993,20(4):221-227

Feldspars crystallized in the range SrF₈₀An₂₀-SrF₆₀An₄₀ of the join CaAl₂Si₂O₈-SrAl-₂Si₂O₈ from gels at T = 1350–1500° C for short time show cell parameters significantly different from those obtained from longer heating. This difference has been interpreted as due to higher metastable Al/Si disorder in short heated samples and to more ordered configurations with longer heat treatments. HT powder spectra show that the T _c of the Iī-I2/c phase transition of feldspars changes with composition and with the degree of order at constant composition; the evolution of the spontaneous strain (～cosα^*) versus T for the samples examined shows a variation in the order of the transition from continuous (II order) in more ordered and Sr-rich samples to a discontinuous behaviour (presumably I order) for more disordered and Sr-poor samples. A biquadratic coupling between displacive and OD parameters is therefore suggested.  相似文献   

Structural modifications in clinopyroxene solid solutions: The Ca-Mg and Ca-Sr substitutions in the diopside structure     

Piera Benna  G. Chiari  E. Bruno 《Mineralogy and Petrology》1987,36(1):71-84

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High pressure behaviour of lead feldspar (PbAl2Si2O8)     

M. Tribaudino  P. Benna  E. Bruno  M. Hanfland 《Physics and Chemistry of Minerals》1999,26(5):367-374

An in situ high pressure powder diffraction study, using high-brilliance synchrotron radiation, on lead feldspar (PbAl₂Si₂O₈) was performed. Two samples, with Q _od=0.68 and 0.76, were loaded in a diamond anvil cell and were compressed up to 11 GPa. Up to P=7.1 GPa the only phase present is lead feldspar. In the range 7.1–9.4 GPa sudden changes in the position of the reflections suggest the transformation of lead feldspar to a new phase (probably feldspar-like). The absence of split that would be compatible with triclinic symmetry rules out the monoclinic-triclinic transition, that was reported for the structurally similar strontium feldspar. At P>9.4 GPa some new extra reflections not indexable in the feldspar cell are present as well. During decompression the lead feldspar was the only phase present at P<6 GPa. Peak enlargement was observed with pressure, probably preliminary to amorphization. However almost complete amorphization was observed only after fortuitous shock compression at ∼18 GPa; the crystallinity was recovered at room pressure after decompression. The bulk modulus for lead feldspar was K=71.0(9) and 67.6(1.2) GPa for the two samples, in the range reported for feldspars. The cell parameters show a compression pattern which is similar to that observed in anorthite, with Δa/a ₀>Δc/c ₀>Δb/b ₀; comparison with the high temperature behaviour shows that for lead feldspar the strain tensor with pressure is more isotropic and the deformation along a is less prominent. A turnover in the behaviour of the β angle with pressure suggests a change in the compression behaviour at P∼2 GPa. Rietveld refinement of the Pb coordinates was performed in a series of spectra with pressure ranging from 0.6 to 6.5 GPa. The combined analysis of cell parameters and Pb coordinates with pressure showed that the compression of the structure is mainly achieved by an approach of Pb atoms along a *. Received: 21 July 1998 / Revised, accepted: 13 October 1998  相似文献