Referenced polarization imaging for surface displacement measurements

1999 ◽  
Author(s):  
Laura J. Ulibarri ◽  
James K. Boger ◽  
Matthew P. Fetrow
Keyword(s):  
Surface Displacement ◽  
Polarization Imaging ◽  
Displacement Measurements

scholarly journals Time forecast of a break-off event from a hanging glacier

2016 ◽  
Vol 10 (3) ◽  
pp. 1191-1200 ◽  
Author(s):  
Jérome Faillettaz ◽  
Martin Funk ◽  
Marco Vagliasindi
Keyword(s):  
Real Time ◽  
Power Law ◽  
Surface Displacement ◽  
Early Warning Systems ◽  
Warning Systems ◽  
Safety Measures ◽  
Periodic Oscillations ◽  
Ice Volume ◽  
Surface Displacements ◽  
Displacement Measurements

Abstract. A cold hanging glacier located on the south face of the Grandes Jorasses (Mont Blanc, Italy) broke off on the 23 and 29 September 2014 with a total estimated ice volume of 105 000 m3. Thanks to accurate surface displacement measurements taken up to the final break-off, this event was successfully predicted 10 days in advance, enabling local authorities to take the necessary safety measures. The break-off event also confirmed that surface displacements experienced a power law acceleration along with superimposed log-periodic oscillations prior to the final rupture. This paper describes the methods used to achieve a satisfactory time forecast in real time and demonstrates, using a retrospective analysis, their potential for the development of early-warning systems in real time.

The surface velocity field in steep and breaking waves

1988 ◽  
Vol 189 ◽  
pp. 1-22 ◽  
Author(s):  
W. K. Melville ◽  
Ronald J. Rapp
Keyword(s):  
Water Waves ◽  
Surface Displacement ◽  
Breaking Waves ◽  
Surface Velocity ◽  
Breaking Wave ◽  
Laser Anemometry ◽  
Air Water Interface ◽  
Velocity Spectra ◽  
Displacement Measurements ◽  
Surface Drift

Coincident simultaneous measurements of the surface displacement and the horizontal velocity at the surface of steep and breaking waves are presented. The measurements involve a novel use of laser anemometry at the fluctuating air-water interface and clearly show the limitations of surface displacement measurements in characterizing steep and breaking wave fields. The measurements are used to examine the evolution of the surface drift velocity, spectra, wave envelopes, and forced long waves in unstable deep-water waves. Preliminary results of this work were reported by Melville & Rapp (1983).

Pavement displacement sensitivity to layer moduli

2002 ◽  
Vol 39 (6) ◽  
pp. 1395-1398
Author(s):  
Dieter Stolle
Keyword(s):  
Finite Element ◽  
Surface Displacement ◽  
Falling Weight Deflectometer ◽  
Contribution Ratio ◽  
Displacement Sensitivity ◽  
Stiffness Characteristics ◽  
Element Technique ◽  
Falling Weight ◽  
The Relationship ◽  
Displacement Measurements

The backcalculation of layer moduli using falling weight deflectometer data has proven to be challenging owing to the insensitivity of displacement measurements to the stiffness characteristics of some layers. This note describes a rigorous, yet simple, finite element technique for identifying the relationship between surface displacement and the elastic modulus of each layer. An example is given to demonstrate the application of the procedure.Key words: pavements, subgrade, backcalculation, contribution ratio.

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