Nine years of spatial and temporal evolution of the La Valette landslide observed by SAR interferometry

The La Valette landslide located in the Ubaye valley (southern French Alps) has been investigated using 15 differential interferograms realized from ERS-1 and ERS-2 satellite radar images acquired between 1991 and 1999, both in 3-day cycle and TANDEM phase. Displacement values of the landslide have been deduced from the Synthetic Apenture Radan (SAR) interferometric products interpretation and compared with ground laser measurements. Four domains characterized by different velocity fields have been detected. Three of them can be distinguished from aerial photographs and field analysis. The slow velocity of a resistant bar located in the eastern side of the landslide has been detected on SAR interferograms. Between 1991 and 1996, changes in the landslide limits have been observed both in the upper and in the lower part; the changes have been caused by a retrogression of the main scarp and a down slope progression of the main body of the landslide, respectively. The average daily velocity of the landslide between 1991 and 1999 derived by interferometric analysis decreased from 1 to 0.4 cm/day, in agreement with ground-based measurements. A peak velocity of around 2 cm/day was observed in 1996. D 2002 Elsevier Science B.V. All rights reserved.

[1]  J. Locat,et al.  GLISSEMENT ET COULEE DE LA VALETTE DANS LES ALPES DE HAUTE-PROVENCE. PRESENTATION GENERALE ET MODELISATION DE LA COULEE , 1993 .

[2]  D. Massonnet,et al.  Deflation of Mount Etna monitored by spaceborne radar interferometry , 1995, Nature.

[3]  R. Goldstein,et al.  Satellite Radar Interferometry for Monitoring Ice Sheet Motion: Application to an Antarctic Ice Stream , 1993, Science.

[4]  K. Feigl,et al.  The displacement field of the Landers earthquake mapped by radar interferometry , 1993, Nature.

[5]  J. Rudant,et al.  Small displacements detected by SAR interferometry on the city of Paris (France) , 1999, IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS'99 (Cat. No.99CH36293).

[6]  R. Dikau,et al.  Monitoring Moderate Slope Movements (Landslides) in the Southern French Alps Using Differential SAR Interferometry , 2000 .

[7]  A. Giraud,et al.  Geological and geotechnical properties of the Terres Noires in southeastern France : weathering, erosion, solid transport and instability , 1995 .

[8]  Brice Martin,et al.  Landslides and climatic conditions in the Barcelonnette and Vars basins (Southern French Alps, France) , 1999 .

[9]  Charles Werner,et al.  On the derivation of coseismic displacement fields using differential radar interferometry: The Landers earthquake , 1994 .

[10]  Didier Massonnet,et al.  Two examples of the use of SAR interferometry on displacement fields of small spatial extent , 1996 .

[11]  Christophe Delacourt,et al.  Observation and modelling of the Saint-Étienne-de-Tinée landslide using SAR interferometry , 1996 .

[12]  C. Delacourt.  Détection et analyse de mouvements de surface par interféromètre différentielle , 1997 .

[13]  Bernd Scheuchl,et al.  Monitoring very slow slope movements by means of SAR interferometry: A case study from a mass waste above a reservoir in the Ötztal Alps, Austria , 1999 .