AlOS-PalSAR data for Geological Mapping and Landslide Monitoring
Vernon Singhroy(1), Goran Pavic(1) and Pierre-Jean Alasset(1)
(1) Canada Centre for Remote Sensing, Natural Resources Canada, 588 Booth Street, Ottawa ON K1A 0Y7, Canada
InSAR techniques are increasingly being used in slope stability assessment. Our research has shown that differential InSAR techniques are useful to monitor landslide activity along strategic transportation and energy corridors. The Mackenzie Valley in northern Canada is experiencing one of the highest rates on mean annual air temperature for any region in Canada, thereby triggering melting in the permafrost, which results in active layer detachment landslides. There are approximately 2000 landslides along the proposed Mackenzie Valley pipeline route. .The Mackenzie valley pipeline will traverse a 1300 km corridor, aimed at delivering natural gas to markets in southern Canada and United States. The pipeline - when completed - is estimated to cost $ 7 billion. In addition, the Trans Canada Highway in the Canadian Rockies are affected by several rock avalanches and slow retrogressive slides.
Our investigation has shown that differential InSAR are providing a useful monitoring technique for landslide activity under different slope, moisture and lithological conditions. The series of RADARSAT-1 InSAR images indicate the different level of activity of the slopes (large and small) during different periods of the year. RADARSAT-2 Terra SAR X are providing the high resolution rapid revisit capabilities needed to continuously monitor these active slopes along Canadian strategic energy and transportation corridors.
ALOS PALSAR InSAR results show that we can observe deformation on both vegetated and exposed rock areas on the Frank Slide. The Frank Slide, a 30 x 106 m3 rockslide-avalanche of Paleozoic limestone, occurred in April 1903 on the east face of Turtle Mountain of southern Alberta, Canada. Seventy fatalities were recorded. This slide is still active. In this study, we compare differential InSAR results from RADARSAT and ALOS PALSAR images over the near same time period during summer 2006 and 2007. The RADARSAT-1 InSAR results show that Frank Slide is relatively stable except for a small area on the North Slope. The ALOS data show a larger area of rock deformation on the same area. The ALOS PALSAR data show deformation not only on the exposed rocky surfaces but also on the vegetated South Peak of Frank Slide. This is particularly interesting since the South Peak is extensively monitored by in-situ sensors and does show gradual motion.
In the Sudbury Basin, where detailed geological mapping is supporting mineral exploration programs, our results show that there is no significant difference between RADARSAT and ALOS PALSAR images for the identification of exposed geological structures and dykes, as well as lithological contacts and units in these vegetated mineral belts. The vegetation penetration capability of the ALOS L band did not add any new litho-structural information, not seen by RADARSAT.
Keywords: InSAR, landslides, ALOS, Geological Mapping