Vernon Singhroy

Methods for Remote Engineering Geology Terrain Analysis in Boreal Forest Regions of Ontario, Canada

The Ontario Geological Survey and Canada Centre for Remote Sensing have developed methods for engineering geology terrain analysis using digital elevation models (DEMs) and remotely sensed imagery for remote areas within the boreal forest region of the Canadian Shield. Traditional methods of terrain analysis would be expensive because of the limited access and the vast area involved. Four main components of the terrain are considered: material, landform, relief, and regional drainage conditions. Landform (roughness) and relief are derived automatically from an analysis of a detailed hydrological-conditioned DEM. Regional drainage conditions are estimated from RADARSAT imagery with a mask based on the use of aspect and slope to limit the effects of topography on backscatter. Various types of analysis of LANDSAT imagery are then combined with all the above digital data layers to interpret material type. An automated method that first determines the relationships of the various layers of digital information in areas of known terrain conditions and then predicts terrain conditions in adjacent unmapped areas, is discussed.

Characterization of landslide deposits using SAR images

This paper provides some preliminary results of the use of RADARSAT fine mode image for characterizing the debris size and distribution of a 30/spl times/10/sup 6/ m/sup 3/ rock avalanche. From the image we were able to classify coarse, medium and fine debris based on their SAR texture. Such simple textural classification will be useful to plan more detail field and aerial surveys on large landslides so as to understand landslide processes, post failure mechanism and mobility.

Landslide risk assessment with high spatial resolution remote sensing satellite data

Landslide identification and mapping are essential for landslide risk and hazard assessment. This paper reports on the uses of remote sensing techniques for mapping landslide areas ranging in size from large to small. High-resolution stereo SAR and optical images are providing useful information for detailed mapping of large landslides, however mapping of smaller scale slides still requires extensive use of airphotos and fieldwork.

InSAR Monitoring of Permafrost Activity in the Lower Mackenzie Valley, Canada

The region of interest is located approximately in the downstream part of the Mackenzie River, Canada. Our study focuses on guidelines to process RADARSAT-1 interferometric C-band data in a permafrost environment and monitor permafrost activity and landslide motion over 18 month period. From the interferometric method (D-InSAR) on ~100 interferograms, the main conclusions are (1) a high resolution Digital Elevation Models (DEM) and a shorter satellite revisit time intervals are essential to ensure InSAR processing accuracy for small deformations associated with permafrost activity; (2) the permafrost has sustained several changes over a year of monitoring (thaw starting during end of April-mid of May, and freezing around mid October). The deformation peak is reached in the summer time between mid of May and July (up to 15 plusmn 2 mm). This method will provide a guideline for In SAR monitoring of similar areas in permafrost environment.

Terrain interpretation from SAR techniques

Our results have shown that selective processing of RADARSAT-1 images has assisted in regional terrain mapping of large areas the northern boreal forest region in Canada. Terrain roughness information derived from RADARSAT-1 when fused with high resolution DEM data provided image maps that are useful for landform interpretation.

Geological applications of RADARSAT-1: a review

Recent results have shown that RADARSAT-1 images have provided geologists with useful information. for mapping structure, geomorphology and rock units. This paper discusses the role of multi-incidence RADARSAT and data fusion techniques for geological mapping. The results of,several case studies, the guidelines for the selection-of the various RADARSAT-1 incidence angles for geological applications, and the use of stereo RADARSAT and visualization techniques for geohazard characterization, are presented.

High Resolution Rapid Revisit InSAR Monitoring of Surface Deformation

Abstract. This article provides temporal guidelines for the RADARSAT Constellation Mission (RCM) data acquisitions on several active high-risk surface deformation sites in Canada. The RCM will be tasked by several high-priority users and conflicts in acquisitions needed to be carefully resolved. Monitoring the deformation process on several representative sites, we can target our 4-day interferometric synthetic aperture radar (InSAR) acquisition plan for the future RCM. We provide examples of high-resolution (1–3 m) InSAR measurements for monitoring high-risk landslides affecting transportation and energy corridors, as well as surface deformation related to the steam injection process of extracting oil at the oil sands area. For all of these sites, we recommend specific temporal acquisition parameters for different deformation behaviors related to different landslide triggering mechanisms and oil extraction. The high-resolution InSAR images are effective in characterizing differential motion within these low-velocity landslides. Our results show that rapid revisit InSAR acquisitions are required during the combined wet spring and storm events for coastal landslides. Highly fractured slow-moving landslides along railway corridors require InSAR acquisitions throughout the year. Permafrost-triggered landslides affecting pipeline corridors require acquisitions during the peak summer thaw season. Deformation triggered by steam injection over the oil sands requires high-resolution constant rapid revisit monitoring during the steaming and extraction periods. Résumé. Cet article contient les directives temporelles d’acquisition de données pour la mission de la constellation Radarsat (la mission) au-dessus de différents sites canadiens à haut risque de déformation de surface active. La mission recevra des demandes de différents utilisateurs hautement prioritaires et les conflits relatifs à l’acquisition des données devront être résolus avec circonspection. Pour avoir surveillé le processus de déformation à différents sites représentatifs, nous pouvons cibler notre plan d’acquisition de données d’interférométrie SAR sur quatre jours pour la future mission. Nous donnons des exemples de mesures SAR à haute résolution (1 à 3 m) visant la surveillance de sites où prévaut un risque élevé de glissement de terrain qui pourrait endommager les corridors de transport et les couloirs de transport d’énergie, ainsi que les déformations de surface découlant de l’injection de vapeur dans le but d’extraire des hydrocarbures dans la région des sables bitumineux. Pour chacun de ces sites, nous recommandons des paramètres précis pour les temps d’acquisition en fonction des différents comportements de déformation liés aux différents mécanismes de déclenchement de glissement de terrain et d’extraction d’hydrocarbures. Les images d’interférométrie SAR à haute résolution caractérisent efficacement les mouvements différentiels dans ces glissements de terrain à faible vitesse. Nos résultats montrent que pour les glissements de terrain côtiers, il est nécessaire de faire l’acquisition par une réobservation rapprochée au cours des printemps humides jumelés à des événements pluvio-hydrologiques. La détection de lents glissements de terrain très fracturés, le long des voies ferrées exige des mesures d’interférométrie SAR tout au cours de l’année. Les glissements de terrain causés par le dégel du pergélisol qui affectent les corridors des pipelines exigent des mesures pendant la période de fonte estivale maximale. La déformation déclenchée par l’injection de vapeur dans les sables bitumineux exige une surveillance par des réobservations à haute résolution, fréquentes et constantes pendant les épisodes d’injection de vapeur et d’extraction d’hydrocarbures.

High Resolution InSAR Monitoring of Coastal Landslides

Radar interferometry (InSar) techniques using images from several radar satellites are increasingly being used in slope stability assessment. During the past year there were at least 25 media reports of landslides, some fatal, occurring in various areas in Canada. In this paper, we provide examples of using high resolution (3 m) InSAR techniques from RADARSAT and TerraSAR X to monitor coastal landslide affectiong transportation corridors. The high-resolution InSAR images are very effective in characterizing differential motion within these low velocity coastal landslides. The active wet spring periods are better monitored by the more frequent revisits from TerraSAR X.