Mass Movement

The Azores archipelago is exposed to different geological and meteorological hazards already responsible for thousands of deaths and severe damages. In order to detect precursory signals and develop early warning systems a multi-parametric monitoring network is under operation. Geophysical, geodetic, geochemical and meteorological independent techniques provide data that are integrated in the scope of a continuous hazard and risk assessment programme to support civil protection regional and local authorities.

The Tropical Rainfall Measuring Mission (TRMM), launched in 1997, uses active and passive microwave instruments to confirm the validity of tropical rainfall estimates derived from operational passive microwave sensors and provides a foundation for merging rainfall information from other satellites. High-resolution microwave information is important for fixing the locations of tropical cyclone tracks as well as establishing accurate initial positions to effectively forecast tropical cyclone progression. The TRMM Microwave Imager (TMI) is designed to “see” through clouds and provide high-resolution rainfall structure information within tropical cyclones. TRMM’s Precipitation Radar (PR) is designed to provide vertical structure information within tropical cyclones. Together, TRMM PR and TMI data have been used to establish key characteristics of the distribution and variability of rainfall in tropical cyclones and obtain insights into storm structure,…

A GPS monitoring system has been developed for the investigation of landslides. The applicability of this system is demonstrated by monitoring the deep-seated mass movement Gradenbach, Austria. 17 GPS surveys of at least 48 hours duration each were carried out during the last seven years. The motions can be determined with an accuracy of 4 mm in horizontal direction and 8 mm in vertical direction. The accurate GPS results suggest that the velocity pattern of the deep-seated mass movement at Gradenbach is not uniform but rather intermittent, i.e., highly accelerated motions are followed by periods of creeping. The causes for this pattern are unknown.
For the investigation of the mechanics of this phenomenon a strain rosette for in-situ measurements of local distance changes is being developed. It consists of three embedded extensometers at a separation in orientation of 120°. The sensors are long gauge (5 m) fibre optical…

The Agustin Codazzi Geographic Institute (IGAC) of Colombia and UNOOSA recently signed a cooperation agreement making IGAC the newest UN-SPIDER RSO. IGAC has been promoting the use of space-based information within Colombia for a variety of purposes and has also been supporting UN-SPIDER in activities conducted in Latin America and the Caribbean. As an RSO, IGAC will continue to provide support in terms of experts towards the provision of technical advisory support to countries within the region and will contribute to capacity building efforts in this region.

El Instituto Geográfico Agustín Codazzi (IGAC) de Colombia y UNOOSA firmaron en el año 2011 un acuerdo de cooperación para establecer la Oficina Regional de Apoyo en Colombia. IGAC promueve en Colombia el uso de información obtenida desde el espacio para distintos propósitos y ha apoyado a ONU-SPIDER en sus actividades conducidas en América Latina y el Caribe. Como Oficina Regional de Apoyo, IGAC continúa ofreciendo expertos a ONU-SPIDER para su Asesoría Técnica a países de la región con el objetivo de contribuir en los esfuerzos de fortalecimiento de capacidades en la región.

On 17 November 2000 a major landslide occurred on the slopes of Mount Mangart in the upper Posocje region, Slovenia, as a direct consequence of extreme rainfall and assortment of several inconvenient circumstances. A research group was established immediately after the event to find possible causes of the landslide and monitor its consequences. As a part of these attempts also remote sensing and integration of remotely sensed data to GIS was used. In the paper usefulness of satellite images as one of the most convenient data source in natural hazard observation is demonstrated. Satellite images were acquired within the “Space and Major Disaster” Charter, started just a few weeks before the event by the European Space Agency, the Centre National d’Etudes Spatiales and the Canadian Space Agency. Advanced image processing was performed carefully to analyze various aspects of the event. Before and after radar images were used to detect soil moisture and…

On 17 November 2000 a major landslide occurred on the slopes of Mount Mangart in the upper Posocje region, Slovenia, as a direct consequence of extreme rainfall and assortment of several inconvenient circumstances. A research group was established immediately after the event to find possible causes of the landslide and monitor its consequences. As a part of these attempts also remote sensing and integration of remotely sensed data to GIS was used. In the paper usefulness of satellite images as one of the most convenient data source in natural hazard observation is demonstrated. Satellite images were acquired within the “Space and Major Disaster” Charter, started just a few weeks before the event by the European Space Agency, the Centre National d’Etudes Spatiales and the Canadian Space Agency. Advanced image processing was performed carefully to analyze various aspects of the event. Before and after radar images were used to detect soil moisture and…

Landslides are severe environmental hazards in mountains areas. Nowadays, the threat of landslides to public safety has become more pronounced as a result of the burgeoning development in landslide-prone areas, the increase of deforestation in hilly areas, and the increase of regional precipitation caused by global climate change.
Traditional landslide risk assessment requires immense physical power to assemble different in-situ data such as identification of landslide location, land-cover classification and surface geometry. Such traditional data collection technique is very time consuming, and thus impossible to be applied for the regional scale assessment.
Remote sensing techniques, therefore, are the solutions for providing fast and up-to-data landslide assessments. This thesis focuses on the applications of multispectral remotely sensed data for landslide recognition and landslide prediction. Wollongong of Australia was chosen as a test bed for these…

This study investigates and demonstrates the state of the art in remote sensing techniques for detailed landslide hazard assessment applicable to large areas. Since the most common methods of landslide hazard assessment using simple inventories and weighted overlays are heavily dependent on three-dimensional terrain visualization and analysis, stereo satellite images from the IKONOS Very High Resolution (VHR) sensor are used for this study. The DEMs created from IKONOS stereo images appear to be much more accurate and sensitive to micro-scale terrain features than a DEM created from digital contour data with a 2 m contour interval. Pan-sharpened stereo IKONOS images permit interpretation of recent landslides as small as 2–3 m in width as well as relict landslides older than 50 years. A cost–benefit analysis comparing stereo air photo interpretation with stereo satellite image interpretation suggests that stereo satellite…

Collecting information on landslide occurrence and activity over wide areas is a crucial task for landslide hazard assessment. Field techniques, despite being very precise, are usually not sufficient to achieve this goal, since they mostly provide point-based measurements. Mainly because of its synoptic view and its capability for repetitive observations, optical (visible-infrared) remotely sensed imagery acquired at different dates and at high spatial resolution can be considered as an effective complementary tool for field techniques to derive such information. An image-processing method to map and monitor landslide activity using multitemporal optical imagery is proposed. The method entails automatic change detection of suitably pre-processed (geometrically registered and radiometrically normalised) sequential images, followed by thresholding into landslide-related change pixels. Subsequent filtering based on the degree of rectangularity of regions can also be…