Present day and future remote sensing data. Report on globally available present-day and future remote sensing data and products. Report for EU-FP7-Projekt SENSUM (FP7-SPACE-2012-1/312972)

Kurzfassung

In terms of an integrative and comprehensive risk analysis, the issue of an appropriate data collection is widely recognized. In this context, remote sensing is generally perceived as a promising tool for an economical, up-to-date and independent data collection and has been employed in various investigations in the geo-risk context. A review of past applications reveals the versatility of remote sensing data and techniques with regard to the analysis of earthquake and landslide risks. The study of earthquake hazard components reach from geologic site characterisations and fault mapping, detection of pre-event surface temperature anomalies for early warning, kinematics and dynamics of active fault systems, to the detection of earthquake-induced changes to the land surface. For landslides, remote sensing techniques and applications contribute to basic terrain analysis including monitoring of slope stability and land cover, the detection and mapping of pre-event landslide-related activities such as slow mass movements as well as the volumetric quantification of landslide related changes to land cover and form. Remote sensing for vulnerability-centred investigations is a less long established field of research. Nevertheless, a vast amount of research aims at the derivation of pre-event vulnerability indicators – related to physical, demographic and socioeconomic aspects of vulnerability–. Also work on post-event emergency response and damage assessment employing especially very high resolution data has been carried out. In the context of geo-risk analysis, both for pre- and post-event as well as hazard- and vulnerability-centred investigations, past- and present-day remote sensing missions have proven useful. Data with a coarser geometric resolution and larger spatial coverage per scene are able to contribute to overall evaluation of pre- and post-event situations. In contrast, it is yet both difficult and expensive to obtain high geometric resolution data such as airborne LIDAR or VHR optical data over larger areas affected, specifically in case of an earthquake event. In addition to that, the geometric resolution of the sensors and the associated scene size and thus, the spatial scale of analysis, need always be selected in consideration of the context of the objects to be analysed. Future earth observation missions have the potential to play a key role in earthquake- and landslide-related investigations and to continue or even improve geoinformation products. For example, the ESA Sentinel missions will feature enhanced geometric and thematic capabilities and increased revisit capabilities at low cost. Other future missions such as ALOS-2, the RADARSAT constellation, DESDynI, CARTOSAT-3, ALOS-3, TerraSAR-X 2, TanDEM-L, WorldView-3, or the hyperspectral sensors EnMAP and HyspIRI still need to be assessed in terms of cost and applicability with respect to the particular research questions addressed. For example, TanDEM-L will open up opportunities to better understand the earth’s dynamic surface processes enabling continuous monitoring of earth surface deformation e.g. due to seismic movements, volcanic eruptions, landslides, subsidence or uplift in the range of centimetres. In this context, the enhanced capabilities of the described missions are believed to enable a leap forward in earthquake and landslide risk research both for hazard- as well as vulnerability-related investigations. Apart from the future perspective, international research groups from both government and academia have produced remote sensing based geo-products in past years that will provide valuable input to vulnerability-related research in the context of this project. These include on the one hand large area global or regional land cover datasets that can be used as a first approximation of human and physical exposure as well as for the disaggregation of population census data. However, with regard to these products, a better understanding of each data set’s strength and weakness is still on demand. On the other hand, space-based pre-operational emergency response services have produced a large product portfolio and significant experiences in post-event mapping applications in recent years. Overall, from a technical perspective, the constantly increasing availability and accessibil-ity of modern-day remote sensing technologies and the enhanced technical capabilities of future missions will provide new opportunities and data continuity for a wide range of geo-risk investigations. However, still today and in the future, data cost will be the main limiting factor.