Remote sensing of volcanic impacts

In volcanology, remote sensing provides a global observation framework that is becoming increasingly valuable at multiple spatio-temporal scales. Satellite observations have improved monitoring for even the most remote volcanoes, provided a large-scale context to extrapolate field-based observations, and is now routinely used to characterize and monitor volcanic systems and their hazards. However, remote sensing remains underutilized to characterize volcanic impacts that result from the interaction of volcanic processes and societal assets. This chapter first provides a review of applications of remote sensing for impact assessment in volcanology, both in pre- and post-event contexts. Two case studies are used to illustrate the application of recent remote-sensing methods in impact assessments within the field of volcanology. First, the impact to the built environment caused by the 2014 eruption of Kelud volcano (Indonesia) is assessed using automated damage proxy maps produced from interferometric synthetic-aperture radar data. This automated approach is compared, validated and discussed against an impact assessment performed from the manual inspection of high-resolution satellite images. Second, Google Earth Engine is used to illustrate how simplified access to remote-sensing data offered by cloud-based platforms can provide a global and systematic framework to revisit the impacts of eruptions We illustrate the application of Google Earth Engine to various tasks, such as change detection and time series analyses, using the 2010 eruption of Merapi volcano (Indonesia). Very few volcanic impact assessments fully utilize remote sensing, but as such data become more easily available, stored and processed, there is the exciting potential for new methods and tools that can better capture, characterize and ultimately forecast volcanic impacts.