Katy Burrows: LL 28.03.24

Resolving the impacts of earthquakes, storms, and prolonged rainfall on shallow landsliding
Abstract: In mountainous areas, earthquakes and rainfall trigger shallow landslides, which represent a significant source of erosion, as well as posing a hazard to communities. Multi-spectral satellite images allow us to compile detailed inventories of these events which allow us to estimate mass wasting volumes and calibrate landslide models. Unfortunately, these images are often obscured by cloud cover so that landslides are mapped using images acquired weeks or months after they were triggered. For landslides triggered during sequences of earthquakes or storms, or during long periods of rainfall, this means we cannot tell when each landslide happened, and by extension what triggered it and whether it later reactivated.
Sentinel-1 synthetic aperture radar (SAR) images can be acquired through cloud cover and since 2015, Sentinel-1 has acquired data globally every 6-12 days. These data are sensitive to changes in scattering properties at the Earth’s surface and can therefore be used to constrain the timings of individual landslides. In this seminar, I will use events in Indonesia, Nepal, the Philippines, and Haiti to explore how Sentinel-1 data can be used to (i) assign landslides to particular earthquakes or storms in a sequence (ii) detect multi-stage failure during earthquake sequences and (iii) untangle the combined effect of earthquakes, storms and monsoon rain. With this information, we are able to better understand how landslide hazard and mass wasting evolve in space and time during such sequences.