Seminar by Varya Bazilova (Utrecht University, NL) :
Spatial distribution and controlling factors of the debris flow hazard across High Mountain Asia
Abstract: Debris flows and floods and flash floods pose hazards to the densely populated areas of High Mountain Asia (HMA). The continuous decline in the cryosphere across the region such as glacier mass loss and permafrost thaw leads to exposure of the unconsolidated debris material and sediment deposits. Even though, some statistical assessments show, that morphometrical characteristics of the catchments can control the debris flow susceptability/probability, the climatic influence on it remains unknown.
We identify the controlling parameters and quantify the likelihood of debris flow and floods and the change in likelihood due to projected regional climate and cryosphere changes. Based on visual inspection of alluvial deposition and surface properties of the alluvial fans, we identified catchments across HMA where floods or debris flows occur. We built a dataset with morphometrical (e.g. catchment area, perimeter, slope, elevation range, Melton ratio) and climatic features (e.g. temperature and precipitation regime, freeze – thaw cycles, glacier and permafrost area) and build a CatBoost gradient boosting based machine learning classifier.
We identify that debris flows are more likely to occur in small catchments, defined as catchments with small Melton ratio and high slope. The erosion mechanisms and the total amount of snowfall in the catchment also add a lot of information to the model. However, the catchment characteristics, controlling the debris flow activity differ between mountain ranges, depending on its location. Projected regional climate change will decrease the probability of the debris flows. It will also increase the probability of the flood being a dominant process in the catchment across the entire HMA.
The talk is in Aud 1 in the Geology Building. It is also possible to follow at Zoom.
Video link to the lecture will be sent to the mailing lists alle@geo and geohyd-info@geo. If you want to subscribe to the geohyd-info@geo list send an email to Anita.
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About the seminar
This seminar is offered by the Section for Geography and Hydrology , Dept. of Geosciences, University of Oslo. The GEOHYD seminars are announced as lunch seminars so bring your lunch if you want to
The seminars are open to everyone interested, and especially students are welcome.
The Lunch Seminar Team
– Yeliz and Thomas