“Some models are right enough”: Geophysical models for hazards, risks and resilience
2024 Bristol GA Autumn lecture #4
“All models are wrong.. but some are right enough”, says Prof. Jeremy Phillips (Earth Sciences, University of Bristol), paraphrasing the statistician George Box, who many associate with the aphorism “All models are wrong, but some are useful”.
Models are useful for many applications in geography and environmental sciences, and Jerry presented some excellent examples from his field of expertise, that is geophysical flows and hazards.
There were a hundred students and teachers in attendance on the evening of 3rd December 2024. The first half of this excellent lecture focussed on physical geography or geology, specifically, natural hazards and the underlying physics and maths. The audience were walked through the physical processes involved in range of settings from across the globe: effervescent eruption of volcanic gases from a lake (Lake Nyos, Cameroon); the physics and transport of ash in plumes from a volcanic eruption (Eyjafjallajokull, Iceland); and flash floods or mudslides in the Andes (the huaycos of Peru).
We did see plenty of mathematical equations, but these were described in ways that could be understood, with simple graphical illustrations and animations. Jerry introduced us to entrainment, buoyancy, eddy behaviour and more in an engaging manner. If you are interested to look into this further, see worksheets in resources
The second half of the lecture focussed more on risks, resilience and mitigation . We were introduced to a project based in Peru, where mathematicians and geophysics teams worked with local communities and experts to consider early-warning systems for flash floods (see additional information). In some urban settings, households are in the direct path of flash-floods. These can occur in response to low intensity rainfall events because of the barren surface cover and steepness of the confined catchments. The power of community knowledge was brought to the fore to produce useful models.
This was just the right sort of mix between of physical and human geography to appeal to all in the lecture theatre. There were plenty of relevant case studies that can be used to add depth to any questions on such matters in future exams.
The slides for the earlier section of the talk are provided in resources. The material associated with the community-based work cannot be released until work is published soon.