Leighton Watson is a Rutherford Foundation Postdoctoral Scholar at the University of Canterbury | Te Whare Wānanga o Waitaha.
My research focuses on how geophysical data (seismic and acoustic) can be combined with physics-based computational simulations to better monitor and understand natural hazards, with a particular emphasis on infrasound (low-frequency acoustic waves that are below the frequency limit of human hearing) and volcanic eruptions. Motivated by interesting observations of natural activity, a desire to reduce risk, and a strong scientific curiosity, I develop numerical models that are derived from fundamental physics. I validate these models by acquiring my own data, or by comparing with existing geophysical data and visual observations, and then use the validated models to learn about the behaviour of complex volcanic systems in order to improve monitoring efforts and hazard assessment.
My current areas of research include detecting and characterizing snow avalanches with infrasound, simulating geophysical signals from pyroclastic density currents, and infrasonic precursors to lava fountaining at open vent volcanoes. Over the past year, I have also been working on modelling the spread of COVID-19 in New Zealand | Aotearoa.
email: leighton.watson@canterbury.ac.nz
Current Research
PDC_EG_F7.mp4Pyroclastic Density Currents (PDCs) are extremely hazardous flows of hot gas, ash, and rock. They are formed by the collapse of an eruption column or lava dome. PDCs are fast moving, can travel large distances, and are extremely devastating.
In this work, we simulate the flow dynamics of PDCs and calculate the acoustic and seismic signals generated by the flows. This will help monitoring efforts by improving our understanding of how PDC flow properties relate to the geophysical (acoustic and seismic) observed in the field.
COMPUTATIONAL AEROACOUSTICS
We perform simulations of volcanic eruptions using a computational aeroacoustics code. This enables us to solve for the flow dynamics as well as the associated infrasound signal, which is not commonly done. In this project, we explore how infrasound observations are influenced by complex flow dynamics and nonlinear effects in the near-vent region.
CharlesX.mp4ANIMATION1-desktop_with_audio.movInfrasound signals (low frequency acoustic waves in the atmosphere) are frequently excited by volcanic activity at open vent volcanoes. The character of the infrasound signal is modulated by the crater geometry. We investigate how the infrasound signal can be inverted for the crater geometry and lava lake depth. In particular, we examine changes in the observed infrasound signal can constrain (a) lava lake dynamics at Villarrica (Chile) and (b) crater collapse and draining of magma from the summit at Mount Etna (Italy).