Jackson’s research has been on the physical properties of earth materials and their application in understanding the Earth’s interior structure and behaviour. He has developed innovative laboratory studies of seismic properties, with special application to olivine-rich rocks of the Earth’s upper mantle. These studies have explored factors such as frequency, temperature, grain size and partial melting that are responsible for seismologically-observed variations in earthquake wave propagation. In parallel, he has contributed to the refinement of theoretical models for thermoelastic and mechanical behaviour in order to provide a robust basis for using the experimental data in elucidating structure and processes in the Earth’s deep interior.