Most of his research focusses on understanding earthquakes and how they affect us. This includes understanding why earthquakes occur where they do, how big they can be, and how efficiently they generate seismic waves. It also involves the study of the generation and propagation of tsunamis, and the focusing and attenuation of seismic waves by earth structure (https://earthsciences.anu.edu.au/people/academics/professor-phil-cummins).
