Dr Chris Massey, a researcher with GNS Science in New Zealand is currently visiting the Institute of Hazard, Risk and Resilience.  During the 2011 Christchurch earthquake large boulders were unhinged from extremely steep slopes and crashed into houses below (see Christchurch earthquake secondary hazards).  In this highly informative and exciting video, Chris presents some of the work they’re doing in studying how large rocks travel down steep slopes.