Earthquake accounting: A new way of including local soils in the predictions of ground shaking

Published 2 November 2017

The damage from the 2010 and 2011 Canterbury Earthquakes was worse than you might predict based on the magnitude of the earthquakes. This was in part due to the local geology leading to differences in soil structure at different locations. In Canterbury, the nature of the local geology resulted in severe ground shaking and extensive liquefaction leading to more extensive damage. Earthquake scientists also failed to accurately predict these effects because the current models are too simplistic for most locations and only look at one dimension of the seismic waves.

Dr Christopher McGann from the University of Canterbury’s Civil and Natural Resources Engineering Department, together with colleagues from New Zealand and the USA have been awarded a Marsden Fund Fast-Start grant. This team will develop more sophisticated methods to improve the accuracy of ground shaking prediction for specific locations. To accomplish this they will use data from over 5000 ground shaking measurements from over 100 Japanese earthquakes, considering local geology and ground motions in three dimensions.

This study is extremely timely. Recent earthquakes around the world have generated considerable interest in better understanding these local effects. It is critical that an improved analytical framework is developed, so that the most accurate predictions of ground shaking can be adopted worldwide. More accurate predictions could then be used to inform the design and construction of safer urban structures, such as high-rise buildings, bridges, and other infrastructure.