Are large plate boundary faults well behaved? Variability of rupture recurrence on the Alpine Fault
2008 – 2011
Funder: Marsden Fund, Royal Society of New Zealand
Contact:Kelvin Berryman
Earth’s tectonic plates are constantly in motion and one of the main effects of this movement is the occurrence of large earthquakes (magnitude >7) on major faults at plate boundaries. Unfortunately, these are also the events that wreak havoc on society. For this reason we seek to improve understanding of plate boundary fault behaviour. There are two competing hypotheses: that major faults rupture at evenly spaced intervals (characteristic behaviour) or that they have periods of frequent rupture interspersed by quiescence (clustered behaviour).
New Zealand’s own major, plate boundary fault – the Alpine Fault – is one of the fastest slipping faults in the world and is known to rupture in large earthquakes. However, its long term behaviour is unknown. Recent field investigations revealed a unique opportunity to develop a long earthquake record for the Alpine Fault. Evidence of 20-25 earthquakes occurring over 7000 years is preserved in lake sediments in South Westland.
This project will determine ages for these earthquakes and use them to test the characteristic versus clustered behaviour hypotheses. Records of this quality are rare worldwide so, through this work, New Zealand has the potential to make an important contribution internationally, as well as dramatically improving local earthquake hazard estimates.
Associate Investigators:
| Dr Glenn Biasi | University of Nevada, Reno, USA |
| Dr Ursula Cochran | GNS Science |
| Dr Shmuel Marco | Tel Aviv University, Israel |
| Ms Daniela Pantosti | Istituto Nazionale di Geofisica e Vulcanologia, Italy |
| Dr Christine Prior | GNS Science |