Seismically induced boulder displacement in the Port Hills, New Zealand during the 2010 Darfield (Canterbury) earthquake
N Khajavi, M Quigley, ST McColl, A Rezanejad
NEW ZEALAND JOURNAL OF GEOLOGY AND GEOPHYSICS | TAYLOR & FRANCIS LTD | Published : 2012
An analysis of boulders displaced during the September 2010 M w 7.1 Darfield (Canterbury) earthquake provides noninstrumental constraints on the variability, distribution and origin of strong ground motion during major earthquakes. Boulders ranging in mass from 10 to 5000 kg were displaced 8-970 cm laterally from hosting soil sockets of < 1 cm to 50 cm depth at several sites in the Port Hills, roughly 35 km southeast of the earthquake epicentre. Boulder displacement was observed on N-striking (000-015°) ridges above c. 400 m elevation but not on NE-, NW- and SE-striking ridges. The prevailing boulder horizontal displacement azimuth of 250 ± 20° is subparallel with the direction of instrument..View full abstract
We thank GeoNet for making ground motion data available on their website, Kevin Furlong, Timothy Stahl and Brendon Bradley for scientific discussions and Katie Hodgson for her contribution to fieldwork. We would like to thank Robert Hurst for permission to inspect CRLZ site, providing information and scientific discussion. We also thank Mauri McSaveney and an anonymous reviewer for constructive comments. This work was funded by Canterbury University.