Lateral spreading displacements from the 2010 Darfield and 2011 Christchurch earthquakes

Abstract

The 4 September 2010 Darfield and 22 February 2011 Christchurch earthquakes caused significant damage to Christchurch city and surrounding suburbs as a result of widespread liquefaction and lateral spreading. Field investigations were conducted following these two events in order to measure permanent lateral ground displacements in areas significantly affected by lateral spreading. Ground surveying techniques were used to estimate total displacement along specific transects. A total of 145 transects were completed in the areas of Kaiapoi, Brooklands, and various suburbs within Christchurch City. Maximum lateral displacements measured in these areas from both events ranged from approximately 0⋅5–3⋅5 m, causing significant damage to structures and lifelines within the spreading zone. This paper presents a summary of the locations surveyed and results for each event, assessment of the ground surveying methodology, and a comparison of 22 locations which were surveyed following both the September 2010 event and the February 2011 event.