Cathedral Square Market 2006 from the belltower. K Pedley / UC
Christchurch's central business district, which contains Cathedral Square, sits on top of sediments deposited on low lying Holocene age coastal margins (i.e. from when sea levels had risen after the last glacial maximum). These include river sand and silt deposits (of the Yaldhurst Member of the Springston Formation) and abandoned overbank flood channels of the Waimakariri River. The deep alluvial (river) deposits, along with the existence of groundwater aquifers, influence ground shaking and affect the foundations of buildings during earthquakes. Christchurch Cathedral had been damaged by earthquakes on several occasions (in 1881, 1888, 1901, 1922) prior to the severe impacts it suffered in 2010 and 2011.