On Friday 23rd December, shoppers fled stores and supermarkets as roof tiles fell in, supplies flew off shelves, and panic spread through shaking shopping malls. Many people were injured and taken to hospital, but no fatalities were reported.
In the eastern suburbs, many distraught residents grappled with the heart-breaking scenes of more liquefaction flooding their streets, often mixed with sewage from leaking, broken sewer pipes.
In the steep, coastal suburb of Sumner, rockfalls were a hazard again with massive rocks and slips crashing down the cliffs and raising clouds of dust.
Disruptions to Electricity and Airport
Electricity supplies were disrupted to wide areas of the city, and the lines companies were busy trying to restore power. On Saturday most homes again had power with just 50 households still waiting.
The airport was closed for a few hours on Friday afternoon, as authorities checked the runways and buildings for damage. Flights into and out of Christchurch were disrupted, but restored later that evening.
Christchurch has been free of major earthquakes since the last big shake in June this year that followed major shakes in February 2011 and September 2010. Residents were able to relax and continue to rebuild their lives, dealing with the frustrations of insurance claims on damaged property and houses.
The recovery was thrown into chaos on Friday, as the new earthquakes will mean a new round of building, house and property checks for damage for new claims and before existing claims can be progressed.
Diary Of An Earthquake Swarm
In recent months, seismic activity had fallen relatively quiet in the Canterbury region with only small, mainly magnitude 2-3 shakes recorded. Most of these go undetected by residents, but are recorded and shown on the Geonet website.
The earthquake swarm is made up of activity at a depth of four to 15 kilometres, located 10 - 20 kilometres east of Christchurch city in Pegasus Bay.
On Friday morning, a few of these small and shallow M2-3 earthquakes were recorded near Christchurch at 7.49am (M2.6), 10.15am (M3.0) and 11.47am (M2.8). Then at 1.58pm the city was hit by a long, rumbling tremblor that registered M5.8. (This was reportedly felt as far north as Lower Hutt near Wellington, and as far south as Oamaru and Queenstown).
Aftershocks from this initial shake continued at short intervals with a sharp M5.3 at 2.06pm, another seven shakes mostly around M4 in the next hour, and then a whacking M6.0 aftershock at 3.18pm. This was experienced as another noisy, sustained and violent shake.
Cleanup Allows Shopping to Continue
Over the following few hours, aftershocks continued every five to 10 minutes, and mostly around M4 with another big shake of M5.1 at 4.50pm. These continued all evening, mostly between M3.2 and M4.6 and residents were jolted again by a 5.1 at 6.37am on Saturday 24th December. Saturday followed a similar pattern to other major earthquakes in the city with seismic activity rumbling on at a rate of 2-3 shakes an hour, usually around M3-4.
Progress on cleaning up the damage from this latest round of earthquakes will depend on seismic activity decreasing and no further large shakes. City Council workers were scrambling to have the worst damage fixed before Christmas Day.
Most shops were able to re-open for Christmas shopping on Saturday in the major malls around the City, but many were harder hit, and faced with the prospect of staying closed and missing both Christmas Eve and Boxing Day shoppers.
Sources:
Earthquake info: www.geonet.org.nz
Also animated Christchurch Earthquake Map at this link.
Canterbury Television CTV at this link.
