Christchurch Earthquakes

4 Sep 2010
26 Dec 2010
22 Feb 2011
13 June 2011

Favourite Places

The week 11-19 Feb 2011 during the Festival of Flowers I was playing piano in the Cathedral 1-2 hours most days

Cathedral 1Cathedral2

Afternoon of Tue 22 Feb 2011:

My Software Firm (Beyond) used to be in this building - 2nd floor, the middle window and the two the right of it

I used to live in this flat when I was at university..

Friends house 200 metres down the road
Soleares Ave

Favourite Cafe - before and after
Note almost all buildings in the second photos have issues - including the 2 large buildings.  Westpac future unkown, Centra Hotel (right white building) across the road from the Grand Chancellor now has a similar lean since 13 June

One of the demolitions that no-one will mourn:

Festival of Flowers was organised from the upstairs offices without walls - they were there

My Kitchen 22 Feb



A favourite shop
Piko Wholefoods

Civil Defence Film of Chch CBD Red Zone

Quake captured on Liverpool St CCTV
(note Liverpool St is the street on the left of the Kenton Chambers building pictured above)

Figures on Peak Ground Acceleration

The Peak Ground Acceleration (PGA) recorded at Christchurch Botanical Gardens - Comparisons:

4:35am, September 4 2010 Magnitude 7.1: Between 0.15 and 0.20 times the power of gravity

10:30am, December 26 2010 Magnitude 4.9 : 0.48

12:51pm, February 22 2011 Magnitude 6.3: 1.80

Statistically in terms of PGA, the February 22nd quake was a 1 in 1000 year event. Part of the reason for the destruction in Christchurch is that New Zealand buildings with a ~50year life span are only required to withstand a 1 in 500 year event, which is probably adequate enough. Usually. Christchurch was just unlucky that such a fast and shallow (not to be confused with strong) earthquake struck so close to the city.

In fact this was the fastest earthquake to hit a significant population base ever. The below table (while not the recording at the Botanical Gardens site) shows the comparison between significant earthquakes around the world. The 2.20g figure was recorded in the Christchurch suburb of Heathcote, near the epicentre of the quake.

PGA   Mag   Depth   Fatalities         Earthquake
2.2g   6.3     5km      166*                2011 Christchurch earthquake
1.7g   6.7    19km     57                   1994 California earthquake
1.26g 7.1    10km      0                    2010 Canterbury earthquake (reading taken in Darfield, close to epicentre)
0.8g   6.8    16km     6,434               1995 Kobe earthquake
0.51g 6.4                612                  2005 Zarand earthquake
0.5g   7.0    13km     92,000             2010 Haiti earthquake

Other observations