Friday, January 20, 2012

Earthquakes - A competitive sport?

New Zealanders are well know for their competitive nature when it comes to sport, which is great as we are pretty good at it! But it has come of a bit of a surprise lately at the 'mine was bigger than yours' mentality people seem to be getting regarding earthquakes.

I'm sure most people remember the small earthquake in Auckland last year, yes everyone had a bit of a laugh and there were plenty of 'oh no my latte has fallen over' jokes! But in all seriousness Auckland does not get a large amount of felt earthquakes, and living on top of over 50 volcanoes we should let them worry a bit when they do feel shaking - as this is often a precursor to eruptive activity!
Fence crossing the Hope Fault - it was straight until 1888!
Back to the rest of NZ - at GeoNet we record over 15000 earthquakes every year - luckily most are not felt!  We do however, get a few 'biggies' every now and then, here is a wee jaunt through our earthquake history::

North Canterbury 1888 ~ 7.1
This earthquake had a shaking intensity of MM9, it occurred on September 1st 1888. As you can see in the picture on the right - it created a fair amount of land movement, there were also numerous landslides, liquefaction and broken chimneys.

Wairarapa 1855 ~ 8.2
With a maximum intensity of MM10 this earthquake was felt all over NZ,  around 7-9 people were killed and 5 injured. This is also the famous event that uplifted many areas in Wellington including: the Basin Reserve (sports ground) which used to be under water, as well as the harbor ( Lampton quay used to be the waterline), and even the land our airport is on.
Fault Scarp in Buller Gorge.

Buller/Murchison 1929 ~ 7.8
On June 17 this large event occurred, luckily in an area sparsely populated, though it still killed 15 people and injured 1. The quake had an max intensity of MM10 and was felt all over NZ, and damaged many roads, bridges and buildings. The quake also created 38 new lakes after slips blocked rivers (21 still exist today). If you look at the picture on the left, the wee man on the bike is on the other side of the road, now 4m higher than the rest!

Severely damaged road - Hawkes Bay

Hawke's Bay 1931 ~ 7.8
This earthquake caused the largest loss of life and most damage of any quake in NZ history (prior to the Canterbury events) The MM10 event killed 256 people and injured thousands, the earthquake was followed by devastating fires that were unable to be stopped as the water mains were broken. This event also changed the coastline and deformed much land in the area.

Rift in a paddock - Edgecumbe.

Edgecumbe 1987 ~ 6.5
This event is  well remembered in NZ history, it occurred on March 2nd and had a max shaking intensity of MM9. 25 people were injured, and although many buildings collapsed - fortunately they had been evacuated following a large foreshock.

Dusky Sound 2009 ~ 7.8
This event is the largest in New Zealand since Marlborough 1848 and Buller 1929. With a max. of MM7 it triggered numerous landslides and even a small tsunami.

And of course we have the 2011 Christchurch ~6.3 earthquake, with MM9, 181 people killed and 164 seriously injured. For more info on the canterbury events, see our pages here

Although the size of these earthquakes vary, it is interesting to see how the maximum shaking intensity(MMI) is pretty similar. Looking at the maximum shaking intensity is a much better indicator of how earthquakes effect people and the environment, rather than just the magnitude. You can read more on the MMI scale here

Now this is just a few of the major historic earthquakes in NZ, for  more info on these events and others go to our 'historic quakes' page here

And back to my original point(s)
*All of New Zealand gets earthquakes, both small and damaging. So stick together - offer help and words of support, rather than tell people to 'get over it' as it was 'only a baby one'. We are only a small country, stick together!
* and remember to look at the MM shaking intensity of an earthquake before you judge on its size, it may have been small but strongly/widely felt!


  1. Good point. People in general don't seem to be aware of the MM scale, but it really makes a difference to what you feel!

  2. No its not a competition but i guess people feel that mankind has an "off with the old and on with the new" attitude and when an earth-shattering experience (for those involved) is superseded by another incident, whether larger or smaller, somewhere else the people still suffering from the previous one are afraid under it all, that they will be forgotten and neglected.

  3. And as if to prove a point - where is the 7.1, Inangahua quake, (May 24 1968) in your list of significant quakes?? I was living on the West Coast then, and even though the population wasn't the same as Christchurch or Napier there were people hurt and killed and our lives were never the same.
    Although i can say it gave me previous insight when it came to coping with the recent Canterbury quakes.

  4. @MotherGosling - the Inangahua quake is here As i said above, i did not comment on all of the quakes!