People in Australia have often asked me what an earthquake feels like. Most Australians have never felt one before. It feels a little like being on a roller-coaster ride but without a seat belt on. If you’re inside a house the furniture rocks, slides, or tips and you can hear things fall and smash. If it’s night-time you are plunged into darkness. You call out to your children but can’t hear your own voice because the rumbling of the earth and the shaking of the house obscures it. You can never be fully prepared because they strike so suddenly and without warning. Even running to the nearest door frame is a risky undertaking: imagine trying to walk on a roller-coaster mid-ride. If your children are in another room then you feel totally helpless and unable to reach them.
I’ve heard people question why Christchurch is experiencing so many aftershocks compared with places like Haiti and Japan. I am not a geologist but as far as I’m aware those places have also experienced aftershocks commensurate with the size and location of the initial earthquake. There is nothing unexpected about the sequence of aftershocks in Christchurch. Haiti does not have the huge network of seismic instruments that Christchurch has so many of the aftershocks simply go unrecorded. While Japan does have a dense network of seismic instruments the initial earthquake was offshore – some 160km offshore – where there are no instruments.
The Mag. 6.3 earthquake we had on June 13th was about 10km SE of Christchurch. This makes a huge difference to those of us north of the city. Nothing in our house fell over. It’s fair to say I have secured pretty much everything now and have removed all the pictures from the walls of our house. But there are still some unsecured items of furniture like our washing machine. I heard through a friend who lives on the hill just above the epicentre that their washing machine toppled over. I can’t help but wonder what would happen if the next Mag. 6+ is under our house.