Geoscientist Online

Twenty-nine Nottingham geologists on a 'geotour' holiday were caught up in the 6.3 Mw earthquake in Christchurch. Dave Wilson* tells his story.

Geoscientist 20.05 June 2011

It was the last day. Suitcases packed, we were killing time before our flight. It was raining so when the earthquake struck I was on the top floor of the Canterbury Museum, examining an exhibition devoted to a centenary of Antarctic exploration. There was no warning; no build-up in the intensity of tremors, just one enormous bang and a terrific lurch followed immediately by a series of violent jolts that went on for about 15 seconds before subsiding.

GET ME OUT OF HERE

We were flung across the room. Lights went out and alarms sounded. I realised it was an earthquake almost immediately (we'd seen the effects of the September event the previous day), and made for the exit; but the tremors made it difficult to keep our feet and run in a straight line. Tables, glass and crockery crashed to the ground in the restaurant, as people headed for the stairs and emergency exit.

Once outside we moved away from the building. Fortunately the museum backs onto the open space of Christchurch Botanic Gardens, although even here it was not entirely safe as branches fell from trees; in other parts of the gardens whole trees were uprooted.

By this time we were joined by a flood of people from Christchurch central business district (about a quarter of a mile away). Aftershocks came and went every ten minutes or so, some almost as strong as the original. Files of schoolchildren arrived (they all get earthquake drill at school) and walking wounded, many visibly shocked, on their way to the hospital. Eventually about 1500 people gathered, telling how shops, offices and the Cathedral had collapsed, and how people had been trapped.

LIQUEFIED GROUND

The shaking had induced liquefaction of the ground. Small mud 'volcanoes' had developed along fissures; parts of the playing fields had flooded and, interestingly, the River Avon (actually a large stream) had risen by about half a metre and was turbid with mud. Water mains had cracked and there were rifts across tarmac paths and roads.

We assembled at a Red Cross centre, converted from a marquee due to be used for a forthcoming flower show. However, liquefaction turned its floor into a sea of mud and we had to wait several hours while it was cleaned, boarded and covered to allow people to sit down.

To be processed as a refugee by the Red Cross is an interesting experience, but I now understand why it is necessary. Once completed, the Red Cross are able to inform next-of-kin, arrange accommodation and flights out; they also arrange food and medicine. The consulates are involved also for those who have lost passports and belongings, and who need repatriation.

I will not forget the help given by ordinary New Zealanders, who offered us food, accommodation, transport and sympathy even though they were equally shaken. We flew out, two days late, via Los Angeles; our luggage is still in our hotel. We may get it back when the building is safe to enter.

• Read more about the Christchurch Earthquake in an Online Special by Dave Boon (BGS).