Shaken

Earthquakes are pretty rare in Auckland. This afternoon, we had two within 5 minutes. It was pretty scary.

The first earthquake struck at 4:01pm. It was a light one, only magnitude 3.1, with a depth of 4km and centred about 15km from Auckland. I was sitting at my desk at the time, and felt a couple sharp jolts and rattling in the house, and my computer monitor swayed. It felt much stronger than any earthquake I’ve felt, certainly stronger than the first one I felt in Auckland, just over six years ago.

Roughly five minutes later, we had a second earthquake: It was a moderate quake, magnitude 3.9, about 6km deep and in roughly the same location, 15km from Auckland. This one was a much bigger deal: The house shook and rattled quite a lot and it went on for easily four times the length of the first one, though still only a few seconds (earthquakes seem to last longer than they really do). This one scared me, primarily because it lasted longer, and also because it was stronger. Nigel didn’t notice because he was standing in the kitchen at the time.

What also made the earthquakes scary is that they both happened under Mototapu Island, which is right next to Rangitoto Island—a dormant volcano that was the most recent to erupt, some 700 years ago. Experts say that earthquakes will precede a new volcano for days or weeks. They don’t know where or when one will emerge, just that it’s almost a certainty one will—eventually.

The video at top of the post is of Richard Woods, the Hazard Advisor for the Civil Defence and Emergency Management department of Auckland Council. He explains the earthquake risk for Auckland. In the video below, he talks about the volcano risk for Auckland.

It’s worth noting that the biggest threats to Auckland are still what they are for most of New Zealand: Flooding from storms. Coastal regions are also at risk from tsunamis, something that experts say are a bigger threat than they used to think.

Nowhere is without risk from natural disaster. Life on this planet is far more tenuous than any of us want to realise. So, with the possibility that some disaster could kill us or destroy everything we own, we all ought to live our lives as if it’s our last day—carpe diem, and all that. Most of us don’t do that, of course: We choose to believe that disaster won’t happen.

Disaster didn’t hit Auckland today. It probably won’t the next time the earth shakes here, either. One day, however, it may. And that’s enough to leave anyone a little shaken.



Update: GeoNet's press release has more information about the quakes, including links to information about the 2005 and 2007 quakes.