June 14, 2011

A fresh temblor in the Canterbury sequence

Posted by Austin Elliott

Christchurch, New Zealand has been plagued by earthquakes for the past year, ever since a M7.1 ripped along a previously unrecognized fault in the Canterbury Plains last September. This quake produced a vigorous aftershock sequence, including most notably a large triggered quake (with its own vigorous aftershocks) directly beneath Christchurch. The city has been reeling from that M6.1 quake for four months, beleaguered by aftershocks and duly warned (as of a week ago) that they’re not out of the woods yet. Sure enough, a magnitude 5.5 5.2 startled the city at 1pm on Monday, June 13. Nature seems to have given fair warning, because less than an hour and a half later a magnitude 6.0 rippled through the region. This earthquake, though late and large, was an aftershock of the 22 Feb. earthquake, and has spawned its own ongoing sequence of aftershocks.

It may be decades before another earthquake generates as much eye-witness footage as the 9.0 Tohoku monster in Japan, but there’s a fair bit from some neat vantage points in New Zealand during this latest quake. One interesting aspect many of these videos offer is the comparison of duration and intensity between the shaking from the 5.2 “foreshock” and the 6.0 that followed.

A back yard is rattled by the 5.2 (nice shot of the trees getting yanked around, and a mini-seiche in the pool):

This lucky lad turned his camera on just in time for the foreshock:

A widely publicized clip shows the earlier earthquake interrupting a Maori ceremony:

This home surveillance system captures both quakes in full… with 4x the vantage points!

And finally, this Kiwi man is tiptoeing around the toppled contents of his house following the “biggie” while aftershock upon aftershock inhibit any feeling of settled comfort. His heavy use of reflexive verb formulations takes a lot of the blame for the destruction away from the Earth and lands it on the more direct culprits: poorly secured cabinets and appliances! Nonetheless the ongoing tremors remind him/us who’s in control. This is when you ask yourself when it will stop. If we only knew…

 

[Updated]: A few more videos of the 6.0 are collected in my next post.

 

Hope you’re getting rest and respite, Christchurchians, or at least finding some way to get on with life through the bucking of the Earth!