The Trembling Earth

now at blogs.agu.org/tremblingearth

February: What a month to miss!

I have finally returned and settled back into life in a quiet NorCal college town after living for a month in the bustle of Beijing, where I conducted four weeks of lab work for my dissertation project.

State Key Lab

I spent my time there working with and in the lab of colleagues at the China Earthquake Administration, a collaboration that I’ll describe in more detail in a later post. Stuck on the other side of the Great Firewall from Facebook, Twitter, and even WordPress, I missed a great deal of the global online fun during some major Earth-shaking events that happened during February. It killed me deep inside, though I had my own great time in Beijing.

I may break these events down into individual posts if I manage the time, but for now I’ll leave you with a cursory summary:

The month began with a monstrous earthquake in the South Pacific, the culmination of weeks of foreshocks in an area that has seen a years-long sequence of large and fascinating ruptures. The M8.0 quake produced a local tsunami that wiped out some villages, and was followed (and continues to be) by hundreds of sizable aftershocks. One of the most interesting aspects of earthquakes is the complex way in which fault ruptures unfold–in both space and time–and the Solomon-Vanuatu Trench has undergone a marvelous sequence.

The next big news was an “earthquake” in North Korea. The Earth did indeed quake, with the strength of a 5.1, but the seismic waves were generated by a huge atomic explosion, not the volume-preserving double-couple of tectonic slip. The CTBTO detected this detonation immediately on instruments worldwide, and, decidedly unconcerned with hiding this from anybody, North Korea quickly proclaimed their third successful nuclear bomb test.

The next rare and global seismic event was not Earth-derived at all: a surprisingly large and exceedingly rare meteor strike rocked the countryside of central Russia, and BOY was it ever captured on film. Thank goodness (or insanity, actually) for Russian dash-cams.

Who knew a meteor sounded like that?? They’ll have to remake Deep Impact. The shockwave from this extremely supersonic space rock was large enough to buffet pressure gauges on the other side of the planet, and the shockwave’s interaction with the ground excited seismic waves that also spread through the planet.

While I was in China, the south of the country had a strange spate of moderate earthquakes, at least one of which proved a successful test of their new Early Warning System. In rural parts of that country many buildings cannot withstand the shaking of even a magnitude 5 earthquake, so these were a bigger deal than they might otherwise have been given the size.

Other seismological things are happening–Christchurch is debating retrofits, for example–so I’ll just have to keep you posted. Glad to be back; you can finally expect more posts in the future!

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2 responses to “February: What a month to miss!

  1. sc100 March 7, 2013 at 1:21 am

    Good to see you’re back! I always look forward to reading your posts.

  2. PuterMan March 7, 2013 at 1:24 am

    Thanks for linking to my seismogram sequence. You might be interested in, or like to be aware of anyway, the fact that I keep the seismograms daily for G.SANVU HHZ, HNZ, HNN and HNE. I like the accelerometer channels as they show large earthquakes better than the normal ones which get so jumbled on large quakes.

    I have a hard drive littered with seismogram image which I am slowly going to transfer to my archive blog.

    I shall take a browse around your blog shortly – looks like my kind of subjects!

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