M6.2 Quake this Morning: A One-Off, or Prequel to the Next Big One? (AkihabaraNews.com)

I wrote this for AkihabaraNews earlier today. I know I usually post snippets and link through to the article there but this time I'm posting the whole thing... Because importance.

Click through to the site anyway for the link juice if nothing else.

image source: Tenki.jp

M6.2 Off the Izu Coast 

At 5:18 this morning, we were woken up by a fairly sizeable shake. With a magnitude of 6.2 at the epicentre and clocking in at around Shindo 4 in my area, it's the biggest one I've felt since the aftershocks of 3/11. It was a fairly long one, and until it peaked and flattened out, it felt like it might have grown into the next big one. It didn't, thankfully.

Apart from shaking a saucepan off the drying rack in the kitchen, there was no damage. But the timing was astounding.


The day before (March 4), a Japanese truth blog (the kind that report on the things that mainstream media sometimes ignores) had a post detailing a series of over 20 small tremors that occurred near Hida in Gifu Prefecture. It went on to mention that, 12 days before the Great East Japan Earthquake and Tsunami on 3/11/2011, a similar pattern of small tremors in quick succession was observed in the area.

Also, in the build-up to 3/11, days before and 40km away from the epicentre of the big one, there were a number of foreshocks in the M6 range, with the biggest being an M7.9. Post 3/11, there was a lot of speculation and talk, especially from people who had lived through a few, about "earthquakes cycling through regions of Japan" and "Tokai and Kanto being overdue for another big one."

Giving the speculation a measure of scientific credibility, low-frequency seismic noise mapping also indicates that the area where the quake hit this morning is approximately where the next big one is likely to occur. Add the recent eruptions on Nijima in the Ogasawara island chain (near the epicenter of this morning’s quake), reports of increased crustal deformation and volcanic activity in the area, and it does seem appear that something is afoot.

image source: Saigaijyouhou.com

The Big Question: 

Is this pattern of small tremors in Gifu, followed by foreshocks in a region with 'high entropy' values and increased volcanic activity, a reliable enough indicator that in the next week or two will bring another big one somewhere in the Tokai/Kanto area?

Nobody can say for certain until it happens, but for what it's worth, with the amount of technology being thrown at earthquake research only increasing, patterns like this will continue to be found. We have nothing that can stop the quakes from happening, but if we can at least have a way predicting seismic activity and integrating an alert system for potential quakes, people can be better prepared to deal with the next big one when it happens… Because it WILL happen.

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