Apologies for the tardiness. I suppose for some of you this is Sunday evening reading, if that’s what people even do on Sunday evenings. Maybe for those of you hunkering down in the U.S. midwest.
Here are two weeks’ worth of seismic tidbits I posted on Twitter, since the first week was a little dry. Catch up on all things quakey!
“The Earthquake Machine” How do you scale down faults so that you can understand their frictional and mechanical behavior in controlled tests? Popular Science has a neato infographic on the equipment used in rock mechanics tests–earthquake laboratories. http://www.popsci.com/technology/article/2013-03/earthquake-machine
Animal earthquake predictors There has been a modest buzz this week about research on a longstanding legend of seismic phenomena. Animals have occasionally been reported to appear to foretell earthquakes, but anecdotal evidence generally fails any rigorous scientific test, and most such observations are thus dismissed as unreliable indicators of any impending quake. Researchers in Germany, however, have begun to study ants that live in colonies along fault lines. Surprising finding: their level of activity changes from a daily average before small tremors. I wouldn’t make too much of this yet, but I think it’s really cool to finally see some potential for scientific tests of a long-standing, intractable myth/puzzle about quake phenomena. Now if only we could fill all our fault lines with German Redwood ants…. I wonder if they distinguish between magnitude 2 and magnitude 7…
A modest but substantial 5.8 tremor rattled the southern Japanese island of Honshu this week, doing a fair bit of damage on Awaji island and the densely populated area surrounding it. A collection of videos record the shaking from a few urban cameras, the second of which demonstrates the noise created by a rattling city:
YouTube user KOJI PEI posted a video showing a real-time (actually ~2 or 3x speed) animation of shaking intensity at each of Japan’s seismometers during this quake. I’m not sure where this video came from nor how specifically it was generated (it appears to be maximum acceleration averaged over a several second time window), but I’m hoping to find out and to find more like it. You can see seismic waves radiate outward from the epicenter, with the relatively gentle P-waves leading the charge, and swishy S-waves ringing outward behind them.
The principle of base isolation is already successfully applied in buildings around the world, and this mini-version may be hugely popular with companies and museums whose equipement and specimens need to be seismically protected. One of the commenters also has some insightful things to add, including the major deficiencies in maximum displacement and vertical protection.
Big news on a big move this week – I’ll update you all shortly!
I'm a Ph.D. student in earthquake geology, using topographic and stratigraphic investigation to unravel the seismic history and dynamic behavior of continental faults. I get excited about all things seismological, and I bring them to you here.