Re: Giant Earthquake just hit Japan
Posted: Sun Mar 27, 2011 1:55 pm
Keep the videos coming, Hairy.
Why? wrote:Sometimes I question why they don't build these things underground.
wouldnt all of the nuclear biproduct simply amount undergruond and not go into the ozone so therefore amass and kill every single person? not to mention you'd desecrate the soil if it would go topsideWhy? wrote:Sometimes I question why they don't build these things underground.
Can you please grammar this better?incandescent wrote:wouldnt all of the nuclear biproduct simply amount undergruond and not go into the ozone so therefore amass and kill every single person? not to mention you'd desecrate the soil if it would go topsideWhy? wrote:Sometimes I question why they don't build these things underground.
Why? wrote:Can you please grammar this better?incandescent wrote:wouldnt all of the nuclear biproduct simply amount undergruond and not go into the ozone so therefore amass and kill every single person? not to mention you'd desecrate the soil if it would go topsideWhy? wrote:Sometimes I question why they don't build these things underground.
Also @Hairy, love that first pic man. I don't care if it's fake or not.
http://www.newscientist.com/article/mg2 ... ology.htmlTypically a subduction earthquake - in which one tectonic plate pushes beneath another - rips in one or two directions along a fault: on a north-south fault line, say, a rupture heads north, south, or north and south at the same time. But Kiser and his colleagues found that the Tohoku quake ripped left, right and centre along the fault like the starbursts of a fireworks display (see diagram).
"When we imaged the main shock, the propagation of energy was all over the place," says Kiser. "We believe this is the most complex rupture behaviour ever observed." The team reckons the pattern may partially explain why the quake was so ferocious.
Their latest estimates of how far the tectonic plates slid past one another suggest that at its maximum the slip was 60 metres - a figure so big that every researcher New Scientist contacted asked in astonishment for the figure to be repeated. Such a massive shift is unprecedented in the recorded history of earthquakes.
total energy released by mag 6+ quakes in past 108 yearsRupture propagation - Direct imaging of the rupture from back-propagation of seismic waves
We imaged the source of the March 11 2011 M9.0 earthquake in Japan by back-projection of the seismic waveforms recorded by large arrays at teleseismic distance. This source imaging technique allows to track the location and migration of the multiple sources of high-frequency radiation that compose an earthquake rupture front. Our particular approach is based on high-resolution array-processing techniques, such as MUSIC (Mutiple Signal Classification -- Schmidt et al,1982; Goldstein and Archuleta,1991) and CINT (Coherent INTerferometry -- Fletcher et al, 2006; Borcea et al, 2005).These techniques achieve higher resolution than conventional beamforming and are more robust against aliasing.
Data selection and processing
We applied the MUSIC and CINT back-projection techniques to seismic data recorded by the USArray at epicentral distances between 70 and 90 degrees, filtered between 0.5 and 1 HZ within 10 seconds long sliding windows. The large aperture of the USArray in the radial direction provides good spatial resolution along-strike despite its unfavorable source-array direction sub-parallel to the trench axis. Test were also performed using a network of seismological station in Europe (Figure 3) or New-Zealand. The warm colors in the movies (Figures 1 and 2) correspond to high amplitudes of the MUSIC pseudo-spectrum and of the network-averaged cross-correlation coefficient, respectively. They indicate the location of the major areas of high-frequency radiation on the fault. The white star is the mainshock epicenter and the white dots are the epicenters of M>6 foreshocks and aftershocks from NEIC. The white line is a reference along-strike direction on which we project these images to produce the spatio-temporal view of the rupture shown in Figures 4 and 5.
Results
In the initial 100 seconds the rupture propagates slowly to the North and down-dip. Around 100 seconds into the event, two rupture fronts split up. The southward propagating rupture becomes dominant and sustained until 170 seconds.The averaged rupture speed to the south is 2.8 km/s. These features can also be discerned, although with lower resolution, in our back-projection images based on data from Europe (figure 3) and New Zealand.
MUSIC back projection (USArray)
Coherent interferometry (USArray)
MUSIC back projection (dense European network)
http://www.tectonics.caltech.edu/slip_h ... rojection/