In World First, CCTV Captures Supershear Velocity Earthquake 27
For the first time ever, a CCTV camera in Myanmar captured real-time footage of a supershear strike-slip earthquake moving at 3.7 miles per second. According to seismologists at Japan's Kyoto University, the analysis has "led to new findings based on real-time visual evidence of tectonic motion," reports Popular Science. From the report: The magnitude 7.7 event took place on March 28 along the Sagaing Fault with an epicenter near Myanmar's second-largest city, Mandalay. Although the initial rupture process lasted barely 80 seconds, it and numerous aftershocks were ultimately responsible for 5,456 confirmed deaths and over 11,000 injuries. Later evaluations indicated the quake was the second deadliest in modern history, as well as the most powerful to hit Myanmar in over a century. According to a separate group's paper published in the same journal, the southern portion of the rupture occurred at an astonishing 3.7 miles per second -- fast enough to qualify as "supershear velocity."
Amid the catastrophe, an outdoor CCTV camera about 74.5 miles south of the epicenter recorded a visceral illustration of its power. Over just a few moments, what at first looks like a single chunk of the ground appears to suddenly divide and horizontally shift past one another in opposite directions. Completely by accident, the camera recorded a direct look of a strike-slip fault, something previously analyzed by remote seismic instruments. To researchers at Kyoto University, the clip wasn't just a jaw-dropping scene -- it was an opportunity to study a strike-slip fault using visual data. You can watch the footage on YouTube.
Amid the catastrophe, an outdoor CCTV camera about 74.5 miles south of the epicenter recorded a visceral illustration of its power. Over just a few moments, what at first looks like a single chunk of the ground appears to suddenly divide and horizontally shift past one another in opposite directions. Completely by accident, the camera recorded a direct look of a strike-slip fault, something previously analyzed by remote seismic instruments. To researchers at Kyoto University, the clip wasn't just a jaw-dropping scene -- it was an opportunity to study a strike-slip fault using visual data. You can watch the footage on YouTube.
m/s does not mean miles per second! (Score:4)
It was around 3m/s.
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I think the 3.7 miles per second is the speed at which the earthquake travelled along the ground from the epicentre. At 50 frames per second, it's travelling 120m per CCTV frame which means there's no recording of the rupture propogating, only of the 1.8 seconds that it took for the ground to move around 3 metres.
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Good thing too because nothing much would survive the ground suddenly accelerating to those kinds of speeds.
I wonder what effect this will have on the rotation of the Earth. Maybe very small, but we are apparently due for another leap second soon. I had better add simulation of that to my code before it happens for real and breaks something.
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You do realise they are about to remove a second from the year because Earth's rotation rate has increased.
I don't think there is a definitive explanation other than a general assumption it's a global warming thing.
My perception is it'll be due to the ice melt at the poles (Greenland and Antarctica). This reduces the weight on the land so the polar land rebounds to equalise. And because that land has raised up then somewhere else has to drop. One of those elsewheres, importantly, is the equatorial girth.
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> I don't think there is a definitive explanation other than a general assumption it's a global warming thing.
That must be the stupidest thing I've read on the Internet today. Leap seconds are not that rare.
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Negative leap seconds are rare, it has never happened before. From Wiki:
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The paper makes no reference of any speed close to 3 miles/second. This would seem like a unit conversion error by Popular Science. .
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The seismic wave can easy travel that fast.
What does not travel that fast would be an optical impression of that wave.
Then again, to get a 2000 miles long split through a continental crust or something similar: you only need two "plates" move away from each other far enough to make the split. That the rift starts at one end and takes 6 seconds to "reach" the other end, and that has nothing to do with speed. The rift is not going that way. The way of making it, is orthogonal to the direction of the rift.
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It is km/s for the RAPTURE (Score:4, Informative)
If you look at the paper, the earthquake moves in m/s, but the rapture itself moves at 3-7 km/s, that's what they call "supershear". Even in the video he shows the graph of the quake at "m/s" but then says "this is opposed to the speed the rapture propagates, at several km per second, faster than an airplane".
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"this is opposed to the speed the rapture propagates, at several km per second, faster than an airplane".
That' explains why it's taking so long for the rapture to get here. I'm waiting to be risen.
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You are confusing the wave velocity with the particle velocity (motion of ground as wave passes through). The P and S waves of an earthquake propagate outwards at many kilometres per second, and fault lines can rupture even faster still. The ground in the video started moving, some other ground many kilometres away started moving one second later. Despite this, individual pieces of ground only travel at metres per second (not km/s).
You literally have maxwell wave equations on your signature!
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The summary says:
There is no "realtime footage of a supershear moving at 3.7 miles per second." The horizon in the video is at most a few hundred metres away. The entire "realtime footage" is of the ground moving at about 3m/s.
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The video shows a small local view of part of this large-scale rupture sequence but does not, in an of itself, show the speed in any readily identifiable form. However, given that all ground visible in the video essentially moves simultaneously, it does provide a lower bound on the order of hundreds
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The velocity of the ground displacement is several metres per second(this is the value you keep mentioning).
The velocity of the wave that causes the ground displacement is around 6000 metres per second (or 3.7 miles per second in noddy units).
At last, something genuinely interesting (Score:4, Interesting)
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Video old. Paper new. (Score:2)
The video was posted May 11 (https://youtu.be/77ubC4bcgRM), and made its rounds through the news then.
The paper is fresh, and the news sites are using the chance to repost the video for more clicks.
Embedded videos suck (Score:1)
Trying to get an embedded video to play inside a web page is a nightmare. Enabling this script or this css, constantly refeshing to see if it will work, is just another example of the enshittification of the web. At this point it's far easier to copy out the link and run it by itself than it is trying to navigate the mountains of cruft web pages have in them.
Re: Embedded videos suck (Score:1)
Is neoliberalism a conspiracy theory that thinks we all agree with it?
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You can still install normal ublock, right off the chrome extension site.
I was in north Thailand when it happened (Score:4, Interesting)
Interesting is: around my area, Lampang province, the quake was very strange. ... and realized he is feeling the same.
It lasted long, perhaps 5 minutes. But you only felt it in your body.
Actually when it started I assumed I have a stroke, and tried to sit down before I fell down.
Then I saw my step son holding the wall
We ran outside, and shouted to the other houses to get out, but people did not realize what is going on.
We have high water towers here. Very simple constructions. Four poles about 30m high. A big tank on top. One would assume those were shaking or even collapsing. But nothing happened. They did not even move visually.
That was about +500km away from the epicentre. Then watching news, we saw sky scrapers in Bangkok shaking, spilling water from the roof top swimming pools. That is another roughly 1000km away.
I experienced a few quakes before, that were much much weaker on the Richter scale but had much more visual and physical impression on me. Like waking up at home in my bed, and the lamp on the ceiling swinging back and forth one yard.
A few minutes later one of my best friends was calling at night ... he used to live in Japan and in Italy, close to Milano. He was "used" to earth quakes and wanted to confirm on me.
Well, this Myanmar quake had many small after quakes, most of them I did not notice. Only saw the news about it. And then, 6 weeks later: a very very long after quake again. Very unspectacular. But you could not walk from one side of the room to the other. It is something in the bones, nerves, what ever. Your body does not want to go. It "thinks" it is out of balance all the time and tries to adjust for nothing. The dishes in the cabinet at the wall did not even make a sound. It was just an odd wave going through your body and messing up your ears or knee nerves preventing you from feeling standing stable (while you actually were standing stable).
Well that video was useless cos.. (Score:2)