Massive blast in Beirut


Our city is trashed, let's make it worse

Why can't people protest without destroying things ? Unfortunately it looks like things are going to turn worse for the Lebanon people, maybe civil war ?
 
Minusorange said:

Our city is trashed, let's make it worse

Why can't people protest without destroying things ? Unfortunately it looks like things are going to turn worse for the Lebanon people, maybe civil war ?
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Looking at some of the images I doubt they can make it worse.
 
RoboCod said:
The overpressure wave is deadly nearby but pressure soon dissipates in an open environment. The blast/shrapnel wave is more deadly. In the Beirut instance I believe the overpressure would be deadly out to 1000ft but when you get to 6000ft away it probably wouldn't.
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StriderX was asking about surviving at <100m from the blast, hence the importance of the overpressure at such a close range but otherwise I agree, the blast wave of buildings, rubble, glass etc becoming shrapnel was the biggest danger once you're outside the fairly small overpressure range.
 
this was posted a few hours ago, HD footage of the blast.


The blast itself happens at 9m37 but after that it's replayed in slow motion. You can see the shockwave destroy the buildings piece by piece as it moves closer to the camera. Terrifying.
 
I just figured that there must be points behind such a large building (with the source of the pressure wave being pretty much exactly on the other side) that one could feasibly survive such that any pressure differences is cancelled out or minimised.
 
StriderX said:
I just figured that there must be points behind such a large building (with the source of the pressure wave being pretty much exactly on the other side) that one could feasibly survive such that any pressure differences is cancelled out or minimised.
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It would seem logical. However I'm not sure how much the positive vs negative pressures come into play.

3rd edit: the notes have a thing at the back about please don't share online. I presume that means uploading the course material but scrubbed out just in case it means the content in general.
 
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james.miller said:
this was posted a few hours ago, HD footage of the blast.

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The audio in that video is wierd. You can clearly hear the fireworks cooking off but the sound is from the left and the wind is also from the left. I wonder if there's a wall just off-camera to reflect the sound?
 
StriderX said:
I just figured that there must be points behind such a large building (with the source of the pressure wave being pretty much exactly on the other side) that one could feasibly survive such that any pressure differences is cancelled out or minimised.
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Pressure waves like that are very complex and especially around openings in buildings, etc. can do things very different to what you expect - even with massive explosions you can get patches where people can survive and sometimes a small explosion can be amplified in a certain place easily killing someone, etc.
 
I was in Syndey once for the fireworks. First the shockwave would shake you front-on. Then the tall buildings behind would knock it back and you'd get the reflection push you from behind. And that was just relatively small thumps, like being in a nightclub when they pump the bass so you can feel it.
 
james.miller said:
this was posted a few hours ago, HD footage of the blast.


The blast itself happens at 9m37 but after that it's replayed in slow motion. You can see the shockwave destroy the buildings piece by piece as it moves closer to the camera. Terrifying.
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So there's a fire, then there's a small explosion with fireworks or munitions cooking off which then leads to the deadly mega explosion ? It'll be interesting to know what exactly happened and what was actually on fire initially
 
james.miller said:
You can see the shockwave destroy the buildings piece by piece as it moves closer to the camera. Terrifying.
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Those warehouses near the blast you can literally see them almost atomised and then basically blasted against the buildings further away like sandblasting.
 
Rroff said:
Those warehouses near the blast you can literally see them almost atomised and then basically blasted against the buildings further away like sandblasting.
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EvEXVOg.jpg


Presume anybody caught in the fireball would be toast rather than pulverised by the shockwave
 
Minusorange said:
So there's a fire, then there's a small explosion with fireworks or munitions cooking off which then leads to the deadly mega explosion ? It'll be interesting to know what exactly happened and what was actually on fire initially
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Not sure we will ever get a proper account of what happened.

Looks like the early bit of that video is mostly stuff like wood and paper, etc. burnings, then hits something ammo, firework components maybe even aerosol canisters which cook off spreading it further with maybe some fuel oil or something (not sure if that is what causes the change in colour or attempts to fight it) which then causes a bigger cook off of whatever which triggers a catastrophic chain reaction.

EDIT: For all the power of it though - I still don't believe it to be 1/5th the size of the atom bombs used on Japan - if that was true many more of those buildings in the foreground (camera POV) including the building the camera was positioned on would have been completely flattened at that range.
 
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The figure is near enough correct if you take the mass of explosives - 2750 tonnes - but not as regards to explosive force.
 
Minusorange said:
Presume anybody caught in the fireball would be toast rather than pulverised by the shockwave
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There's two effects happening here - There's still a supersonic blastwave infront of the flamefront, which you can't see yet as it's still invisible compared to the later "white dome", and then there's the heat in the fireball. As this happens over a few milliseconds you'd be dead from the supersonic blastwave (initial speed over 7000m/s for 1-3ms dropping to a minimum of 350m/s by 1 second) well before your outer layers get vaporised by the heat (around 1300'c-1500'c inside the fireball) and all this happens before the nerve impulses in your body (120m/s) had reached your brain for it to even begin processing the info in a genuine case of "dead before you knew it".
 
Minusorange said:
So there's a fire, then there's a small explosion with fireworks or munitions cooking off which then leads to the deadly mega explosion ? It'll be interesting to know what exactly happened and what was actually on fire initially
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It's already been noted that welding/burning works were being carried out to the warehouse.
 
I don’t think it’s fire works, I think it’s just the warehouse fire initially spreading to the ammonium nitrate before it detonates. The sparkly stuff isn’t present for long it seems.
 
Dis86 said:
It's already been noted that welding/burning works were being carried out to the warehouse.
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Does AN go all sparkly like that when it's burning before exploding ?

Also why did they have a network of "panic" rooms under the docks ?


I wouldn't be surprised if there wasn't a weapons cache that was initially set on fire which led to the AN reaching conditions to ignite ? Obviously the massive explosion was the AN going up but there's relatively little factual information for what preceded beforehand
 
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