Massive explosion reported in Chinese city of Tianjin

[Cosmos]

https://homment.com/China-Tianjin-Explosion-mindestens-3000tTNT-nuklear-nicht-21t

This article calculates ca. 4400 t-TNT based on the crater diameter of ca. 90 meters. Used formula from study: "Craters produced by explosions on the soil surface" http://cimec.org.ar/ojs/index.php/mc/article/viewFile/713/675 . Haven't verified myself.

Well, all I can say is, that it does not look/feel like a 21 tons explosion. That was actually also my first impression when I heard that number, looked at the explosions and compared them with other explosions in which the TNT tons count of the explosion is known.

 

[Niall]

I think that's because the image on the left (site damage) is superimposed on the same image shown right (see attached).

How sure are we that the two synch up correctly?

Answering my own question, I've checked Google Earth, compared nearby structures using photos of the damaged area, and agree that those two images synch up well. My own approximation of the crater is attached. So it's located in what appeared to be a relatively sparse section of parking lot.

 

[Eboard10]

_http://www.ibtimes.co.in/photos/aerial-photos-huge-crater-400-metres-wide-found-tianjin-blast-site-3738-slide-27358

Crater at Tianjin Blast site has a depth of 7.5 metres & a width of 400 metres.
credit: News.CN

But 400m wide seems to be way to large, if the photo analysis that Data posted is right.

It's likely a plain mistake on their part. From Data's image analysis, it looks like they might be reporting the blast width rather than the crater itself.

 

[Joe]

But 400m wide seems to be way to large, if the photo analysis that Data posted is right.

Maybe 400m is too much but it certainly looks like more than 100m to me.

 

[Mal7]

I think the lower of the grey buildings (to the left of the crater in some of the photos, the building that didn't get it's roof blown off, and that has another building with the roof missing parallel to it) is about 35.2m in length from the Scale Key on Google Earth.

The crater, measuring from the edge of the water line, seems to be about 1.92 times the length of that building in the longer dimension, and about 1.81 times that building's length in the other dimension.

So I would estimate the crater is about 68 x 64m, or roughly 66m in diameter. (Or more if you count disturbed ground outside the water area as being part of the crater.)

 

[Gary]

https://homment.com/China-Tianjin-Explosion-mindestens-3000tTNT-nuklear-nicht-21t

This article calculates ca. 4400 t-TNT based on the crater diameter of ca. 90 meters. Used formula from study: "Craters produced by explosions on the soil surface" http://cimec.org.ar/ojs/index.php/mc/article/viewFile/713/675 . Haven't verified myself.

Well, all I can say is, that it does not look/feel like a 21 tons explosion. That was actually also my first impression when I heard that number, looked at the explosions and compared them with other explosions in which the TNT tons count of the explosion is known.

I don't know where the figure of 4400t-TNT came from in their calculations.

For the prediction of crater explosion dimensions (TNT) at ground level the paper has two equations (page 14):

D(m) = 0.42 W (kg) and D(m) = 0.61 W (kg)

Say we split the difference and use a figure of 0.5 for this incident. 90 = 0.5 x 180

Therefore, for a 90 metre diameter crater it would take 180 kg of TNT - which is only 0.18 Tonne (metric).

Maths was never my strong subject, so am I missing something here?

When explosions are reported on, it is the "ton of TNT" (measured in joules) that is used I think, so my conversion to metric tonnes may not be accurate.

The TNT equivalent is a method of quantifying the energy released in explosions. The "ton of TNT" is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of a ton of TNT.

https://en.wikipedia.org/wiki/TNT_equivalent

Answering my own question, I've checked Google Earth, compared nearby structures using photos of the damaged area, and agree that those two images synch up well. My own approximation of the crater is attached. So it's located in what appeared to be a relatively sparse section of parking lot.

Very interesting. Provided it was like that at the time of explosion, the crater could only have been formed by a massive blast - from below!

 

[Mal7]

I don't know where the figure of 4400t-TNT came from in their calculations.

For the prediction of crater explosion dimensions (TNT) at ground level the paper has two equations (page 14):

D(m) = 0.42 W (kg) and D(m) = 0.61 W (kg)

Say we split the difference and use a figure of 0.5 for this incident. 90 = 0.5 x 180

Therefore, for a 90 metre diameter crater it would take 180 kg of TNT - which is only 0.18 Tonne (metric).

Maths was never my strong subject, so am I missing something here?

Yes you're missing the cube root from the equation on page 14 (written as a superscript "1/3").

The equations are also on the homment webpage:

Formula for D=diameter vs. W=energy
above ground-explosion : D1 [m] = 0.42W[Kg]^(1/3) oder W[t-TNT] = ( D[m] / 4.2 ) ^ 3
center at/below ground : D2 [m] = 0.61W[Kg]^(1/3) oder W[t-TNT] = ( D[m] / 6.1 ) ^ 3

"^3" means cubed, so energy in tons of TNT = ( Diameter / 6.1 ) cubed.


4405.7 = (100 / 6.1 ) x (100 / 6.1) x (100 / 6.1)

 

[Mikey]

4405.7 = (100 / 6.1 ) x (100 / 6.1) x (100 / 6.1)

So now we have to find out how much volume of a particular substance (the ones claimed) will produce 4400 t TNT explosive power -- and see if they fit into one or several standard shipping containers.

 

[Cosmos]

https://homment.com/China-Tianjin-Explosion-mindestens-3000tTNT-nuklear-nicht-21t

Article in German saying that explosion was 3000t TNT minimum, not just 21t TNT. Also provided is a Google Earth image comparison showing that the crater is located where formerly there was only simple storage of containers. I expected huge chemical facilities there. Unless of course the image comparison is wrong, but some features do indeed match.

Article also says that explosion was very near the National Supercomputer Center:

http://www.epochtimes.de/Mediensperre-ueber-Stadt-der-Toten-Tausende-in-Tianjin-vermisst-a1262105.html

This article in German talks about inofficial numbers of 1400 dead and 700 missing.

The guy just updated his article.

His new measurements say the crater is 95 x 104 meters.

As far as I can gather, he thinks that it is impossible that an equivalent of 21 tons of TNT can explode on the surface (as China claims) and result in a crater of that size. 21 tons would make a crater of about 12 meters width. For an explosion on the surface you would need at least 13500 tons of TNT for a crater of 95 x 104 meters to occur. If the stuff was stored in the underground (which he thinks is unlikely, because of the size of that area) you would need much less tons of TNT, but still about 4400 tons.

So if those calculations resamble reality, it seems to be unlikely that something exploded there, on its own, that was stored on the surface, and resulted in that crater, because you would need so much explosive material there, that it can produce an explosion of 13500 tons of TNT. That would a huge storage area I guess.

If it was stored underground (which seems to be unlikely as well) you would still need to have explosive material that can cause a 4400 tons TNT explosion.

So either there was much more explosive material on the site (which I doubt), then the government tells us, or something in the underground, like gas and such, fueled the explosion. Or something form the air, like a comet or plasma phenomena, fueled it. The guy in the article actually states that a meteorite is possible as well.

To be honest, I still think the bright flash that appeared before the second explosion might be an important piece of the puzzle.

Another interesting point the guy brings up is the fact that quite a number of sources first reported that nuclear experts were send to the site, but later most of those articles and statements were changed and they were not mentioned anymore. Also the 3 kilometer evacuation zone seems to be quite much.

 

[Joe]

4405.7 = (100 / 6.1 ) x (100 / 6.1) x (100 / 6.1)

So now we have to find out how much volume of a particular substance (the ones claimed) will produce 4400 t TNT explosive power -- and see if they fit into one or several standard shipping containers.

Not sure how much of the substance would be needed, but 4.8kt of TNT is equivalent to between a 5.0 and 6.0 magnitude earthquake. They claim that the explosions in Tianjin only registered a 2.3 and 2.9. So something does not compute somewhere. A 2.5 on the Richter scale is equivalent to about 500kgs of TNT.

 

[domi]

I think safety systems are going to need a major overhaul (if that were even possible) given the increasing intensity and variety of explosions around the world we are currently witnessing. For instance, this week a giant crater was left behind after a lightning strike caused an explosion of an underground fuel storage tank in the US - the very fact it is 'underground' was considered a prime safety design factor, which in this case proved wholly ineffective.

As the local Fire Chief said

"I can tell you in my 45 year career, I have never seen anything like this. Underground storage tanks are put there to reduce the potential for fire,"

http://www.sott.net/article/299752-Giant-crater-left-behind-after-lightning-strikes-underground-fuel-tank

All the underground fuel tanks that I know off have some sort of ventilation stack or pressure relief valve so perhaps there was a "charge cloud" above the tank creating a conducting path to the ground through the tank itself.

 

[domi]

Yeah, the fact that the site was storing ammonium nitrate makes it a bit too coincidental to not look back at the West, Texas explosion where ammonium nitrate was also housed. Question is, if it was a meteorite fragment, highly charged, what is it that makes such things attracted to ammonium nitrate??

Ammonium nitrate seems to be an interesting molecule and is poly-ionic.
_http://ammoniumnitrate.weebly.com/structure.html

Maybe that's what makes it special?

 

[Mal7]

His new measurements say the crater is 95 x 104 meters.

I still like my estimate of 64 x 68m, for the area marked by the red line. It was made by downloading Google Earth, zooming in on a building shown in the photos, and measuring the length of the building against the scale bar. Then finally comparing the proportions of the crater area to the length of the building.

If the diameter was more like 66m, this would work out to 1266.7 t TNT using the same formula, or about 1.2 to 1.3 kt of TNT.

 

[Ruth]

We suspect that the real reason for their uncertainty is due to the fact that something natural, but extremely unusual, happened there.

A combination of factors, or so it seems, one igniting the other. I wonder what type of land this area was built on?

 

[angelburst29]

A report of White Foam appearing during first rainstorm after the blast.

First rainfall since Tianjin explosion leaves city covered in mysterious white foam
_http://shanghaiist.com/2015/08/18/first_rainfall_since_tianjin_explos.php

The first rainfall to wash over Tianjin since a series of blasts struck a warehouse in the Binhai district last week has sparked a new wave of concern as an unidentified white foam has appeared on the streets.

Some who made contact with it are reporting a burning sensation on their face and lips, while others are reporting a stinging sensation on their arms. Some have said they experienced an itchy sensation, according to a NetEase News report.

Meteorological experts said Monday that rainfall would no longer pose direct danger to people's health, according to a CCTV News report.

However, authorities had expressed concern that the downpour, aside from hampering rescue efforts, would spread harmful substances across the city, after around 700 tons of sodium cyanide—a toxic chemical that creates a combustable substance when it meets with water—was found at the blast site.

Officials today said that at least 40 types of dangerous chemicals were detected at the blast zone, including 800 tons of ammonium nitrate and 500 tons of potassium nitrate, the Guardian reports.

Bao Jingling, chief engineer for the Tianjin Environmental Protection Bureau, previously said in an NBC News report that "if there is rain, it will produce hydrogen cyanide, so we are monitoring it closely," adding that the military's anti-chemical warfare division had been sent to the site on Sunday and the situation "currently...isn't very serious".

Hydrogen cyanide gas is described by the US Centers for Disease Control and Prevention as being a “rapidly fatal” toxic chemical that can reduce the body's ability to use oxygen.

In preparation for the rain, authorities reportedly built cofferdams around a 100,000-square-meter core area of the explosions which will be continually reinforced to prevent contaminated water from flowing out, Xinhua said.

Local monitoring centers reported a normal air quality reading in the city, and the Tianjin deputy mayor in charge of work safety said at a press conference yesterday that sodium cyanide within a three-kilometer radius of the core blast site would be neutralized by yesterday evening.

A total of 114 people have been confirmed dead with 70 more missing after two huge explosions and one smaller blast ripped through a warehouse storing hazardous materials last Wednesday.