Nowadays we often see explosive events coming from bombs, bomb explosions not only in battle but now we often see bombs targeting innocent civilians, be it bombs made by standard military factories and also homemade bombs. Basically, the explosion is a large amount of energy release event at a narrow volume of space in a short time. The energy can be chemical energy, depressed gas energy or even nuclear energy.
### Low Explosive and High Explosive
Intentional or not an explosion occurs as a result of the combustion of explosive materials or explosives. After the explosion we will soon witness the spreading of shockwaves, the shock wave is one of the effects of the explosion, the invisible strong pressure that exceeds the local atmospheric pressure as a result of a very strong push of explosive gases and plasma to the surrounding air . But before exploring further about shock waves, let us first review the classification of explosives.
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<em><sup>illustration of explosion.<a href="https://www.pexels.com/photo/wood-explosion-fire-hot-8504/">pexels</a></sup></em>
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Based on the initial velocity of the shock wave release, or referred to as blast speed, there are two groups of explosives known. A first group is a group of high explosive or high explosives. He got his name because it has a blasting speed greater than the speed of sound in the air. TATP (tri acetone triperoxide) belongs to this group because its blasting speed is 5.3 km / sec, equivalent to 19,000 km / h. A class with it is the legendary TNT (trinitrotoluene). In addition to being standard for describing explosive energy, TNT is also used as a blend of mixtures to form other high-powered explosives (eg Composition B, Composition H6, Amatol and others). TNT has a blasting speed of 6.9 km/second or the equivalent of 24,800 km / h. For comparison, the speed of sound on the Earth's face at standard temperature and pressure is 'only' 340 meters/sec or equivalent to 1,200 km/hour. The explosive event caused by this explosive group has its own distinctive name: detonation.
<center>https://steemitimages.com/DQmYyRypQyiNuK1coKDFhzx2j5oGzmY7dzknfB2xKH2bJae/image.png</center><center><sup>*Synthesis of tri-cyclic acetone peroxide.,<a href="https://en.wikipedia.org/wiki/Acetone_peroxide#/media/File:Acetone_Peroxide_Synthesis_V.2.svg">wikipedia</a>*</sup></center>
The second group is the low explosive explosive group. So named because it has a blasting speed that is smaller than the speed of sound. This explosive group has blasting speeds ranging from just a few centimeters per second to a maximum of 400 meters/sec. Fireworks powder/fireworks and fireworks also belong to this group. Like detonation, the explosion caused by this explosive group also has its own name: deflagration.
The explosion releases energy that is practically called blast energy. It is expressed in TNT with a standard of 1 kilogram TNT = 4.18 MegaJoule (MJ). If the energy is very large, it can also be expressed in tons of TNT (1 ton TNT = 1,000 kilogram TNT), kiloton TNT (1 kiloton TNT = 1,000 tons TNT) or even megaton TNT (1 megaton TNT = 1,000,000 tons TNT). The biggest explosion ever produced by mankind to date is that of the former Soviet Union in the Tsar Bomba nuclear test (RDS-220) on October 30, 1961. The test of a hydrogen bomb exploded at an altitude of 4,000 meters above sea level ) it releases 50 megatons of TNT energy. Or 2,500 times more powerful than the Hiroshima bomb.
<center>https://steemitimages.com/DQma2AeRJoAyWqXRFSxyuKxvLtStLr4qeyzLwRdrAsCnSxX/image.png</center><center><sup>*Chunks of explosives-grade TNT,<a href="https://en.wikipedia.org/wiki/TNT#/media/File:Trinitrotoluen.JPG">wikipedia</a>*</sup></center>
In general perception, high-powered explosives have secret compositions and are only used in military circles. That's not entirely true. Many high-powered explosives that can be assembled by themselves outside the military. In the bombing of the Oklahoma federal building on April 19, 1995, two suspects Timothy McVeigh and Terry Nichols used materials commonly found in agricultural environments: fertilizer and oil. The explosive 2.2-ton-high explosive explosive device put on the rental truck was so powerful that when it was detonated it released 1.8 tons TNT equivalent energy. The massive explosion killed 169 people and wounded more than 680 people. It also produces a crater width of 8 meters with a depth of 2 meters at the point of explosion, while its shock wave destroys all buildings up to a radius of 500 meters from the point of explosion.
### The Impact of Surge Waves
What if a high powered explosive is in the free air?
<center>https://steemitimages.com/DQmeRCGZW49fjXNdNcxgkzdcbc2aqkwTbW9pW5Sw98qDLUK/image.png</center><center><sup>*Broken windows in the Chelyabinsk Drug Theater foyer impact the shock waves of Chelyabinsk 2013 event in Yemanzhelinsk city (Russia),<a href="https://en.wikipedia.org/wiki/Chelyabinsk_meteor#/media/File:Chelyabinsk_meteor_event_consequences_in_Drama_Theatre.jpg">wikipedia</a>*</sup></center>
The shock wave is the most dominant impact. Shock waves are always formed when any explosive, whether low power or especially high power, is detonated. Shock waves are also always formed in explosive events. Whether starting from industrial accidents such as in the explosion of the Tianjin port complex (China) on August 12, 2015, to the explosive eruption of the volcano. Even the sky events often release shock waves, for example when the meteor collapse in Chelyabinsk (Russia) on February 13, 2013. In the event called Chelyabinsk 2013 event that as many as 7,320 buildings broken glass windows due to shock wave shock. The shards of the windows were flying and wounding the people close by. As a result, 1,613 people were forced to visit the nearest hospital and clinic with iris injuries caused by broken glass shards.
The shock wave is the invisible pressure expressed by the value of over-pressure or overpressure, ie the difference between the shock-wave pressures against standard atmospheric pressure (idealized on the mean sea water level). The overpressure value can range from as small as 200 Pascal (Pa, 1 Pa = 1 Newton / meter2) with the minimal impact that just vibrates the window glass and is likely to crack the lattice. But it could also be 1 MegaPascal (1,000,000 Pa) with a deadly impact on humans, being able to mutilate our bodies mercilessly. Even if its overpressure reaches 2.5 MegaPascal, its impact is capable of perforating the ground and creating a distinctive crater basin. All depends on the distance to the point of explosion. Because overpressure is inversely proportional to the increase in distance and under certain conditions can be inversely proportional to the square of the distance from the point of explosion.
The passage of shock waves causes the points to pass to have greater air pressure than the surrounding environment for a moment. And the difference in air pressure causes the wind to blow. So the propagation of the shock wave followed by the wind blow from the direction of the explosion points out. The strong weakness of the blast caused by the explosion depends on the size of the overpressure that occurred. Then he can blow at a speed of only 13 km / h (on overpressure 200 Pascal). But it can also be as fast as more than 2,200 km / h (on overpressure 1 MegaPascal).
The same equations are widely applied in evaluating the impact of shock waves from explosions either from conventional high explosives even to nuclear explosives. Here it is assumed that the TATP explosive energy is equivalent to 3 kg TNT. Another assumption, the height of the explosion point is 1 meter from the ground level, or in accordance with the waist height of the average adult human standing.
The results are amazing. In a distance of 18 meters, shockwave explosion TATP 3 kilograms produce overpressure of 8,500 Pascal whose impact is able to knock people standing upright. Of course, the person will fall into a loud thump so that it follows a broken bone in various places and a possible concussion. Within 25 meters, the overpressure is still 5,500 Pascal so that the window glass can still be contrived. Even more terrible, these shards of glass window will then be taken with high speed like a bullet to a distance of 54 meters. People within this range can suffer penetrating injuries like bullets. Until the distance of 82 meters, window glass can still be broken partly due to an overpressure of 1,200 Pascal. The person who happens to be nearby can get an iris wound. Even up to 432 meters distance, the edge of the window glass can still be contrived cracked due to an overpressure of 200 Pascal.
How does it affect people? The above description shows that if you stand up to 25 meters away from the explosive point, then you will most likely die. Both due to falling very hard (especially if not handled immediately) and bombarded by an abysmal amount of glass that ran as fast as a bullet, like a mitraliur fire. If you stand at a distance of 50 meters, you will still be injured (moderate to severe) due to bursts of debris. And at a distance of 82 meters, you will still get hurt (lightly) especially if it is near the window.
<center>https://steemitimages.com/DQmT4NuyzHHsZtuT6Lq61f4bG2JZmqzrih5uHK2r8twdfyo/image.png</center><center><sup>*illustration of bomb explosion,<a href="https://www.pexels.com/photo/grayscale-photo-of-explosion-on-the-beach-73909/">pexels</a>*</sup></center>
It should be underlined that this calculation is done in ideal conditions with an open-air explosion point without secondary charge. If spikes and iron balls are included, then when TATP explodes its shockwave will push the spikes and the iron balls shot at high speed like a bullet. They can go as far as 100 meters from the explosion point. It is clear that if there is someone standing within a distance of fewer than 100 meters from the point of explosion. he could suffer penetrating injuries and puncture wounds as if exposed to bullet rifles. The severity of this type of wound is higher than the wound caused by a breaking or slice of broken glass. So it can be said that the addition of secondary payload makes the bomb destroyed more power.
Secondary loads in the form of metal scraps are often encountered in military weaponry. For example in anti-aircraft missile systems, which supply pieces of metal with certain geometries to penetrate the fuselage. So the target plane will remain heavily damaged and fall out of pieces by high-speed pieces of metal even though the missile exploded within a certain distance, say 10 meters, from the plane. This type of missile is the day that dropped the Boeing-777 aircraft Malaysia Airlines flight MH17 in eastern Ukraine.
It can be seen that with the results of the calculation of the impact of shock waves, the police statement that the TATP 3-kilogram-based explosive assemblies could impact up to 300 meters from the explosion point is not excessive. So the pressure cooker bomb was not a toy bomb, not a beam. The impact can be terrible. Especially if the secondary load, such as spikes and buckwheat, also installed. Because when detonation occurs, the secondary charge will skyrocket as fast as a bullet. Distance 150 meters from the explosion point is not necessarily safe.
### Comparison
Some of us have tried to compare the ability of this TATP 3 kilogram with heavy-duty bombs like MOAB and FOAB. It is said that the impact of the explosion of the MOAB bomb was 150 meters while the impact of the FOAB explosion reached 300 meters. Though the weight is much smaller than the MOAB (11 tons TNT) and FOAB (44 tons TNT). The impossible, they concluded.
***What is the real comparison?***
The MOAB bomb (Mother of All Bombs) has the official name GBU-43 / B Massive Ordnance Air Blast. This is a type of clever bomb or bomb guided to a specific target without an active driver (GBU = guided bomb unit) which also functions as a psychological bomb, a weapon for leveling forested land and a bombing of minefields. The United States (US) developed a 10,300-kilogram heavyweight bomb with the 8,500-kilogram Composition H6 weighing it in 2003 as a substitute for the lighter bombs (BLU-82 Daisy Cutter). Currently, in the US military arsenal, there are only 15 units of MOAB bombs.
With an energy content of 11 tons TNT, the MOAB bomb has a blast radius of 150 meters. The blast radius is a radius where severe damage and total damage due to the blast wave blast occur. In this blast radius, the trees in the forest will fall, and the mines planted in the minefield will explode due to overpressure (21,700 Pascal).
The FOAB (Father of All Bombs) bomb was developed by the Russian military since 2007 under the official name of ATBIP (Aviation Thermobaric Bomb of Increased Power). It is also a smart bomb and psychological bombs that principally thrust (using oxygen in the air) weighing 9,000 pounds. With a 44-ton TNer energy content, this heavy-duty bomb has a blast radius of 300 meters. In contrast to MOAB, there are currently 100 FOAB bombs in the Russian military arsenal as well as making it the strongest non-nuclear bomb ever.
<center>https://steemitimages.com/DQmQezwMdGR94pBe6rUC86ndVRYPSkiEP7U4JXi7RR1YWS9/image.png</center><center><sup>*illustration of bomb explosion,<a href="https://www.pexels.com/photo/fireman-holding-hose-during-daytime-155901/">pexels</a>*</sup></center>
What is the impact of shock wave product shock? Calculations on the MOAB bomb with the assumption of a 1-meter high explosive point and an explosion in the open air showed the explosion of this bomb creating a blast radius up to a distance of 150 meters from the explosive point. Furthermore, he was able to knock someone who stood 276 meters from the explosive point. Shock waves also can still crush window glass at a distance of 376 meters from the explosion point. Furthermore, its shock waves are still capable of spreading debris as far as 821 meters from the explosive point. Even the shock waves are still able to crack the window glass which is located as far as 6670 meters from the point of explosion.
The same thing applies also to FOAB bombs. It should only be underscored that the explosive bombs produce shock waves with the longer duration than non-thrust bombs. So that the radius of the shock wave effect of the explosive bomb explosion will be greater. This is seen from his blast radius. The calculation of the impact of the FOAB bomb waves with the assumption of a 1-meter high explosive point and the explosion in the open air shows its blast radius (ie, overpressure 21,700 Pascal) up to 240 meters from the explosion point. But in practice, the blast radius of FOAB bomb is 300 meters. So there is a multiplication factor (digger) of 1.25. Taking this into consideration, it can be calculated that a person who stands 548 meters from the point of the explosion will crash violently. Shock waves are still capable of crushing glass windows at a distance of 745 meters from the explosive point. Shock waves are also still capable of spreading debris as far as 1,629 meters from the explosive point. The weakest impact, namely the cracking of window glass due to exposure to shock waves, will occur up to a distance of 13,214 meters from the explosive point.
But there are almost as many homemade explosives that have been previously dehydrated in the past. Come to Beirut (Lebanon) in 1983, the beautiful country of the time of Kahlil Gibran but torn from anger between 1975 and 1990. So much so in a burning rage that once in a while the population of Beirut kept more grenade stocks than umbrellas. It was in the midst of this chaos on October 23, 1983, that a 19-ton truck drove past the Beirut international airport complex. He moved toward Hilton Beirut, the unofficial name for the 8th US Marines Battalion's headquarters that were part of the international peacekeeping force in Lebanon. After forcing into the compound by crashing barbed wire surrounding the headquarters, the truck stopped right in the lobby of the 4-story building. The driver, part of the Hezbollah militia, then pressed the death button.
<center>https://steemitimages.com/DQmPBvTTmdgn6YXMDLgQ3Kg9EZWHkKRBsckzTppQwcMRErd/image.png</center><center><sup>*illustration of bomb explosion,<a href="https://www.pexels.com/photo/fire-hell-inferno-flame-9328/">pexels</a>*</sup></center>
The explosion was awesome. The thermally-lit explosive device releases 9.5 tons of TNT's equivalent, the largest non-nuclear explosion ever since the end of World War 2. The blast created a 10-meter wide crater. All parts of the truck disappear without any trace, except the engine block alone. The Hilton Beirut building was a crumbly pileup, like lifted into the air to then slam very hard to the ground. 242 people in it consisting of 220 Marines, 18 sailors, 3 soldiers and 1 civilian immediately dying, while 128 others suffered severe injuries. Among the wounded, 13 were eventually killed. So the total death toll reached 255 people. This is the biggest loss of life experienced by US Marines since the battle of Iwo Jima (January 1945 TU) in World War 2. This homemade explosive detonation was the main factor driving Ronald Reagan, then US President, to withdraw his entire army from Lebanon without exception.
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### REFERENCE :
https://www.britannica.com/technology/explosive
http://www.forensicsciencesimplified.org/explosives/glossary.html
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https://www.britannica.com/science/trinitrotoluene
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https://www.theguardian.com/science/2013/nov/06/chelyabinsk-meteor-russia
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https://i-hls.com/archives/17637
https://www.history.com/this-day-in-history/beirut-barracks-blown-up