Explosion

An explosion is a sudden increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave.

Natural
Explosions do not commonly occur in nature. Below Earth, most natural explosions arise from volcanic processes of various sorts. Explosive volcanic eruptions occur when magma rising from below has much dissolved gas in it; the reduction of pressure as the magma rises causes the gas to bubble out of solution, resulting in a rapid increase in volume. Explosions also occur as a result of impact events. On other planets, volcanoes and impacts cause explosions with various frequency.

Chemical
The most common artificial explosives are chemical explosives, usually involving a rapid and violent oxidation reaction that produces large amounts of hot gas. Gunpowder was the first explosive to be discovered and put to use. Other notable early developments in chemical explosive technology were Frederick Augustus Abel's development of nitrocellulose in 1865 and Alfred Nobel's invention of dynamite in 1866.

Nuclear
A nuclear weapon is a type of explosive weapon that derives its destructive force from the nuclear reaction of fission or from a combination of fission and fusion. As a result, even a nuclear weapon with a small yield is significantly more powerful than the largest conventional explosives available, with a single weapon capable of destroying an entire city.

Electrical
A high current electrical fault can create an electrical explosion by forming a high energy electrical arc which rapidly vaporizes metal and insulation material. Also, excessive magnetic pressure within an ultra-strong electromagnet can cause a magnetic explosion.

Vapour
Boiling liquid expanding vapour explosions are a type of explosion that can occur when a vessel containing a pressurized liquid is ruptured, causing a rapid increase in volume as the liquid evaporates.

Astronomical
Solar flares are an example of explosion common on the Sun, and presumably on most other stars as well. The energy source for solar flare activity comes from the tangling of magnetic field lines resulting from the rotation of the Sun's conductive plasma.

Mechanical
Strictly a physical process, as opposed to chemical or nuclear, eg, a the bursting of a sealed or partially-sealed container under internal pressure is often referred to as a 'mechanical explosion'. Examples include an overheated boiler or a simple tin can of beans tossed into a fire. A BLEVE (see above) is one type of mechanical explosion, but depending on the contents of the container, the effects can be dramatically more serious - consider a propane tank in the midst of a fire. In such a case, to the limited effects of the simple mechanical explosion when the tank fails are added the chemical explosion resulting from the released (initially liquid and then almost instanteaously gaseous) propane in the presence of an ignition source. For this reason, emergency workers often differentiate between the two events.

Among the largest known explosions in the universe are supernovae, which result from stars exploding, and gamma ray bursts, whose nature is still in some dispute.

Chemical explosions

 * Nanaimo mine explosion 1887
 * Halifax Explosion 1917
 * Battle of Messines 1917
 * Oppau explosion, Ludwigshafen, Germany 1921
 * Bombay Blasts 1944
 * Port Chicago disaster 1944
 * RAF Fauld explosion 1944
 * Texas City Disaster 1947
 * Nedelin catastrophe 1960
 * Soviet N1 rocket explosion 1969
 * Flixborough disaster 1974
 * PEPCON disaster, Henderson, Nevada 1988
 * Ryongchon disaster 2004
 * Hertfordshire Oil Storage Terminal 2005
 * Albania explosion Gerdec 2008

Nuclear testing

 * Trinity test
 * Castle Bravo
 * Tsar Bomba

Use in war

 * Atomic bombings of Hiroshima and Nagasaki

Exploding volcanoes

 * Santorini
 * Krakatoa
 * Mount St. Helens
 * Mount Tambora
 * Mount Pinatubo
 * Yellowstone Caldera