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113-413: For an explosion to occur, there must be a rapid, forceful expansion of matter. There are numerous ways this can happen, both naturally and artificially, such as volcanic eruptions , or two objects striking each other at very high speeds, as in an impact event . Explosive volcanic eruptions occur when magma rises from below, it has dissolved gas in it. The reduction of pressure as the magma rises causes

226-443: A shaped charge the explosive forces are focused to produce a greater local explosion; shaped charges are often used by military to breach doors or walls. The speed of the reaction is what distinguishes an explosive reaction from an ordinary combustion reaction. Unless the reaction occurs very rapidly, the thermally expanding gases will be moderately dissipated in the medium, with no large differential in pressure and no explosion. As

339-491: A ghost town ) and Fourpeaked Mountain in Alaska, which, before its September 2006 eruption, had not erupted since before 8000 BCE. Propane Propane ( / ˈ p r oʊ p eɪ n / ) is a three- carbon alkane with the molecular formula C 3 H 8 . It is a gas at standard temperature and pressure , but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it

452-403: A magnetic explosion . Strictly a physical process, as opposed to chemical or nuclear, e.g., the bursting of a sealed or partially sealed container under internal pressure is often referred to as an explosion. Examples include an overheated boiler or a simple tin can of beans tossed into a fire. Boiling liquid expanding vapor explosions are one type of mechanical explosion that can occur when

565-886: A mid-ocean ridge , such as the Mid-Atlantic Ridge , has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift , the Wells Gray-Clearwater volcanic field , and the Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from

678-512: A nuclear weapon . Explosions frequently occur during bushfires in eucalyptus forests where the volatile oils in the tree tops suddenly combust. Among the largest known explosions in the universe are supernovae , which occur after the end of life of some types of stars . Solar flares are an example of common, much less energetic, explosions on the Sun, and presumably on most other stars as well. The energy source for solar flare activity comes from

791-413: A boost, where it is added through the turbocharger, to mix with diesel fuel droplets. Propane droplets' very high hydrogen content helps the diesel fuel to burn hotter and therefore more completely. This provides more torque, more horsepower, and a cleaner exhaust for the trucks. It is normal for a 7-liter medium-duty diesel truck engine to increase fuel economy by 20 to 33 percent when a propane boost system

904-457: A chimney, (known as lower heating value ) is −2043.455 kJ/mol. The lower heat value is the amount of heat available from burning the substance where the combustion products are vented to the atmosphere; for example, the heat from a fireplace when the flue is open. The density of propane gas at 25 °C (77 °F) is 1.808 kg/m , about 1.5× the density of air at the same temperature. The density of liquid propane at 25 °C (77 °F)

1017-456: A gas, very high pressure is required to store useful quantities. This poses the hazard that, in an accident, just as with any compressed gas cylinder (such as a CO 2 cylinder used for a soda concession) a CNG cylinder may burst with great force, or leak rapidly enough to become a self-propelled missile. Therefore, CNG is much less efficient to store than propane, due to the large cylinder volume required. An alternative means of storing natural gas

1130-437: A graduated spectrum, with much overlap between categories, and does not always fit neatly into only one of these three separate categories. The USGS defines a volcano as "erupting" whenever the ejection of magma from any point on the volcano is visible, including visible magma still contained within the walls of the summit crater. While there is no international consensus among volcanologists on how to define an active volcano,

1243-679: A merger signal of about 100 ms duration, during which time is it estimated to have radiated away nine solar masses in the form of gravitational energy. 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 invented 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. Chemical explosions (both intentional and accidental) are often initiated by an electric spark or flame in

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1356-443: A paper was published suggesting a new definition for the word 'volcano' that includes processes such as cryovolcanism . It suggested that a volcano be defined as 'an opening on a planet or moon's surface from which magma , as defined for that body, and/or magmatic gas is erupted.' This article mainly covers volcanoes on Earth. See § Volcanoes on other celestial bodies and cryovolcano for more information. The word volcano

1469-469: A popular choice for barbecues and portable stoves because its low −42 °C boiling point makes it vaporise inside pressurised liquid containers (it exists in two phases, vapor above liquid). It retains its ability to vaporise even in cold weather, making it better-suited for outdoor use in cold climates than alternatives with higher boiling points like butane. LPG powers buses, forklifts, automobiles, outboard boat motors, and ice resurfacing machines , and

1582-401: 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 completely destroying an entire city. Explosive force is released in a direction perpendicular to the surface of the explosive. If a grenade is in mid air during the explosion, the direction of the blast will be 360°. In contrast, in

1695-399: A significant risk of fire or explosion. Vendors and advocates of hydrocarbon refrigerants argue against such bans on the grounds that there have been very few such incidents relative to the number of vehicle air conditioning systems filled with hydrocarbons. Propane is also instrumental in providing off-the-grid refrigeration, as the energy source for a gas absorption refrigerator and

1808-537: A small portion of the mass of the explosive material. A material in which the first three factors exist cannot be accepted as an explosive unless the reaction can be made to occur when needed. Fragmentation is the accumulation and projection of particles as the result of a high explosives detonation. Fragments could originate from: parts of a structure (such as glass , bits of structural material , or roofing material), revealed strata and/or various surface-level geologic features (such as loose rocks , soil , or sand ),

1921-407: A vessel containing a pressurized liquid is ruptured, causing a rapid increase in volume as the liquid evaporates. Note that the contents of the container may cause a subsequent chemical explosion, the effects of which can be dramatically more serious, such as a propane tank in the midst of a fire. In such a case, to the effects of the mechanical explosion when the tank fails are added the effects from

2034-422: A visible flame. The enthalpy of combustion of propane gas where all products return to standard state, for example where water returns to its liquid state at standard temperature (known as higher heating value ), is (2,219.2 ± 0.5) kJ/mol, or (50.33 ± 0.01) MJ/kg. The enthalpy of combustion of propane gas where products do not return to standard state, for example where the hot gases including water vapor exit

2147-632: A volcano is largely determined by the composition of the lava it erupts. The viscosity (how fluid the lava is) and the amount of dissolved gas are the most important characteristics of magma, and both are largely determined by the amount of silica in the magma. Magma rich in silica is much more viscous than silica-poor magma, and silica-rich magma also tends to contain more dissolved gases. Lava can be broadly classified into four different compositions: Mafic lava flows show two varieties of surface texture: ʻAʻa (pronounced [ˈʔaʔa] ) and pāhoehoe ( [paːˈho.eˈho.e] ), both Hawaiian words. ʻAʻa

2260-555: A volcano is of a conical mountain, spewing lava and poisonous gases from a crater at its summit; however, this describes just one of the many types of volcano. The features of volcanoes are varied. The structure and behaviour of volcanoes depend on several factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have landscape features such as massive plateaus . Vents that issue volcanic material (including lava and ash ) and gases (mainly steam and magmatic gases) can develop anywhere on

2373-465: A volcano that has experienced one or more eruptions that produced over 1,000 cubic kilometres (240 cu mi) of volcanic deposits in a single explosive event. Such eruptions occur when a very large magma chamber full of gas-rich, silicic magma is emptied in a catastrophic caldera -forming eruption. Ash flow tuffs emplaced by such eruptions are the only volcanic product with volumes rivalling those of flood basalts . Supervolcano eruptions, while

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2486-640: A wood fire burns in a fireplace, for example, there certainly is the evolution of heat and the formation of gases, but neither is liberated rapidly enough to build up a sudden substantial pressure differential and then cause an explosion. This can be likened to the difference between the energy discharge of a battery , which is slow, and that of a flash capacitor like that in a camera flash, which releases its energy all at once. The generation of heat in large quantities accompanies most explosive chemical reactions. The exceptions are called entropic explosives and include organic peroxides such as acetone peroxide . It

2599-438: Is 0.493 g/cm , which is equivalent to 4.11 pounds per U.S. liquid gallon or 493 g/L. Propane expands at 1.5% per 10 °F. Thus, liquid propane has a density of approximately 4.2 pounds per gallon (504 g/L) at 60 °F (15.6 °C). As the density of propane changes with temperature, this fact must be considered every time when the application is connected with safety or custody transfer operations. Propane

2712-739: Is a volcanic field of over 60 cinder cones. Based on satellite images, it has been suggested that cinder cones might occur on other terrestrial bodies in the Solar system too; on the surface of Mars and the Moon. Stratovolcanoes (composite volcanoes) are tall conical mountains composed of lava flows and tephra in alternate layers, the strata that gives rise to the name. They are also known as composite volcanoes because they are created from multiple structures during different kinds of eruptions. Classic examples include Mount Fuji in Japan, Mayon Volcano in

2825-415: Is a popular choice for barbecues and portable stoves because the low boiling point of −42 °C (−44 °F) makes it vaporize as soon as it is released from its pressurized container. Therefore, no carburetor or other vaporizing device is required; a simple metering nozzle suffices. Blends of pure, dry "isopropane" [isobutane/propane mixtures of propane (R-290) and isobutane (R-600a)] can be used as

2938-486: Is a simple asphyxiant . Unlike natural gas , it is denser than air. It may accumulate in low spaces and near the floor. When abused as an inhalant , it may cause hypoxia (lack of oxygen), pneumonia , cardiac failure or cardiac arrest . Propane has low toxicity since it is not readily absorbed and is not biologically active . Commonly stored under pressure at room temperature, propane and its mixtures will flash evaporate at atmospheric pressure and cool well below

3051-422: Is absorbed during the formation of the compound from its elements; such a reaction is called an endothermic reaction. In explosive technology only materials that are exothermic —that have a net liberation of heat and have a negative heat of formation—are of interest. Reaction heat is measured under conditions either of constant pressure or constant volume. It is this heat of reaction that may be properly expressed as

3164-524: Is as a cryogenic liquid in an insulated container as liquefied natural gas (LNG). This form of storage is at low pressure and is around 3.5 times as efficient as storing it as CNG. Unlike propane, if a spill occurs, CNG will evaporate and dissipate because it is lighter than air. Propane is much more commonly used to fuel vehicles than is natural gas, because that equipment costs less. Propane requires just 1,220 kilopascals (177 psi) of pressure to keep it liquid at 37.8 °C (100 °F). Propane

3277-412: Is characterized by a rough, clinkery surface and is the typical texture of cooler basalt lava flows. Pāhoehoe is characterized by its smooth and often ropey or wrinkly surface and is generally formed from more fluid lava flows. Pāhoehoe flows are sometimes observed to transition to ʻaʻa flows as they move away from the vent, but never the reverse. More silicic lava flows take the form of block lava, where

3390-581: Is commonly used for camping and recreational vehicles. It has also been proposed to use propane as a refrigerant in heat pumps . Since it can be transported easily, it is a popular fuel for home heat and backup electrical generation in sparsely populated areas that do not have natural gas pipelines. In June 2023, Stanford researchers found propane combustion emitted detectable and repeatable levels of benzene that in some homes raised indoor benzene concentrations above well-established health benchmarks. The research also shows that gas and propane fuels appear to be

3503-454: Is delivered to end-users via small or medium-sized individual cylinders, while empty cylinders are removed for refilling at a central location. There are also community propane systems, with a central cylinder feeding individual homes. In the U.S., over 190,000 on-road vehicles use propane, and over 450,000 forklifts use it for power. It is the third most popular vehicle fuel in the world, behind gasoline and diesel fuel . In other parts of

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3616-565: Is derived from the name of Vulcano , a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan , the god of fire in Roman mythology . The study of volcanoes is called volcanology , sometimes spelled vulcanology . According to the theory of plate tectonics, Earth's lithosphere , its rigid outer shell, is broken into sixteen larger and several smaller plates. These are in slow motion, due to convection in

3729-584: Is expressed using the volcanic explosivity index (VEI), which ranges from 0 for Hawaiian-type eruptions to 8 for supervolcanic eruptions. As of December 2022 , the Smithsonian Institution 's Global Volcanism Program database of volcanic eruptions in the Holocene Epoch (the last 11,700 years) lists 9,901 confirmed eruptions from 859 volcanoes. The database also lists 1,113 uncertain eruptions and 168 discredited eruptions for

3842-467: Is far less than current refrigerants, propane was chosen as one of five replacement refrigerants approved by the EPA in 2015, for use in systems specially designed to handle its flammability. Such substitution is widely prohibited or discouraged in motor vehicle air conditioning systems, on the grounds that using flammable hydrocarbons in systems originally designed to carry non-flammable refrigerant presents

3955-424: Is formed from its constituents, heat may either be absorbed or released. The quantity of heat absorbed or given off during transformation is called the heat of formation . Heats of formations for solids and gases found in explosive reactions have been determined for a temperature of 25 °C and atmospheric pressure, and are normally given in units of kilojoules per gram-molecule. A positive value indicates that heat

4068-544: Is known as a BLEVE or boiling liquid expanding vapor explosion . The Kingman Explosion involved a railroad tank car in Kingman, Arizona, U.S., in 1973 during a propane transfer. The fire and subsequent explosions resulted in twelve fatalities and numerous injuries. Propane is produced as a by-product of two other processes, natural gas processing and petroleum refining . The processing of natural gas involves removal of butane , propane, and large amounts of ethane from

4181-457: Is much cleaner than that of coal or unleaded gasoline. Propane's per-BTU production of CO 2 is almost as low as that of natural gas. Propane burns hotter than home heating oil or diesel fuel because of the very high hydrogen content. The presence of C–C bonds , plus the multiple bonds of propylene and butylene , produce organic exhausts besides carbon dioxide and water vapor during typical combustion. These bonds also cause propane to burn with

4294-525: Is not suited for most vehicle fuels. HD-5 is a specification that establishes a maximum concentration of 5% propene in propane. Propane and other LP gas specifications are established in ASTM D-1835. All propane fuels include an odorant , almost always ethanethiol , so that the gas can be smelled easily in case of a leak. Propane as HD-5 was originally intended for use as vehicle fuel. HD-5 is currently being used in all propane applications. Typically in

4407-726: Is often a constituent of liquefied petroleum gas (LPG), which is commonly used as a fuel in domestic and industrial applications and in low-emissions public transportation; other constituents of LPG may include propylene , butane , butylene , butadiene , and isobutylene . Discovered in 1857 by the French chemist Marcellin Berthelot , it became commercially available in the US by 1911. Propane has lower volumetric energy density than gasoline or coal, but has higher gravimetric energy density than them and burns more cleanly. Propane gas has become

4520-537: Is one of the several tuyas in the area of the Tuya River and Tuya Range in northern British Columbia. Tuya Butte was the first such landform analysed and so its name has entered the geological literature for this kind of volcanic formation. The Tuya Mountains Provincial Park was recently established to protect this unusual landscape, which lies north of Tuya Lake and south of the Jennings River near

4633-741: Is present for complete combustion, carbon monoxide , soot ( carbon ), or both, are formed as well: C 3 H 8 + 9 2 O 2 ⟶ 2 CO 2 + CO + 4 H 2 O + heat {\displaystyle {\ce {C3H8 + 9/2 O2 -> 2 CO2 + CO + 4 H2O + heat}}} C 3 H 8 + 2 O 2 ⟶ 3 C + 4 H 2 O + heat {\displaystyle {\ce {C3H8 + 2 O2 -> 3 C + 4 H2O + heat}}} The complete combustion of propane produces about 50 MJ/kg of heat. Propane combustion

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4746-519: Is rated HD-5 (Heavy Duty 5%). HD-5 grade has a maximum of 5 percent butane, but propane sold in Europe has a maximum allowable amount of butane of 30 percent, meaning it is not the same fuel as HD-5. The LPG used as auto fuel and cooking gas in Asia and Australia also has very high butane content. Propylene (also called propene) can be a contaminant of commercial propane. Propane containing too much propene

4859-537: Is that theft is much more difficult than with gasoline or diesel fuels. Propane is also used as fuel for small engines , especially those used indoors or in areas with insufficient fresh air and ventilation to carry away the more toxic exhaust of an engine running on gasoline or diesel fuel. More recently, there have been lawn-care products like string trimmers , lawn mowers and leaf blowers intended for outdoor use, but fueled by propane in order to reduce air pollution . Many heavy-duty highway trucks use propane as

4972-407: Is the rapid liberation of heat that causes the gaseous products of most explosive reactions to expand and generate high pressures . This rapid generation of high pressures of the released gas constitutes the explosion. The liberation of heat with insufficient rapidity will not cause an explosion. For example, although a unit mass of coal yields five times as much heat as a unit mass of nitroglycerin ,

5085-471: Is typically low in silica, shield volcanoes are more common in oceanic than continental settings. The Hawaiian volcanic chain is a series of shield cones, and they are common in Iceland , as well. Lava domes are built by slow eruptions of highly viscous lava. They are sometimes formed within the crater of a previous volcanic eruption, as in the case of Mount St. Helens , but can also form independently, as in

5198-610: Is used for heat and cooking in recreational vehicles and campers . Propane is becoming popular as a replacement refrigerant (R290) for heatpumps also as it offers greater efficiency than the current refrigerants: R410A / R32, higher temperature heat output and less damage to the atmosphere for escaped gasses - at the expense of high gas flammability. Propane was first synthesized by the French chemist Marcellin Berthelot in 1857 during his researches on hydrogenation . Berthelot made propane by heating propylene dibromide (C 3 H 6 Br 2 ) with potassium iodide and water. Propane

5311-474: Is used. It is cheaper because propane is much cheaper than diesel fuel. The longer distance a cross-country trucker can travel on a full load of combined diesel and propane fuel means they can maintain federal hours of work rules with two fewer fuel stops in a cross-country trip. Truckers, tractor pulling competitions, and farmers have been using a propane boost system for over forty years in North America. The North American standard grade of automotive-use propane

5424-617: The Cascade Volcanoes or the Japanese Archipelago , or the eastern islands of Indonesia . Hotspots are volcanic areas thought to be formed by mantle plumes , which are hypothesized to be columns of hot material rising from the core-mantle boundary. As with mid-ocean ridges, the rising mantle rock experiences decompression melting which generates large volumes of magma. Because tectonic plates move across mantle plumes, each volcano becomes inactive as it drifts off

5537-569: The Tunguska event of 1908 is believed to have resulted from a meteor air burst . Black hole mergers, likely involving binary black hole systems, are capable of radiating many solar masses of energy into the universe in a fraction of a second, in the form of a gravitational wave . This is capable of transmitting ordinary energy and destructive forces to nearby objects, but in the vastness of space, nearby objects are rare. The gravitational wave observed on 21 May 2019, known as GW190521 , produced

5650-755: The core–mantle boundary , 3,000 kilometres (1,900 mi) deep within Earth. This results in hotspot volcanism , of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide past one another. Large eruptions can affect atmospheric temperature as ash and droplets of sulfuric acid obscure the Sun and cool Earth's troposphere . Historically, large volcanic eruptions have been followed by volcanic winters which have caused catastrophic famines. Other planets besides Earth have volcanoes. For example, volcanoes are very numerous on Venus. Mars has significant volcanoes. In 2009,

5763-834: The landform and may give rise to smaller cones such as Puʻu ʻŌʻō on a flank of Kīlauea in Hawaii. Volcanic craters are not always at the top of a mountain or hill and may be filled with lakes such as with Lake Taupō in New Zealand. Some volcanoes can be low-relief landform features, with the potential to be hard to recognize as such and be obscured by geological processes. Other types of volcano include cryovolcanoes (or ice volcanoes), particularly on some moons of Jupiter , Saturn , and Neptune ; and mud volcanoes , which are structures often not associated with known magmatic activity. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes except when

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5876-643: The space group P2 1 /n. The low space-filling of 58.5% (at 90 K), due to the bad stacking properties of the molecule, is the reason for the particularly low melting point. Propane undergoes combustion reactions in a similar fashion to other alkanes . In the presence of excess oxygen, propane burns to form water and carbon dioxide . C 3 H 8 + 5 O 2 ⟶ 3 CO 2 + 4 H 2 O + heat {\displaystyle {\ce {C3H8 + 5 O2 -> 3 CO2 + 4 H2O + heat}}} When insufficient oxygen

5989-442: The "heat of explosion." A chemical explosive is a compound or mixture which, upon the application of heat or shock, decomposes or rearranges with extreme rapidity, yielding much gas and heat. Many substances not ordinarily classed as explosives may do one, or even two, of these things. A reaction must be capable of being initiated by the application of shock, heat, or a catalyst (in the case of some explosive chemical reactions) to

6102-510: The 1930s included the introduction of railroad tank car transport, gas odorization, and the construction of local bottle-filling plants. The year 1945 marked the first year that annual LP gas sales reached a billion gallons. By 1947, 62% of all U.S. homes had been equipped with either natural gas or propane for cooking. In 1950, 1,000 propane-fueled buses were ordered by the Chicago Transit Authority , and by 1958, sales in

6215-605: The December 2015 EIA figure for the East Coast at $ 2.67 per gallon and the Midwest at $ 1.43 per gallon. As of August 2018 , the average US propane retail cost was approximately $ 2.48 per gallon. The wholesale price of propane in the U.S. always drops in the summer as most homes do not require it for home heating. The wholesale price of propane in the summer of 2018 was between 86 cents to 96 cents per U.S. gallon, based on

6328-541: The Energy Information Administration (EIA) quotes a $ 2.995 per gallon average on the East Coast for October 2013, while the figure for the Midwest was $ 1.860 for the same period. As of December 2015 , the propane retail cost was approximately $ 1.97 per gallon, which meant filling a 500-gallon propane tank to 80% capacity costed $ 788, a 16.9% decrease or $ 160 less from November 2013. Similar regional differences in prices are present with

6441-622: The Philippines, and Mount Vesuvius and Stromboli in Italy. Ash produced by the explosive eruption of stratovolcanoes has historically posed the greatest volcanic hazard to civilizations. The lavas of stratovolcanoes are higher in silica, and therefore much more viscous, than lavas from shield volcanoes. High-silica lavas also tend to contain more dissolved gas. The combination is deadly, promoting explosive eruptions that produce great quantities of ash, as well as pyroclastic surges like

6554-584: The U.S. had reached 7 billion US gallons (26,000,000 m ) annually. In 2004, it was reported to be a growing $ 8-billion to $ 10-billion industry with over 15 billion US gallons (57,000,000 m ) of propane being used annually in the U.S. During the COVID-19 pandemic , propane shortages were reported in the United States due to increased demand. The " prop- " root found in "propane" and names of other compounds with three-carbon chains

6667-613: The USGS defines a volcano as active whenever subterranean indicators, such as earthquake swarms , ground inflation, or unusually high levels of carbon dioxide or sulfur dioxide are present. The USGS defines a dormant volcano as any volcano that is not showing any signs of unrest such as earthquake swarms, ground swelling, or excessive noxious gas emissions, but which shows signs that it could yet become active again. Many dormant volcanoes have not erupted for thousands of years, but have still shown signs that they may be likely to erupt again in

6780-759: The United States and Canada, LPG is primarily propane (at least 90%), while the rest is mostly ethane , propylene , butane , and odorants including ethyl mercaptan . This is the HD-5 standard, (maximum allowable propylene content, and no more than 5% butanes and ethane) defined by the American Society for Testing and Materials by its Standard 1835 for internal combustion engines. Not all products labeled "LPG" conform to this standard, however. In Mexico, for example, gas labeled "LPG" may consist of 60% propane and 40% butane. "The exact proportion of this combination varies by country, depending on international prices, on

6893-432: The availability of components and, especially, on the climatic conditions that favor LPG with higher butane content in warmer regions and propane in cold areas". Propane is bought and stored in a liquid form, LPG. It can easily be stored in a relatively small space. By comparison, compressed natural gas (CNG) cannot be liquefied by compression at normal temperatures, as these are well above its critical temperature . As

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7006-510: The boundary with the Yukon Territory . Mud volcanoes (mud domes) are formations created by geo-excreted liquids and gases, although several processes may cause such activity. The largest structures are 10 kilometres in diameter and reach 700 meters high. The material that is expelled in a volcanic eruption can be classified into three types: The concentrations of different volcanic gases can vary considerably from one volcano to

7119-410: The burning substance into heat released to the surroundings, while in the latter, fast combustion ( i.e. detonation ) instead converts more internal energy into work on the surroundings ( i.e. less internal energy converted into heat); c.f. heat and work (thermodynamics) are equivalent forms of energy. See Heat of Combustion for a more thorough treatment of this topic. When a chemical compound

7232-402: The case of Lassen Peak . Like stratovolcanoes, they can produce violent, explosive eruptions, but the lava generally does not flow far from the originating vent. Cryptodomes are formed when viscous lava is forced upward causing the surface to bulge. The 1980 eruption of Mount St. Helens was an example; lava beneath the surface of the mountain created an upward bulge, which later collapsed down

7345-429: The casing surrounding the explosive, and/or any other loose miscellaneous items not vaporized by the shock wave from the explosion. High velocity, low angle fragments can travel hundreds of metres with enough energy to initiate other surrounding high explosive items, injure or kill personnel, and/or damage vehicles or structures. Classical Latin explōdō means "to hiss a bad actor off the stage", "to drive an actor off

7458-580: The circulating refrigerant in suitably constructed compressor-based refrigeration. Compared to fluorocarbons, propane has a negligible ozone depletion potential and very low global warming potential (having a GWP value of 0.072, 13.9 times lower than the GWP of carbon dioxide) and can serve as a functional replacement for R-12 , R-22 , R-134a , and other chlorofluorocarbon or hydrofluorocarbon refrigerants in conventional stationary refrigeration and air conditioning systems. Because its global warming effect

7571-414: The coal cannot be used as an explosive (except in the form of coal dust ) because the rate at which it yields this heat is quite slow. In fact, a substance that burns less rapidly ( i.e. slow combustion ) may actually evolve more total heat than an explosive that detonates rapidly ( i.e. fast combustion ). In the former, slow combustion converts more of the internal energy ( i.e. chemical potential ) of

7684-619: The dominant source of benzene produced by cooking. In rural areas of North America, as well as northern Australia, propane is used to heat livestock facilities, in grain dryers, and other heat-producing appliances. When used for heating or grain drying it is usually stored in a large, permanently-placed cylinder which is refilled by a propane-delivery truck. As of 2014 , 6.2 million American households use propane as their primary heating fuel. In North America, local delivery trucks with an average cylinder size of 3,000 US gallons (11 m ), fill up large cylinders that are permanently installed on

7797-799: The enormous area they cover, and subsequent concealment under vegetation and glacial deposits, supervolcanoes can be difficult to identify in the geologic record without careful geologic mapping . Known examples include Yellowstone Caldera in Yellowstone National Park and Valles Caldera in New Mexico (both western United States); Lake Taupō in New Zealand; Lake Toba in Sumatra , Indonesia; and Ngorongoro Crater in Tanzania. Volcanoes that, though large, are not large enough to be called supervolcanoes, may also form calderas in

7910-428: The explosion resulting from the released (initially liquid and then almost instantaneously gaseous) propane in the presence of an ignition source. For this reason, emergency workers often differentiate between the two events. In addition to stellar nuclear explosions , a nuclear weapon is a type of explosive weapon that derives its destructive force from nuclear fission or from a combination of fission and fusion. As

8023-577: The floor to the pilot light on the furnace or water heater, and results in an explosion or fire. This property makes propane generally unsuitable as a fuel for boats. In 2007, a heavily investigated vapor-related explosion occurred in Ghent, West Virginia, U.S., killing four people and completely destroying the Little General convenience store on Flat Top Road , causing several injuries. Another hazard associated with propane storage and transport

8136-431: The flow is covered with angular, vesicle-poor blocks. Rhyolitic flows typically consist largely of obsidian . Tephra is made when magma inside the volcano is blown apart by the rapid expansion of hot volcanic gases. Magma commonly explodes as the gas dissolved in it comes out of solution as the pressure decreases when it flows to the surface . These violent explosions produce particles of material that can then fly from

8249-610: The formation of a submarine volcano off the coast of Mayotte . Subglacial volcanoes develop underneath ice caps . They are made up of lava plateaus capping extensive pillow lavas and palagonite . These volcanoes are also called table mountains, tuyas , or (in Iceland) mobergs. Very good examples of this type of volcano can be seen in Iceland and in British Columbia . The origin of the term comes from Tuya Butte , which

8362-408: The freezing point of water. The cold gas, which appears white due to moisture condensing from the air, may cause frostbite. Propane is denser than air. If a leak in a propane fuel system occurs, the vaporized gas will have a tendency to sink into any enclosed area and thus poses a risk of explosion and fire. The typical scenario is a leaking cylinder stored in a basement; the propane leak drifts across

8475-585: The future. In an article justifying the re-classification of Alaska's Mount Edgecumbe volcano from "dormant" to "active", volcanologists at the Alaska Volcano Observatory pointed out that the term "dormant" in reference to volcanoes has been deprecated over the past few decades and that "[t]he term "dormant volcano" is so little used and undefined in modern volcanology that the Encyclopedia of Volcanoes (2000) does not contain it in

8588-461: The gas to bubble out of solution, resulting in a rapid increase in volume, however the size of the magma chamber remains the same. This results in pressure buildup that eventually leads to an explosive eruption. Explosions can also occur outside of Earth in the universe in events such as supernovae , or, more commonly, stellar flares. Humans are also able to create explosions through the use of explosives , or through nuclear fission or fusion , as in

8701-466: The glossaries or index", however the USGS still widely employs the term. Previously a volcano was often considered to be extinct if there were no written records of its activity. Such a generalization is inconsistent with observation and deeper study, as has occurred recently with the unexpected eruption of the Chaitén volcano in 2008. Modern volcanic activity monitoring techniques, and improvements in

8814-492: The interior of a continent and lead to rifting. Early stages of rifting are characterized by flood basalts and may progress to the point where a tectonic plate is completely split. A divergent plate boundary then develops between the two halves of the split plate. However, rifting often fails to completely split the continental lithosphere (such as in an aulacogen ), and failed rifts are characterized by volcanoes that erupt unusual alkali lava or carbonatites . Examples include

8927-419: The mid-oceanic ridge is above sea level, volcanic islands are formed, such as Iceland . Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. The oceanic plate subducts (dives beneath the continental plate), forming a deep ocean trench just offshore. In a process called flux melting , water released from the subducting plate lowers the melting temperature of

9040-551: The modelling of the factors that produce eruptions, have helped the understanding of why volcanoes may remain dormant for a long time, and then become unexpectedly active again. The potential for eruptions, and their style, depend mainly upon the state of the magma storage system under the volcano, the eruption trigger mechanism and its timescale. For example, the Yellowstone volcano has a repose/recharge period of around 700,000 years, and Toba of around 380,000 years. Vesuvius

9153-415: The most dangerous type, are very rare; four are known from the last million years , and about 60 historical VEI 8 eruptions have been identified in the geologic record over millions of years. A supervolcano can produce devastation on a continental scale, and severely cool global temperatures for many years after the eruption due to the huge volumes of sulfur and ash released into the atmosphere. Because of

9266-438: The mud volcano is actually a vent of an igneous volcano. Volcanic fissure vents are flat, linear fractures through which lava emerges. Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lava that can flow a great distance from a vent. They generally do not explode catastrophically but are characterized by relatively gentle effusive eruptions . Since low-viscosity magma

9379-452: The next. Water vapour is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide . Other principal volcanic gases include hydrogen sulfide , hydrogen chloride , and hydrogen fluoride . A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen , carbon monoxide , halocarbons , organic compounds, and volatile metal chlorides. The form and style of an eruption of

9492-876: The north side of the mountain. Cinder cones result from eruptions of mostly small pieces of scoria and pyroclastics (both resemble cinders, hence the name of this volcano type) that build up around the vent. These can be relatively short-lived eruptions that produce a cone-shaped hill perhaps 30 to 400 metres (100 to 1,300 ft) high. Most cinder cones erupt only once and some may be found in monogenetic volcanic fields that may include other features that form when magma comes into contact with water such as maar explosion craters and tuff rings . Cinder cones may form as flank vents on larger volcanoes, or occur on their own. Parícutin in Mexico and Sunset Crater in Arizona are examples of cinder cones. In New Mexico , Caja del Rio

9605-549: The ocean surface as new islands or floating pumice rafts . In May and June 2018, a multitude of seismic signals were detected by earthquake monitoring agencies all over the world. They took the form of unusual humming sounds, and some of the signals detected in November of that year had a duration of up to 20 minutes. An oceanographic research campaign in May 2019 showed that the previously mysterious humming noises were caused by

9718-420: The ocean surface, due to the rapid cooling effect and increased buoyancy in water (as compared to air), which often causes volcanic vents to form steep pillars on the ocean floor. Hydrothermal vents are common near these volcanoes, and some support peculiar ecosystems based on chemotrophs feeding on dissolved minerals. Over time, the formations created by submarine volcanoes may become so large that they break

9831-471: The ocean's surface. In the deep ocean basins, the tremendous weight of the water prevents the explosive release of steam and gases; however, submarine eruptions can be detected by hydrophones and by the discoloration of water because of volcanic gases . Pillow lava is a common eruptive product of submarine volcanoes and is characterized by thick sequences of discontinuous pillow-shaped masses which form underwater. Even large submarine eruptions may not disturb

9944-468: The one that destroyed the city of Saint-Pierre in Martinique in 1902. They are also steeper than shield volcanoes, with slopes of 30–35° compared to slopes of generally 5–10°, and their loose tephra are material for dangerous lahars . Large pieces of tephra are called volcanic bombs . Big bombs can measure more than 1.2 metres (4 ft) across and weigh several tons. A supervolcano is defined as

10057-425: The overlying mantle wedge, thus creating magma . This magma tends to be extremely viscous because of its high silica content, so it often does not reach the surface but cools and solidifies at depth . When it does reach the surface, however, a volcano is formed. Thus subduction zones are bordered by chains of volcanoes called volcanic arcs . Typical examples are the volcanoes in the Pacific Ring of Fire , such as

10170-619: The plume, and new volcanoes are created where the plate advances over the plume. The Hawaiian Islands are thought to have been formed in such a manner, as has the Snake River Plain , with the Yellowstone Caldera being part of the North American plate currently above the Yellowstone hotspot . However, the mantle plume hypothesis has been questioned. Sustained upwelling of hot mantle rock can develop under

10283-419: The presence of oxygen. Accidental explosions may occur in fuel tanks, rocket engines, etc. A high current electrical fault can create an "electrical explosion" by forming a high-energy electrical arc which rapidly vaporizes metal and insulation material. This arc flash hazard is a danger to people working on energized switchgear . Excessive magnetic pressure within an ultra-strong electromagnet can cause

10396-511: The propane consumed each year, with about 70% of that coming from Canada via pipeline and rail. The remaining 30% of imported propane comes to the United States from other sources via ocean transport. After it is separated from the crude oil, North American propane is stored in huge salt caverns . Examples of these are Fort Saskatchewan , Alberta ; Mont Belvieu, Texas ; and Conway, Kansas . These salt caverns can store 80,000,000 barrels (13,000,000 m ) of propane. As of October 2013 ,

10509-457: The property, or other service trucks exchange empty cylinders of propane with filled cylinders. Large tractor-trailer trucks, with an average cylinder size of 10,000 US gallons (38 m ), transport propane from the pipeline or refinery to the local bulk plant. The bobtail tank truck is not unique to the North American market, though the practice is not as common elsewhere, and the vehicles are generally called tankers . In many countries, propane

10622-425: The raw gas, to prevent condensation of these volatiles in natural gas pipelines. Additionally, oil refineries produce some propane as a by-product of cracking petroleum into gasoline or heating oil. The supply of propane cannot easily be adjusted to meet increased demand, because of the by-product nature of propane production. About 90% of U.S. propane is domestically produced. The United States imports about 10% of

10735-437: The retail cost of propane was approximately $ 2.37 per gallon, or roughly $ 25.95 per 1 million BTUs. This means that filling a 500-gallon propane tank, which is what households that use propane as their main source of energy usually require, cost $ 948 (80% of 500 gallons or 400 gallons), a 7.5% increase on the 2012–2013 winter season average US price. However, propane costs per gallon change significantly from one state to another:

10848-435: The same time interval. Volcanoes vary greatly in their level of activity, with individual volcanic systems having an eruption recurrence ranging from several times a year to once in tens of thousands of years. Volcanoes are informally described as erupting , active , dormant , or extinct , but the definitions of these terms are not entirely uniform among volcanologists. The level of activity of most volcanoes falls upon

10961-492: The same way; they are often described as "caldera volcanoes". Submarine volcanoes are common features of the ocean floor. Volcanic activity during the Holocene Epoch has been documented at only 119 submarine volcanoes, but there may be more than one million geologically young submarine volcanoes on the ocean floor. In shallow water, active volcanoes disclose their presence by blasting steam and rocky debris high above

11074-622: The solidified erupted material that makes up the mantle of a volcano may be stripped away that its inner anatomy becomes apparent. Using the metaphor of biological anatomy , such a process is called "dissection". Cinder Hill , a feature of Mount Bird on Ross Island , Antarctica , is a prominent example of a dissected volcano. Volcanoes that were, on a geological timescale, recently active, such as for example Mount Kaimon in southern Kyūshū , Japan , tend to be undissected. Eruption styles are broadly divided into magmatic, phreatomagmatic, and phreatic eruptions. The intensity of explosive volcanism

11187-619: The stage by making noise", from ex- ("out") + plaudō ("to clap; to applaud"). The modern meaning developed later: In English: Volcano A volcano is a rupture in the crust of a planetary-mass object , such as Earth , that allows hot lava , volcanic ash , and gases to escape from a magma chamber below the surface. The process that forms volcanoes is called volcanism . On Earth, volcanoes are most often found where tectonic plates are diverging or converging , and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example,

11300-406: The surrounding areas, and initially not seismically monitored before its unanticipated and catastrophic eruption of 1991. Two other examples of volcanoes that were once thought to be extinct, before springing back into eruptive activity were the long-dormant Soufrière Hills volcano on the island of Montserrat , thought to be extinct until activity resumed in 1995 (turning its capital Plymouth into

11413-459: The tangling of magnetic field lines resulting from the rotation of the Sun's conductive plasma. Another type of large astronomical explosion occurs when a meteoroid or an asteroid impacts the surface of another object, or explodes in its atmosphere , such as a planet. This occurs because the two objects are moving at very high speed relative to each other (a minimum of 11.2 kilometres per second (7.0 mi/s) for an Earth impacting body). For example,

11526-434: The theory of plate tectonics. For example, some volcanoes are polygenetic with more than one period of activity during their history; other volcanoes that become extinct after erupting exactly once are monogenetic (meaning "one life") and such volcanoes are often grouped together in a geographical region. At the mid-ocean ridges , two tectonic plates diverge from one another as hot mantle rock creeps upwards beneath

11639-444: The thinned oceanic crust . The decrease of pressure in the rising mantle rock leads to adiabatic expansion and the partial melting of the rock, causing volcanism and creating new oceanic crust. Most divergent plate boundaries are at the bottom of the oceans, and so most volcanic activity on Earth is submarine, forming new seafloor . Black smokers (also known as deep sea vents) are evidence of this kind of volcanic activity. Where

11752-431: The underlying ductile mantle , and most volcanic activity on Earth takes place along plate boundaries, where plates are converging (and lithosphere is being destroyed) or are diverging (and new lithosphere is being created). During the development of geological theory, certain concepts that allowed the grouping of volcanoes in time, place, structure and composition have developed that ultimately have had to be explained in

11865-492: The volcano. Solid particles smaller than 2 mm in diameter ( sand-sized or smaller) are called volcanic ash. Tephra and other volcaniclastics (shattered volcanic material) make up more of the volume of many volcanoes than do lava flows. Volcaniclastics may have contributed as much as a third of all sedimentation in the geologic record. The production of large volumes of tephra is characteristic of explosive volcanism. Through natural processes, mainly erosion , so much of

11978-424: The volcanoes of the East African Rift . A volcano needs a reservoir of molten magma (e.g. a magma chamber), a conduit to allow magma to rise through the crust, and a vent to allow the magma to escape above the surface as lava. The erupted volcanic material (lava and tephra) that is deposited around the vent is known as a volcanic edifice , typically a volcanic cone or mountain. The most common perception of

12091-547: The world, propane used in vehicles is known as autogas. In 2007, approximately 13 million vehicles worldwide use autogas. The advantage of propane in cars is its liquid state at a moderate pressure. This allows fast refill times, affordable fuel cylinder construction, and price ranges typically just over half that of gasoline. Meanwhile, it is noticeably cleaner (both in handling, and in combustion), results in less engine wear (due to carbon deposits) without diluting engine oil (often extending oil-change intervals), and until recently

12204-547: Was derived from " propionic acid ", which in turn was named after the Greek words protos (meaning first) and pion (fat), as it was the "first" member of the series of fatty acids . Propane is a colorless, odorless gas. Ethyl mercaptan is added as a safety precaution as an odorant , and is commonly called a "rotten egg" smell. At normal pressure it liquifies below its boiling point at −42 °C and solidifies below its melting point at −187.7 °C. Propane crystallizes in

12317-421: Was described by Roman writers as having been covered with gardens and vineyards before its unexpected eruption of 79 CE , which destroyed the towns of Herculaneum and Pompeii . Accordingly, it can sometimes be difficult to distinguish between an extinct volcano and a dormant (inactive) one. Long volcano dormancy is known to decrease awareness. Pinatubo was an inconspicuous volcano, unknown to most people in

12430-443: Was developed by Frank Peterson and its patent was granted on July 2, 1912. The 1920s saw increased production of LP gases, with the first year of recorded production totaling 223,000 US gallons (840 m ) in 1922. In 1927, annual marketed LP gas production reached 1 million US gallons (3,800 m ), and by 1935, the annual sales of LP gas had reached 56 million US gallons (210,000 m ). Major industry developments in

12543-532: Was during this time that Snelling — in cooperation with Frank P. Peterson, Chester Kerr, and Arthur Kerr — developed ways to liquefy the LP gases during the refining of gasoline. Together, they established American Gasol Co., the first commercial marketer of propane. Snelling had produced relatively pure propane by 1911, and on March 25, 1913, his method of processing and producing LP gases was issued patent #1,056,845. A separate method of producing LP gas through compression

12656-663: Was found dissolved in Pennsylvanian light crude oil by Edmund Ronalds in 1864. Walter O. Snelling of the U.S. Bureau of Mines highlighted it as a volatile component in gasoline in 1910, which marked the "birth of the propane industry" in the United States. The volatility of these lighter hydrocarbons caused them to be known as "wild" because of the high vapor pressures of unrefined gasoline. On March 31, 1912, The New York Times reported on Snelling's work with liquefied gas, saying "a steel bottle will carry enough gas to light an ordinary home for three weeks". It

12769-467: Was relatively low-cost in North America. The octane rating of propane is relatively high at 110. In the United States the propane fueling infrastructure is the most developed of all alternative vehicle fuels. Many converted vehicles have provisions for topping off from "barbecue bottles". Purpose-built vehicles are often in commercially owned fleets, and have private fueling facilities. A further saving for propane fuel vehicle operators, especially in fleets,

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