Volcano

An active volcano emits gases, hquids, and sohds. The gases spewed into the atmosphere include primarily N2, CO2, HCl, HF, H2S, and water vapor. It is estimated that volcanoes are the source of about two-thirds of the sulfur in the air. On the slopes of Mount St. Helens, which last erupted in 1980, deposits of elemental sttUrtr are visible near the eruption site. At high tempera-tmes, the hydrogen sulfide gas given off by a volcano is oxidized by air  

Some of the SO2 is reduced by more H2S from the volcano to elemental sulfur and water  

The rest of the SO2 is released into the atmosphere, where it reacts with water to form add rain (see Section 21.6). 

The tremendous force of a volcanic eraption carries a sizable amoimt of gas into the stratosphere. There SO2 is oxidized to SO3, which is eventually converted to sulfuric acid aerosols in a series of complex reactions. In addition to destroying ozone in the stratosphere (see page 901), these aerosols can also affect climate. Because the stratosphere is above the atmospheric weather patterns, the aerosol clouds often persist for more than a year. They absorb solar radiation and thereby cause a drop in temperature at Earth s surface. However, this cooling effect is local rather than global, because it depends on the site and frequency of volcanic eraptions. 

Geophysical data indicate that the average thickness of the continental crust of East Antarctica is about 40 km. However, the crust thickens appreciably to about 55 km under the Transantarctic Mountains and under the subglacial Gamburtsev Mountains located in East Antarctica between 70° and 80°E longimde at about 80°S latitude (Bentley 1983 Kadmina et al. 1983). 

The present elevation of the bedrock surface of some parts of East and West Antarctica is actually below sea level. Eor example, two large subglacial basins in Wilkes Land of East Antarctica lie below sea level. In addition, the surface of subglacial Lake Vostok at 78°28 S and 106°48 E is below sea level by about 200-300 m. The bedrock surface of most of West Antarctica is also below sea level partly because of the mass of the overlying ice sheet (Drewry et al. 1983 Bentley and Robertson 1982 Bentley et al. 1982). Consequently, the incursion of seawater into the subglacial basins could result in the hreak-np of the West Antarctic ice sheet and of the ice in the Wilkes basin of East Antarctica. 

Antarctica truly is the land of fire and ice because it contains a large number of volcanoes that were active during the Tertiary Period (LeMasurier 1990). At the present time only Mt. Erebus on Ross Island in Fig. 2.2a, b is still active. The summit of Mt. Erebus, 

Erebus was discovered in January of 1841 by Captain James Ross who named it after the ship he and his crew had sailed to Antarctica (Section 1.1). The volcano was emitting plumes of steam when it was discovered and it was still active in March of 1908 when it was climbed by William E. David and his five companions of Shackleton s Nimrod Expedition. When it was climbed a second time in Decanber of 1912 by Raymond Priestley and other members of Scott s Terra Nova Expedition, it was stiU active. The activity has continued into the modem era and actually intensified in 1982. The volcano became violent in December of 1984 when it ejected incandescent lava bombs accompanied by thunderous explosions and by the emission of colored steam and other gases. 

The volcanoes of Antarctica occur not only in the Transantarctic Mountains and on the islands off the coast of Victoria Land, but also in Marie Byrd Land of West Antarctica, on the Antarctic Peninsula and on its off-shore islands, on the South Sandwich Islands, in East Antarctica, and on the islands of the Southern Oceans. All of these volcanoes were described in a book edited by LeMasurier and Thomson (1990). The descriptions of the volcanoes include photographs, maps, chemical analyses of the rocks, and interpretations of these analyses. Even the Gaussberg on the coast of East Antarctica (Section 1.3.3) is included in this compilation of Antarctic volcanoes. The book also 

FIGURE 9.6 A volcano in a classic cone shape prodnced when molten lava and ash are ejeeted from a magma chamber undergronnd. 

Volcanic eruptions can cause some harmful health effects. Tourists were kept at some distance from the 2011 eruption of the Kilauea volcano (see Section 9.4.1) because of its emissions of sulfur dioxide gas. People may suffocate in the carbon dioxide or be poisoned by the toxic carbon monoxide and hydrogen sulfide. (If the geothermally active Yellowstone National Park in the United States was an industrial installation, it is likely that authorities would consider placing some areas off limits because of emissions of hydrogen sulfide, readily detected by visitors by its foul odor.) Fine particles blown into the atmosphere from volcanic eruptions can cause respiratory problems when inhaled. Plants may be killed or their growth stunted by exposure to sulfur dioxide and hydrogen sulfide from volcanoes. 

Massive, atmospheric-damaging eruptions of volcanoes in recorded history have caused catastrophic crop failures. These will happen again. And since the world as a whole carries little food surplus from year to year, the certainty of food supply disruptions due to volcanic activity points to the desirability of storing substantial amounts of food for emergency use. 

---

CH3 group ceases, and a multibeam H pattern is observed. Measuring tlie temperature dependence of tlie beam pattern broadening into tlie volcano pattern allows one to measure tlie energy required to make the -CH group... 

Sulfur occurs native in the vicinity of volcanos and hot springs. It is widely distributed in nature as iron pyrites, galena, sphalerite, cinnabar, stibnite, gypsum, epsom salts, celestite, barite, etc. 

Carbonyl sulfide is overall the most abundant sulfur-beating compound ia the earth s atmosphere 430—570 parts per trillion (10 ), although it is exceeded by H2S and SO2 ia some iadustrial urban atmospheres (27). Carbonyl sulfide is beheved to origiaate from microbes, volcanoes, and the burning of vegetation, as well as from iadustrial processes. It may be the main cause of atmospheric sulfur corrosion (28). 

Sulfur dioxide occurs in industrial and urban atmospheres at 1 ppb—1 ppm and in remote areas of the earth at 50—120 ppt (27). Plants and animals have a natural tolerance to low levels of sulfur dioxide. Natural sources include volcanoes and volcanic vents, decaying organic matter, and solar action on seawater (28,290,291). Sulfur dioxide is beHeved to be the main sulfur species produced by oxidation of dimethyl sulfide that is emitted from the ocean. 

In an oversimplified way, it may be stated that acids of the volcanoes have reacted with the bases of the rocks the compositions of the ocean (which is at the fkst end pokit (pH = 8) of the titration of a strong acid with a carbonate) and the atmosphere (which with its 2 = 10 atm atm is nearly ki equdibrium with the ocean) reflect the proton balance of reaction 1. Oxidation and reduction are accompanied by proton release and proton consumption, respectively. In order to maintain charge balance, the production of electrons, e, must eventually be balanced by the production of. The redox potential of the steady-state system is given by the partial pressure of oxygen (0.2 atm). Furthermore, the dissolution of rocks and the precipitation of minerals are accompanied by consumption and release, respectively. 

If the plates pull down, they would sink into the mantle and melt to form ocean basins. Some of the molten rock of these plates may travel to the earth s surface through the crevice so formed due to heat convection and cause a volcano. 

The places from which pollutants emanate are called sources. There are natural as well as anthropogenic sources of the permanent gases considered to be pollutants. These include plant and animal respiration and the decay of what was once living matter. Volcanoes and naturally caused forest fires are other natural sources. The places to which pollutants disappear from the air are called sinks. Sinks include the soil, vegetation, structures, and water bodies, particularly the oceans. The mechanisms whereby pollutants... 

An erupting volcano emits particulate matter. Pollutant gases such as SO2, HiS, and methane are also emitted. The emission from an eruption... 

The application of control technology to air pollution problems assumes that a source can be reduced to a predetermined level to meet a regulation or some unknown minimum value. Control technology carmot be applied to an uncontrollable source, such as a volcano, nor can it be expected to control a source completely to reduce emissions to zero. The cost of controlling any given air pollution source is usually an exponential function of the percentage of control and therefore becomes an important consideration in the level of control required (1). Figure 28-1 shows a typical cost curve for control equipment. 

Group 3 Nitrate/metal compositions without sulphur Compositions with <35-65% chlorate Compositions with black powder Lead oxide/silicon with >60% lead oxides Perchlorate/metal Burn fast Large firework shells Fuse protected signal flares Pressed report cartridges in primary packagings Quickmatches in transport packagings Waterfalls Silver wheels Volcanoes Black powder delays Burn very violently with single-item explosions... 

Studies of atmospheric particles show that their distribution is often birno-dal i.e., the particles are made up of rwo separate fractions, one with fine and one with coarse particles (Fig. 9.1). The coarse particles, from about 2.5 pm upward, are made up of natural dust from the effect of wind, erosion, plants, volcanoes, etc. The finer fraction is made up of particles smaller than 2.5 pm and consists primarily of particles from human activity, combustion, traffic, and processes. 

Wind-blown dust 1 missions Sea spray Volcanoes Plant particles... 

Vulkan, m. volcano Vulcan, -asbest, m. vulcanized asbestos, -fiber, /. Vulcanized Fiber. T.N. -gas, n. volcanic gas. -glas, n. volcanic glass tempered glass. 

Seismograph recording seismic actmty of Volcano Island, Philippines. (Corbis Corporation)... 

Some naturally occurring organohalogen compounds are produced in massive quantities. Forest fires, volcanoes, and marine kelp release up to 5 million tons of CH3CI per year, for example, while annual industrial emissions... 

VLDL, heart disease and, 1090-1091 Volcano, chloromethane from, 332 Vulcanization, 245-246, 499... 

The ammonium dichromate resembles a tiny volcano as it bums, emitting hot gases, sparks, and a voluminous green dust of chromium(III) oxide. 

And he and Ms. Stewart might share a Lover s Concerto, which is served in a volcano bowl with a shot of tequila. It would take the edge off. 

Electrochemical promotion of the unpromoted Rh/YSZ film, via application of 1 or -1 V, leads to significant rate enhancement (tenfold increase in rCo2> four fold increase in rN2 (filled circles and diamonds in Fig. 2.3). This is a catalytic system which as we will see in Chapters 4 and 8 exhibits inverted volcano behaviour, i.e. the catalytic rate is enhanced both with positive and with negative potential. 

Figure 4.15. Rate and catalyst potential response to application of negative currents (a,b), for the case of volcano-type behaviour, see text for discussion. Conditions pCo=2 kPa, p02=2 kPa, T=350°C. Catalyst Cl. 51 Reprinted with permission from Academic Press.

---