The Amazing Volcano

By “Awake!” correspondent in Guatemala

FOR centuries volcanoes have both fascinated and terrified people. In ancient times some persons went so far as to worship volcanoes. The word itself comes from Volcanus, the Latin name of the Roman god of fire.

Noting that a volcano is “an opening in the earth’s surface,” The World Book Encyclopedia explains: “Through this opening has come rock so hot that it is in a liquid or gaseous state. This melted rock deep in the earth is called magma.” It is thought that chambers of extremely hot magma are located twenty to forty miles below Earth’s surface. When magma presses against the roof of a chamber, gases are released. Upon reaching weak spots in the crust of the globe, these gases hollow out a passage, or “conduit,” that eventually reaches the surface.

When it gets to the surface of the earth, magma cools into “lava.” This escapes through an opening in the crust, spilling out over the edges of the volcano’s crater. “From time to time,” notes the reference work quoted above, “the opening becomes choked by cooling magma. This again causes gases to build up pressure to blast the plugging material into the air.”

Guatemala is known for its volcanoes; there are more than thirty-three of them in that country of Central America. A person traveling south from Mexico toward Guatemala City can see one volcanic peak after another, which appear as a formidable mountain range. However, most of Guatemala’s volcanoes now are inactive.

Among the active ones is Santiaguito. This volcano was born at the end of the 1800’s, pushing itself out of the side of a larger parent volcano. An elderly woman, who, as a little girl, witnessed the birth of Santiaguito, recalls that ‘it first spewed pumice and fine sand like ash that covered everything nearby to a depth of several feet.’ It is still necessary to dig holes several feet through pumice and sand to reach the former topsoil for planting coffee trees in the vicinity of Santiaguito.

Another of Guatemala’s active volcanoes is Pacaya, which has been erupting on and off for several years. An eyewitness of Pacaya “doing its thing,” as he put it, reports: ‘It looks as if fire is shooting out of the top. Several fiery streams that flow down the mountain look like fingers dipped in phosphorescent paint glowing in the dark.’

Guatemala’s most violent volcano is Fuego, which in Spanish means “fire.” On October 13, 1974, dwellers in Guatemala City stood in open areas and on rooftops to watch Fuego erupt, a truly fear-inspiring spectacle. They witnessed the appearance of flames shooting thousands of feet into the air. They also saw lightning strike at the volcano from cloudless skies, a phenomenon that for centuries has been known to accompany volcanic eruptions. The huge volume of sand belched out by Fuego covered and partially ruined cotton plantations and fields of sesame plants.

Did you know that, for the most part, the “flames” that leap heavenward when a volcano erupts are not ordinary fire? Flames usually result from burning of combustible materials, during which substances are released that react with oxygen in the air. However, most “flames” from volcanoes do not come from combustion. Instead, they are jets of glowing particles formed from the molten lava. When the lava escapes its high-pressure environment deep in the volcano and enters ordinary atmospheric pressure, exploding gases propel these particles sky-high, giving the appearance of shooting flames. The particles then cool off and solidify to form dense clouds of pumice, which settles over the countryside, ruining crops.

Volcanic gases consist mostly of steam. Carbon dioxide and nitrogen are sometimes major components. In smaller quantities these gases may include hydrochloric acid, hydrofluoric acid, sulfur, hydrogen sulfide, sulfur dioxide, hydrogen, and carbon monoxide. Interestingly, of these, only sulfur, hydrogen and carbon monoxide are combustible. These minor contributors, therefore, are responsible for the only true flames in volcanic eruptions.

Many may be inclined to regard volcanoes with fear, for on occasion they have caused large-scale loss of life and property. But volcanoes also have served for man’s benefit. Volcanic steam has been tapped to produce heat and electric power. Hot springs serve medicinal, laundry and bathing purposes. Lava can be used as a building material. Pumice is a popular grinding and polishing agent. And lava beds, since these are porous and allow fresh water to collect, are important sources of water. Many, indeed, are the benefits to man from the amazing volcano.