Tuesday, June 28, 2011

Mexico’s Volcanoes

Mt. Paricutín quiet and on fire!

Mexico is home to some of the world’s greatest volcanoes, and to some of the most active. Volcanoes were held sacred by the peoples of ancient Mexico. Now, as then, volcanoes are viewed with awe, respect, and often fear by people living in their shadows. The country’s highest peak is the mighty Mt. Orizaba. This snow-capped, 18,406-foot (5,610-meter) volcanic giant is the third highest mountain in North America. Most volcanic activity occurs in an area reaching from Mexico City southward. This huge capital city, in fact, is surrounded on three sides by a high wall of volcanoes—including Iztaccíhuatl and Popocatépetl, both of which rise to over 17,000 feet (5,182 meters). Several of Mexico’s volcanoes have been active in recent years. Unfortunately, they are located in densely populated areas, and they pose a great threat to human life and property.

Certainly one of Mexico’s, if not the world’s, most famous volcanic peaks is Mt. Paricutín. One morning in 1943, a farmer named Dionisio Pulido was plowing his field near San Juan, a small town located some 180 miles (290 kilometers) west of Mexico City. Plodding along behind his yoke (team) of oxen, he suddenly noticed a strange odor. Imagine his shock when he saw a thin column of smoke spiraling upward from a small hole in his field! Not knowing what to do, he covered the hole with a rock and continued plowing.

Soon, he noticed even more smoke coming from the ground. Startled by this strange sight, he ran to the village to tell the priest and townspeople what was happening in his field. Many people returned to the field with him to see this strange event for themselves. When they arrived, a hole nearly 30 feet (9 meters) deep had formed. This gaping monster was now belching dense black clouds of foul-smelling smoke.

That night, a violent explosion shook the village, and a mountain began to rise from the field that Señor Pulido had been plowing only hours earlier. Within one week, the mountain had reached a height of 560 feet (171 meters). Two months later, it had grown to nearly 1,000 feet (305 meters) and was still growing. Today, a 1,300-foot (396-meter) high volcanic cinder cone—Mt. Pericutín—rises above the field in which corn once grew.

El Chicón is a large volcanic peak located in Chiapas State just east of the Isthmus of Tehuantepec. In 1982 the mountain erupted violently, spewing huge clouds of ash high into the atmosphere. Scientists believe that the volcanic ash shaded Earth from some of the sun’s rays, causing temperatures worldwide to be 2° to 3°F (.5 to 1.5°C) cooler for several years. “El Popo,” as Mexicans call the giant Mt. Popocatépetl, rises to an elevation of 17,887 feet (5,452 meters). It is one of the tallest active volcanoes in the world. Unfortunately, it is also located in one of the world’s most densely populated areas. More than 25 million people, including most residents of Mexico City, live within 40 miles (64 kilometers) of the volcanic peak. Recently, El Popo has shown increasing activity. During the late 1990s, the volcano once again began living up to its Aztec name—“Smoking Mountain.” It experienced several rather violent eruptions, sending huge clouds of smoke and ash thousands of feet into the atmosphere.

There is reason to fear Popocatépetl. Three things could happen that would devastate vast areas, two of which could take a terrible toll of human lives. First, an eruption of gas, dust, and ash (such as that of the late 1990s) could change Earth’s temperature for several years and also bury surrounding areas in gritty ash. A second type of event, a blast of hot lava and ash, would melt glaciers and snow on the mountain’s northern slope. This would cause lahars, or mudflows, that would race down the mountain and into the surrounding valley, destroying everything in their path. Finally, some scientists fear a more violent eruption, similar to the 1981 massive blast of Mount Saint Helens in Washington State. In such a densely populated area, were this kind of violent eruption to occur, millions of people could be killed and billions of dollars of property destroyed.

Much of western and southern Mexico also lies on fault zones that spawn severe earthquakes. Nearly all places located on the half of Mexico facing the Pacific Ocean have experienced destructive tremors. Many communities have been struck on numerous occasions. In 1985 a violent earthquake struck the heart of Mexico City. More than 10,000 people were killed, hundreds of thousands of families were left homeless, and the devastation caused billions of dollars in property losses.

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