Costa
Rica lies at the heart of one of the most active volcanic regions
on earth. The beauty of the Costa Rican landscape has been enhanced
by volcanic cones--part of the Pacific Rim of Fire--that march
the length of Central America. Costa Rica has seven of the isthmus's
42 active volcanoes, plus 60 dormant or extinct volcanoes. Some
have the look classically associated with volcanoes--a graceful
symmetrical cone rising to a single crater. Others are sprawling,
much-weathered mountains whose once-noble summits collapsed
into huge depressions, called calderas. Still others have smooth
shield-shaped outlines with rounded tops pockmarked by tiny
craters, such as on Cocos Island.
Poás
Visitors seeking to peer
into the bowels of a rumbling volcano can easily do so. The
reward is a scene of awful grandeur, like the fires of Milton's
hell. Atop Poás's crater rim, for example, you can gape
down into the great well-like vent where pools of molten lava
bubble menacingly--with diabolical, gut-wrenching fumes of chlorine
and sulfur, and explosive cracks, like the sound of distant
artillery, for good effect.
Several national parks have
been created around active volcanoes, with accommodations, viewing
facilities, and lectures and guided walks to assist visitors
in understanding the processes at work. A descriptive map charting
the volcanoes is published by the Vulcanological and Seismological
Observatory of Costa Rica at the National University in Heredia,
which monitors volcanic activity throughout the nation (Libreria
Lehmann and Libreria Trejos, in San José, may sell the
map).
Irazú
In
1963, Irazú (elev. 3,412 meters) broke a 20-year silence
to begin disgorging great clouds of smoke and ash. The eruptions
triggered a bizarre storm which showered San José in
five inches of muddy ash and snuffed out the 1964 coffee crop,
enriching the Meseta Central for years to come. The binge lasted
for two years, then abruptly ceased. Poás (elev. 2,692
meters) has been particularly virulent during the past 30 years.
In the 1950s, the restless four-mile-wide giant awoke with a
roar after a 60-year snooze, and it has been huffing and puffing
ever since. Eruptions then kicked up a new cone several hundred
feet high. Two of Poás's craters now slumber under blankets
of vegetation (one even cradles a lake), but the third crater
belches and bubbles persistently. In 1989, a spate of intense
eruptions and gas emissions forced Poás Volcano National
Park to close (local residents were even evacuated), and the
volcano is constantly monitored for impending eruptions.
Arenal
A more spectacular light-and-sound
show is given by Arenal (elev. 1,624 meters). Following a four-century-long
Rip van Winkle-like dormancy, this 4,000-year-young juvenile
began spouting in 1968, when it laid a four-square-mile area
to waste. Arenal's activity, sometimes minor and sometimes not,
continues unabated. Though currently more placid, Miravalles,
Turrialba, and Rincón de la Vieja, among Costa Rica's
coterie of coquettish volcanoes, also occasionally fling fiery
fountains of lava and breccia into the air.
The type of magma that fuels
most Central American volcanoes is thick, viscous, and so filled
with gases that the erupting magma often blasts violently into
the air. If it erupts in great quantity, it may leave a void
within the volcano's interior, into which the top of the mountain
crumbles to form a caldera (from the Portuguese word for caldron).
Irazú is a classic example. Irazú's top fell in
eons ago. Since then, however, small eruptions have built up
three new volcanic cones--"like a set of nesting cups,"
says one writer--within the ancient caldera.
Much
of the information on our site as it relates to Costa Rica is:
Courtesy
of Christopher P. Baker and Avalon Travel Publishing.
© 2004 Christopher P. Baker. All Rights Reserved.
Spanish Abroad, Inc. highly
recommends Christopher P. Baker's book: Moon
Handbooks Costa Rica. Click on the image to
visit his website where you can purchase this book or find out
more about the author.
