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.
A2Z Languages 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.
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