To know how Costa Ria’s volcanoes forms and exists, requires a basic understanding Costa Rica’s volcano types, sections, plug, crater, sites and creation.
Worldwide there are three (3) types of Volcanoes:
LINKS TO THE THREE PICTURES BELOW
1) Composite Volcanoes
2) Cinder Cone Volcanoes
3) Shield Volcanoes
Stratovolcano or Composite Volcanos
Cinder Cone Volcanos
Shield Volcanos
Costa Rica’s volcanoes are of the, stratovolcano or composite type. Their conical shape has been formed over millions of years; additional layers of hardened lava, pumice, tephra, ash, and rock, each layer building on-top-of the previous layer until the volcanoes ascend to their current heights.
Costa Rica Volcanoes Consist of Five Sections
Looking at a volcano from the top (Crater) down, its sections are-
1) The Crater is located at the top of the volcano; usually bowl shaped, made by a volcanic eruption after which a volcanic plug capped the conduit.
2) A Conduit is the tube carrying hot magma from via fissures from the magma chamber. Occasionally a plug in the vent my resist the pressure coming through the conduit sufficient for the magma to forge an alternate path which will blow out of the volcanoes slope somewhere other than its crater.
3) The Magma Chamber is an underground pool of boiling rock (Magma) linked to the vent by a conduit.
4) Vents are points at which the conduit opens into the atmosphere.
5) Slopes are the external walls (sides) of the volcano.
Another important volcanic formation is a ‘Volcanic Plug’. When magma cools it first becomes larva and then larva cools and solidifies forming a ‘volcanic plug’ sealing the conduit near or at the vent. The plug forces pressure to build behind it in conduit.
Volcanic Plug-Another Formation
Another special volcanic formation is a ‘Volcanic Plug’. When magma cools it first becomes larva and then larva cools and solidifies forming a ‘volcanic plug’ sealing the conduit near the vent. The plug forces pressure to build wherever it blocks the conduit. In some other places in the world the Volcanic Plug has been exposed by time and erosion; some examples are- Morro Rock in California, Thumb Butte in the Sierra Prieta of Arizona, and Shiprock in New Mexico.
Above the Volcano’s Crater
The clouds floating around the top of the crater are a combination of gasses (usually toxic), made of fine pyroclasts or other volcanic fragments, salts, smoke, and acids all suspended in the air by moisture in the thermal updrafts.
The warm air in the thermals mixes with cooler ocean breezes and produce lots of condensation (rain). The rainforest cloaking most of Costa Rica is regularly watered by this rain and then distributed throughout the country by many colorful rivers.
Volcanic Sites in Costa Rica
Amazingly, there are over 200 identifiable volcanic sites in Costa Rica. Of that number, only six (6) are active and sixty-one (61) are inactive; some of the others may be considered extinct*.
Of Costa Rica’s six active volcanoes five of them are over 6,000 feet high.
Volcanic States
Volcanoes exist in one of these three (3) states-
1) Active
2020 Phreatic Eruption at Rincon de la Vieja
2) Dormant
Dormant Chato Volcano
3) Inactive
Inactive Orosi Volcano
*NB-For a volcano to be classified as extinct, they must remain inactive for at least 10,000 years.
Costa Rica Volcanic Range (Cordillera de Guanacaste)
Formed by two significant mountain ranges about 68 miles long (110 km) in the North Eastern corner the ‘Cordillera de Guanacaste’ stands near the Nicaraguan border.
The Cordillera de Guanacaste is a series of Complex or Stratovolcanoes.
1) La Cordillera– runs from the Osi Volcano to the Arenal Volcano.
2) La Sierra Minera– is located between Arenal Volcano and Tapezco Pass.
The highest peak on the Cordillera is Miravalles Volcano at 6,654’ (2,028 m). It was declared a U.N.E.S.C.O. heritage site in 1999. The geothermal heat produced by this volcano generates electrical power at the geothermal energy plant at Las Hornillias.
Each Costa Rican Volcano has a National Park surrounding it. They continually monitor the volcanoes’ attitude ensuring that even the slightest changes are detected and recorded. When activity increases inside a volcano it immediately sends signals triggering alarms locally and internationally.
Volcano Creation
Volcanoes are the end result of a process that has taken billions of years; they were defined on a planets crust (several astronomical planets have volcanoes); here on earth they develop in an area where hot magma from the earth’s core bubbled close to the crust. Cool magma and it becomes larva, then travelling through fissures and gaps in the tectonic plates towards the surface (crust) it creates an abscess on the crust that will grow from the ground into a 6,000 foot volcano.
Learning to identify types, sections, plug, crater, sites and the creation of Costa Rica’s volcanoes, a better appreciation for their magnificence is enriched.
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