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In Costa Rica there are 112 volcanic formations. They belong to so called Pacific Rim of Fire. Seven of them is considered as active ones. Their activity is connected with fertile soils, which cover the majority of Costa Rica territory. Their suddenly erruptions made in past years huge destructions. The highest Costa Rica`s volcanoe is Irazu, the most active is Arenal and Poas has the second widest crater in the world. (diameter 1,5 kilometres).

In 1950`s terrains around each volcano were come to be preserved. Many of volcanos are now within the national parks. Costa Rica major volcanic peaks are stratovolcanoes. The type of magma that fuels most Costa Rica volcanoes is thick, viscous, and so filled with gases that the erupting magma often blasts violently into the air.

The most serious eruption was that of Irazu volcanoe in 1963. It erupted clouds of smoke and ash that kept shovering over San Jose and other parts for two years. People had been walking with handkerchief. From roofs on every day were being scraped layels of polders of even 13 centimetres thickness. Over 100 square kilometers of the surrounding land were devastated. The latest eruption in Costa Rica was of Arenal Volcanoe on August 24th, 2000. One person died and two were severly hurt. 600 residents have been evacuated.

Volcano Arenal

The most active Costa Rica volcano. It rises at 1633 m.a.s.l. at the edge of San Carlosb Lowland, on the eastern side of the like with the same name, in Alajuela province. It`s quite young volcano, about 3.000 years old. The volcano lovers declared it as the third volcano in the world with the most perfect conical shape. During XX century it was passing a few eruptive phases. The biggest eruption of the latest years took place on 29 July of 1968. The morning explosion destroyed everything within the 15 kilometres. The settlements like Pueblo Nuevo and Tabacon were rubbed from the map. More or less 80 people have lost their lifes. The following volcano eruptive activity recorded in 1975, when from the main crater the lava started to being appearing and flowing to Rio Tabacon. From June of 1984, Arenal come into new explosion phase. The ahes, muds and steam covered Arenal Lake and Tilaran town. Since that time on every day there are 3 - 20 explosions with lava flowing. It can be seen from the special view points. The volcano activity was recorded also in 1993 and 1996. The last one happened on August 24th, 2000. One person have been killed, 2 hurt and 600 evacuated. In 2001 the government established a buffer zone around the crater. The decree bans the construction of houses and tourist developments in a 5.5-kilometer.

Volcano Barva

(2.906 m.a.s.l.). The oldest Costa Rica volcano. It`s within the boundary of Braulio Carillo National Park. Since 1492 is considered to be dormant. Its calderic structure make the eastern wall of Meseta Central. Two main craters are filled by lakes with clear and cold water. (Barva Lake-700 m. of width and Danta Lake-500 m. of width). Its slopes are dotted with coffee seedlings and covered with cypress and pines tree forests. It`s the only place in the world where lives a toad Bufo Holdridge. (It`s inhabited also by Toad Harlequin).

Volcano Cacao

[1659 m.a.s.l.]. It`s placed in the Cordillera Guanacaste range. It has an open crater towards the south-west of which there is no recorded activity. On its steep slopes, numerous streams and rivers are born that flow into lake Nicaragua and the Nicoya Gulf as in the case of Tempsigue river. On its slope, at an elevation 1.050 m.a.s.l. there is a Cacao Biological Station.

Volcano Cacho Negro

Extinct volcanoe that is situated in Braulio Carillo National Park. It`s known for its perfect conical shape. Around that the cattle farms are situated. Its slopes are covered by cypress and pine forests.

Volcano Chato

(1.100 a.s.l.). Its name means "the flat hill". Its the volcanic formation with collapsed crater and idyllic lake inside that (it`s possible canoeing there). On August 2000 there was the plane crash, where 10 people have been killed. Another plane hit its slope on January 2001. One pilot died.

Volcano Congo

[2.014 m.n.p.m.]. Remants of twin volcano, the southern one. It come into existence about 1,5 milions years ago. From its slopes originates two small brookies that give water for laguna Hule. Since 1993 it is within the Poas Volcano National Park.

Volcano El Viejo

(2.122 m.n.p.m.) It`s situated to the north-west off Poas volcanoe. It can be reached through Bajos del Toro or Toro Amarillo in Palmira. It used to be called La Mina (a mine), because of the old private pumice-stone mine, that existed there. Its slopes are covered by cypresses and cedars. It belongs to the Juan Castro Blanco National Park.

Volcano Irazu

The highest volcanoe in the country towering at 3432 m.a.s.l. It`s the only place in America, from which it`s possible to see both oceans at once. On its slopes there are strawberries cultivations. There is a smell of sulphur on its top. Its main crater is round shaped and is filled with green water with sulphur and measures 1050 metres of wide and 300 metres of depth. The second crater Diego da la Haya (called that way in honour of spanish concvistador Fernandeza Diego de la Haya, who as the first recorded its eruption from XVIII century), has 600 metres of width and 100 metres of depth. The other craters are: Playa Hermosa, El Piroklastico and La Laguna. The name Irazu (Iztaru) derives from the language of Indians which used to live under its slopes. It means "a thunder" or "the place that shakes". Irazu had a few catastrophic eruptions. That one from 1723 destroyed completely off that time capital - Cartago. The eruption from 19 June 1963 covered San Jose with thick layer of ash. There was conviction that Irazu blows out on every 30 years. It`s called :"the deadly keg of powder".

Volcano Miravalles

[2.028 m.a.s.l.]. It`s situated 15 kilometres off Bagaces, (the highest in Cordillera Guanacaste). It contains 5 cones along a North-East trending line. The only reported historical eruptive activity was a small steam explosion in 1946. On its slopes a few mud bumbling pots and thermal springs. On the volcanoe foot there is Costa Rica`s Electricity Institute geothermal project. In the middle of XIX century there was a trial of organizing German colonization. On cloudless days, from the top it`s possible to see Nicaragua Lake.

Volcano Orosi

[1.487 m.a.s.l.]. The legent has it that in the past on the top of volcano climbed the Indian military groupe. There they were spotted by an earthquake. One of them was expected to screamed that it`s a sign for silver presence. From the depths of the volcano came a powerful, echoing voice replying, "Plata, no; oro, si." ("Silver no, Gold Yes."). It`s crater is covered by forests. The first study of this volcano was made by Carlos Sapper in 1899.

Volcano Platanar

(2.183 m.a.s.l.). A volcanic peak lied at the northernmost end of Cordillera Central, 7 kilometres south-east of the town of Quesada. It belongs to Juan Castro Blanco National Park. There is no clear evidences of uruptive activity of that peak, but the thin layers of ashes covering in the eastern slope testified its activity within last few centuries. On its northern slope, flow the thermal springs.

Volcano Poas

[2706 m.a.s.l]. It has three craters, only one active. It measures 1500 metres lengh (the second widest crater of the world), and 300 metres of depth. On its bottom there is the most active bubling lake in the world. Its geiser eruptions shoot at 40 metres above. To the north from the main crater, Von Frantzius crater (the oldest one) is situated. The third crater Botos is filled with blue water lake and ringed by thick forests. The first mention of Poas volcanic activity dates back to 1834. Its eruption from 1889 made an earthquake, due to which, a piece of volcanic wall was torn off and a deep hole filled with water was made. (Fraijanes Lake). During the eruption from 1910, the ash cloud was shot 8.000 metres into the air. In 1952-1954 there were similar clouds ashes substituted by deep tremors. Since 1989 the increase of gas emissions has been observed. It`s in charge of acid rains, that destroyed the strawberry plantations on the western side of volcanoe.

Volcano Porvenir

[2.267 m.a.s.l.]. Large stratowulcano lying within the Chocosuela caldera. Its summit crater contains a small cone. A thin layer of ash suggest that an eruption occured within the past few thousand years. It belongs to Juan Castro Blanco National Park.

Volcano Rincon de la Vieja

It was appeared about millions years ago. It means "the corner of old lady" and is attributed to indigenous people of the Guatuso tribe living on the eastern side of the volcano who believed that an old witch lived on top of the mountain and would send columns of smoke into the air whenever she got annoyed. It has 9 craters and is considered as the third in respesct of activity volcanoe in Costa Rica. It`s main crater has elipse shape, 500 metres of width and 100 metres of depth. On its bottom there is a hole with bumbling 250 Ceisius lava. In April 2000 the Canadian tourist has fallen to there for three days. To the east of crater there us a lake, waterfalls and bubling holes. The last vital eruptions took place in 1966-1970. They were accompanied by clouds of ashes, earthquakes and tremors. The lighter eruptions took part in 1984, 1891 and 1996.

Volcano Tenorio

From its top spreads the sight for Guatuso and San Carlos lowlands. It`s covered with savannas, rain forest (at mid elevation) and cloud forest (above). From its slopes snakes down the Rio Frio. A legend exists of an eruption in 1816, but the volcano was observed to be densely forested in 1864 and is not considered to have erupted in historical time. Since 1989 it has been under a pre-feasibility study to determine its geothermal potential. In 1998 the vicinity of the volcano was hit by the 1 R scale earthquake.

Volcano Turrialba

It`s the most easterntip volcanoe of the Cordillera Central (the second volcanoe in the country in respect of metres above sea level-3.339). It has been active since 6.300 BC. In colonial times that was nicknamed by Spaniards as Torre Alba "white tower", because of its eruptions gave the impression of a huge white tower. It has three craters. To the main of them doesn`t lead any way. The catastrophic eruptions happened also in 1723, 1847, 1853, 1855 and 1861. Now the scientists claim its new eruption might be expected. In March 2001 the tremors were heard and felt in the volcanoe vicinity and that made the inhabitants of nearby afraid.

2004; SLUPSK; Rafal Cezary Piechocinski