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Arenal Volcano, in Spanish , is an active andesitic stratovolcano in north-western Costa Rica around 90 km northwest of San José, in the province of Alajuela, canton of San Carlos, and district of La Fortuna. The Arenal volcano measures at least high. It is conically shaped with a crater in diameter. Geologically, Arenal is considered a young volcano and it is estimated to be less than 7,500 years old. It is also known as "Pan de Azúcar", "Canaste", "Volcan Costa Rica", "Volcan Río Frío" or "Guatusos Peak". The volcano was dormant for hundreds of years and exhibited a single crater at its summit, with minor fumaroles activity, covered by dense vegetation. In 1968 it erupted unexpectedly, destroying the small town of Tabacón. Due to the eruption three more craters were created on the western flanks but only one of them still exists today. Since October 2010, Arenal has become dormant, with no explosions since December 2010. ==Geographic setting and description== Arenal is one of seven historically active Costa Rican volcanoes along with Poás, Irazú, Miravalles, Orosí, Rincón de la Vieja complex, and Turrialba. It was Costa Rica's most active volcano until 2010, and one of the ten most active volcanoes in the world. It has been studied by seismologists for many years. The volcano is located at the center of Arenal Volcano National Park in the northern zone of the country, southwest of the La Fortuna district in San Carlos (canton), Costa Rica. The temperature varies from in the high areas to in the low areas and the annual rainfall is around . Arenal Volcano area is an important watershed for the Arenal Lake Reservoir. The reservoir's water is used for hydroelectric power. It is also connected to the national system. Arenal has a good number of eruptive vents. Chato is a dormant stratovolcanic cone. It is believed Chato first erupted 38,000 years ago during the Pleistocene period and last erupted about 3,500 years ago.〔 Chatito is a lava dome with an elevation of . Espina is another lava dome.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Arenal Volcano」の詳細全文を読む スポンサード リンク
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