Miravalles Volcano

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Miravalles Volcano
Miravalles Volcano in 1988
Highest point
Elevation2,028 m (6,654 ft)[1]
ListingList of volcanoes in Costa Rica
Coordinates10°44′54″N 85°09′10″W / 10.74833°N 85.15278°W / 10.74833; -85.15278[1]
Geography
Miravalles Volcano is located in Costa Rica
Miravalles Volcano
Miravalles Volcano
Parent rangeCordillera de Guanacaste
Geology
Rock age1.5 Myr
Stratovolcano
Volcanic arcCentral America Volcanic Arc
Last eruptionSeptember 1946[1]

The Miravalles Volcano is an andesitic stratovolcano[1] within the Miravalles Protected Zone,[2] a nature reserve in Costa Rica. The Miravalles Volcano reaches an elevation of 2,028 metres (6,654 ft) and is the tallest volcano in the Cordillera de Guanacaste mountain range.[3] It is the site of the most developed and productive geothermal field in Costa Rica,[1] with a plant capable of generating 161.5[4] or 162.7 MW of power.[5][6]

Geology

Miravalles is one of five post-caldera cones within the 15-by-20-kilometre (9.3 by 12.4 mi) Guayapo caldera, the latter formed between about 1.5 and 0.6 million years ago.[1] There are two andistic lava flows on its northern flank, one descending west towards a geothermal power plant (see section below), the other to the north into the Guayapo caldera.[7] Lava flows also cover the western and southwestern flanks of the Miravalles complex.[1] There are parasitic cones near the crater at altitudes of 5,098 feet (1,554 m), 5,059 feet (1,542 m) and 3,280 feet (1,000 m).[7] Twin cones named Cerro la Giganta stand at 4,888 feet (1,490 m).[7] On the southern face, there are three small cones, among them Gota de Agua at 3,550 feet (1,080 m) and Espiritu Santo at 3,212 feet (979 m).[7]

The only reported historical eruptive activities are a small steam explosion on the south-western flank in 1946 and an erruption c. 5050 BCE.[1]

Geothermal power generation

In response to the 1973 and 1979 oil crises, Costa Rica, with little in the way of fossil fuel resources, began considering alternative energy sources.[8] The Instituto Costarricense de Electricidad (Costa Rican Institute of Electricity, ICE) conducted an evaluation of the country's geothermal resources between November 1987 and October 1988; Miravalles was selected as one of three high-priority areas.[9] Three deep exploratory wells were dug from 1979 to 1980; they all indicated that there was a "liquid-dominated reservoir" covering 15 square kilometres (5.8 sq mi) under the volcano's southwestern slope.[8] Six more wells were dug between 1984 to 1986, followed by 20 more.[8]

A hybrid power plant was constructed and commissioned in March 1994, with a capacity of 161.5[4] or 162.7 megawatts.[5] There are five power plants in four powerhouses, 48.5 kilometres (30.1 mi) of pipelines and a total of 61 wells, consisting of production, injection and observation wells.[4] A 50-kilometre (31 mi) power line connects it to the main electrical transmission line.[5] It is the most developed and productive geothermal field in the country, though it has reached its extraction rate ceiling.[4] It is owned by ICE.[5]

References

  1. "Miravalles". Global Volcanism Program. Smithsonian Institution. Retrieved 11 March 2010.
  2. "Zona Protectora Miravalles --- 11672 ha". Ministry of Environment and Energy (Costa Rica). Retrieved 17 May 2026.
  3. Firestone, Matthew; Wendy Yanagihara; Mara Vorhees (2008). Costa Rica (8th ed.). London: Lonely Planet. p. 206. ISBN 978-1-74104-885-8.
  4. "Costa Rica Geothermal Energy Market Overview" (PDF). ThinkGeoEnergy. April 2021. p. 3. Retrieved 17 May 2026.
  5. "Power plant profile: Miravalles, Costa Rica". power-technology.com. 21 October 2024. Retrieved 17 May 2026.
  6. Stater, Adam. "The Miravalles Volcano".
  7. Bergoeing, Jean Pierre (2017). Geomorphology and Volcanology of Costa Rica. Elsevier. pp. 162–163. ISBN 978-0-12-812067-5. Retrieved 17 May 2026.
  8. DiPippo, Ronald (2012). Geothermal Power Plants (Third ed.). Butterworth-Heinemanne. pp. 332–334. ISBN 978-0-08-098206-9. Retrieved 17 May 2026.
  9. Dagoberto Herrera Cabezas (1990). "Gravity and Magnetic Assessment of the Tenorio Area, Costa Rica" (PDF). p. 6. Retrieved 17 May 2026.