Orosi

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 10.98°N
  • 85.473°W

  • 1659 m
    5442 ft

  • 345010
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Orosi.

The Global Volcanism Program has no Weekly Reports available for Orosi.

The Global Volcanism Program has no Bulletin Reports available for Orosi.

Orosí is one of a cluster of four eroded and vegetated cones in the Guanacaste Range at the NW corner of Costa Rica. Volcán Orosí itself has a conical shape as viewed from the north or west, but its flanks are heavily eroded. The complex includes Orosí, Orosilito, Volcán Pedregal, and Cacao. The highest peak of the volcanic complex is 1659-m-high Volcán Cacao, 5.5 km SE of Orosí. The summit of Cacao is cut by two large horseshoe-shaped calderas breached to the SW and east related to edifice collapse. The age of the latest activity of the Orosí complex is not known. Historical eruptions were reported from Orosí in 1844 and 1849, but even at the time of the first volcanological observations at the end of the 19th century, Orosí was overgrown with large trees, and the eruptions may actually have been from neighboring Rincón de la Vieja volcano. The latest documented volcanic activity at Orosí produced mudflows (perhaps secondary) about 3500 years ago.

The Global Volcanism Program is not aware of any Holocene eruptions from Orosi. If this volcano has had large eruptions (VEI >= 4) prior to 10,000 years ago, information might be found on the Orosi page in the LaMEVE (Large Magnitude Explosive Volcanic Eruptions) database, a part of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.


Synonyms

Orosí-Cacao

Cones

Feature Name Feature Type Elevation Latitude Longitude
Cacao Stratovolcano 1659 m 10° 57' 7" N 85° 27' 4" W
Gongora Cone
Orosilito, Volcán Stratovolcano 1200 m
Pedregal Stratovolcano 1100 m
The highest peak of the Orosí volcanic complex is Volcán Cacao, which is seen in this view from the SW. The summit of Cacao, 5.5 km SE of Orosí, was breached to the SW as a result of edifice collapse. Orosí is one of a cluster of four eroded and vegetated cones in the Guanacaste Range at the NW corner of Costa Rica. Volcán Orosí itself has a conical shape as viewed from the north or west, but its flanks are heavily eroded. The age of the latest activity of the Orosí complex is not known.

Photo by Cindy Stine, 1989 (U.S. Geological Survey).
The SW side of Volcán Cacao, located at the SE end of the Orosí volcanic massif, is cut by an arcuate depression created during a massive slope failure in which the summit of the volcano was removed. The vertical light-colored stripes on the upper edifice are rockslide scars. The latest eruptive activity at the Orosí complex consisted of post-collapse lava domes and flows from Cerro Cacao.

Photo by Cindy Stine, 1989 (U.S. Geological Survey).
The Orosí volcanic complex is seen here from the north, with the summit of Orosí in the clouds at the right and Volcán Cacao, the highest peak of the complex, at the left. Orosí is one of a cluster of four eroded and vegetated cones in the eastern part of Guanacaste National Park at the NW corner of Costa Rica. Volcán Orosí itself has a conical shape as viewed from the north or west, but its flanks are heavily eroded. Reported eruptions of Orosí in 1844 and 1849 may actually have been from Rincón de la Vieja volcano.

Photo by William Melson (Smithsonian Institution).
The low hill in the background is part of a massive debris-avalanche deposit formed by collapse of Volcán Cacao (also called Cerro Cacao). The avalanche swept onto the flat-lying Pacific coastal plain as far as the Central American highway, near where this photo was taken.

Photo by Lee Siebert, 1998 (Smithsonian Institution).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

Alvarado G E, 1989. Los Volcanes de Costa Rica. San Jose, Costa Rica: Universidad Estatal a Distancia, 175 p.

Alvarado G E, 2000. Volcanes de Costa Rica: su geologia, historia y riqueza natural. San Jose, Costa Rica: EUNED, 269 p.

Alvarado G E, Vega E, Chaves J, Vasquez M, 2004. Los grandes deslizamientos (volcanicos y no volcanicos) de tip debris avalanche en Costa Rica. Rev Geol Amer Central, 30: 83-99.

Alvarado-Induni G E, 2005. Costa Rica, Land of Volcanoes. San Jose, Costa Rica: EUNID, 306 p.

Barquero-H J, Saenz-R R, 1987. Aparatos volcanicos de Costa Rica. Heredia, Costa Rica: OVSICORI-UNA, 1:750,000 map and volcano list.

Carr M J, 1984. Symmetrical and segmented variation of physical and geochemical characterisitics of the Central American volcanic front. J Volc Geotherm Res, 20: 231-252.

Cecchi E, van Wyk de Vries B, Lavest J-M, 2005. Flank spreading and collapse of weak-cored volcanoes. Bull Volc, 67: 72-91.

Chiesa S, Alvarado G E, Pecchio M, Corella M, Zanchi A, 1994. Contribution to petrological and stratigraphical understanding of the Cordillera de Guanacaste lava flows, Costa Rica. Rev Geol Amer Central, 17: 19-43.

Chiesa S, Bettoni M, Confortini F, Invernici N, Madesani R, Suardi M, 1996. Breva resena sobre la geologia de los Parques Nacionales Santa Rosa y Guanacaste. Rothschildia, 3(1): 1-5.

Chiesa S, Confortini F, Madesani R, 1998. Geologia del Area de Conservacion de Guanacaste. Rothschildia, 5(2): 1-36.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Kerle N, van Wyk de Vries B, 2001. The 1998 debris avalanche at Casita Volcano, Nicaragua; investigation of structural deformation as the cause of slope instability using remote sensing. J Volc Geotherm Res, 105: 49-63.

Mooser F, Meyer-Abich H, McBirney A R, 1958. Central America. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 6: 1-146.

Sapper K, 1925. The Volcanoes of Central America. Halle: Verlag Max Niemeyer, 144 p.

Siebert L, Alvarado G E, Vallance J W, van Wyk de Vries B, 2006. Large-volume volcanic edifice failures in Central America and associated hazards. In: Rose W I, Bluth G J S, Carr M J, Ewert J W, Patino L C, Vallance J W (eds), Volcanic hazards in Central America, {Geol Soc Amer Spec Pap}, 412: 1-26.

Volcano Types

Stratovolcano(es)

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Major
Andesite / Basaltic Andesite
Basalt / Picro-Basalt

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
43
1,024
31,463
588,207

Affiliated Databases

Large Eruptions of Orosi Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.