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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 12.98°N
  • 87.57°W

  • 872 m
    2860 ft

  • 344010
  • Latitude
  • Longitude

  • Summit

  • Volcano

The Global Volcanism Program has no activity reports for Cosigüina.

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

Index of Monthly Reports

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

12/1980 (SEAN 05:12) No fumarolic activity visible

04/1999 (BGVN 24:04) Temperature and pH measurements of the fresh crater lake

04/2003 (BGVN 28:04) Earthquake swarm in September 2002

Contents of Monthly Reports

All information contained in these reports is preliminary and subject to change.

12/1980 (SEAN 05:12) No fumarolic activity visible

No fumarolic activity was visible from the rim [during a visit between mid-November. and early December.]

Information Contacts: R. Stoiber, S. Williams, H.R. Naslund, L. Malinconico, M. Conrad, Dartmouth College; S. Bonis, IGN, Guatemala; A. Aburto, D. Fajardo, Instituto de Investigaciones Sísmicas.

04/1999 (BGVN 24:04) Temperature and pH measurements of the fresh crater lake

A team from the Université de Montréal, Open University, and INETER visited Cosigüina volcano on 25 February 1999. The summit crater contains a roughly circular lake with a dark green color. The lake has a maximum diameter of ~1.5 km and occupies about 90% of the crater bottom, the remaining area being covered with dense vegetation. The surface temperature of the lake measured from the NW shore with a thermocouple was ~27°C, slightly lower than the ambient air temperature (~31°C) measured at noon. The pH of the lake surface water measured directly with a glass electrode was slightly alkaline (pH ~7.5). Feeble, diffuse gas was bubbling at the surface of the lake along the NW shore. Temperature of the ground in these areas reached a maximum of ~80°C. There was no sign of recent hot spring or fumarolic activity in the crater. One spring located on the E flank of the volcano near the village of Potosi had a temperature of ~42°C, a flow rate of ~2 l/s and a total dissolved solids content 100 mg/kg. Apparently, it is the only permanent, visible hydrothermal manifestation near the volcano.

Information Contacts: Pierre Delmelle, Département de Géologie, Université de Montréal, Montréal, Québec H3C 3J7, Canada (Email:; Glyn Williams-Jones, Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, England, United Kingdom (Email:; José Garcia Alavarez, Martha Navarro, and Wilfried Strauch, INETER, Apartado Postal 2110, Managua, Nicaragua (Email:

04/2003 (BGVN 28:04) Earthquake swarm in September 2002

In September 2002 an earthquake swarm was registered near Cosigüina. This swarm was the first to be recognized at that volcano in the 27 years of the existence of Nicaragua's seismic network. The historical seismic record contains no evidence of the type of cluster that occurred in September 2002, although there was seismic activity in 1951 that could have been of local origin (see below).

The seismicity began on 4 September, with M 2.4-3.6 events. The main earthquake occurred on 9 September with a magnitude of 3.9. The last event occurred on 16 September with a magnitude of 3.7. A total of 34 earthquakes occurred to the N of Cosigüina volcano. Unfortunately, the seismic station at the volcano failed to function due to radio signal transmission problems. Seismic readings were also obtained from the National System of Territorial Studies of El Salvador (SNET) for 31 earthquakes. Epicenters of the earthquakes, located with the readings obtained by the seismic networks of the Instituto Nicaragüense de Estudios Territoriales (INETER) and SNET, were concentrated in a zone approximately 4-5 km N and W of the crater (figure 1). The distribution, along a SW-NE axis, might be simply a product of the geometry of the configuration of seismic stations with which the events were located.

Figure 1. Epicentral map of the earthquakes located N of Cosigüina volcano. September 2002. Black triangle indicates approximate summit location. Courtesy of INETER.

Randy White (USGS) indicated to INETER that the seismicity seems to have been of the volcano-tectonic type, caused by an intrusion of magma, based on several observations: 1) the two stages of the cluster on 4-6 and 9 September showed a release of similar seismic energy; 2) In the two stages there were many similarly sized events; 17 with a magnitude of 3.0 or less, but none greater than 3.9; 3) The maximum magnitude increased several times; and 4) The distribution of energy was highly unusual for tectonic seismicity. Apparently there were several groups of one or a few events in intervals of 5-7 hours. Regular pulsations are typical for volcanic earthquake swarms that last more than several hours.

INETER volcanologist Pedro Perez investigated the volcano on 12 September, but saw nothing anomalous. He also conducted interviews with local residents, went to the summit crater, and took measurements of thermal waters at the foot of the volcano. Within the crater walls, landslides were observed in the E, S, and W portions. Residents in the Marañonal, Potosí, Punta Ñata, and Apascali sectors did not feel the earthquakes.

Seismicity in August 1951. The following description is based on news reports compiled by INETER (The News, 1951 Ago. 07; The Press, 1951 Ago. 04, 05, 07, 09, 18).

In August 1951 there was strong seismic activity in western Nicaragua and southwestern Honduras. On 2 August one of a series of strong events produced a 200-m-long crack near Cosigüina that spewed large amounts of water, flooding the region. The seismic shocks also demolished three houses in Chinandega. These earthquakes were felt more strongly to the W and diminished to the N and in the direction of Managua. The population in these areas slept outside their homes for many days. The people of these sectors, mainly the western population, felt continuous and violent seismic shocks until 8 August. On 17 August a strong tremor shook the western region and Managua. Apparently, this seismic activity produced more than 100 events, not all of which were felt by all residents.

Information Contacts: Virginia Tenorio and Wilfried Strauch, Instituto Nicaragüense de Estudios Territoriales (INETER), Apartado 1761, Managua, Nicaragua (Email:,, URL:

Cosigüina is a low basaltic-to-andesitic composite volcano that is isolated from other eruptive centers in the Nicaraguan volcanic chain. The 872-m-high stratovolcano forms a large peninsula extending into the Gulf of Fonseca at the western tip of the country. Cosigüina (also spelled Cosegüina) has a pronounced somma rim on the northern side; a young summit cone of Cosigüina rises 300 m above the northern somma rim and buries the rim on other sides. The younger cone is truncated by a large elliptical prehistorical summit caldera, 2 x 2.4 km in diameter and 500 m deep, with a lake at its bottom. Lava flows predominate in the caldera walls, although lahar and pyroclastic-flow deposits surround the volcano. In 1835 Cosigüina was the source of a brief, but powerful explosive eruption that was Nicaragua's largest during historical time. Ash fell as far away as México, Costa Rica, and Jamaica, and pyroclastic flows reached the Gulf of Fonseca.

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1859 Aug 25 Unknown Confirmed   Historical Observations
1852 Dec Unknown Confirmed 2 Historical Observations
1835 Jan 20 1835 Jan 25 (?) Confirmed 5 Historical Observations
[ 1809 Mar 28 ] [ 1809 Mar 31 ± 1 days ] Uncertain 2  
1709 (?) Unknown Confirmed   Historical Observations
[ 1609 ] [ Unknown ] Uncertain    
1500 (?) Unknown Confirmed   Radiocarbon (uncorrected)

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.


Feature Name Feature Type Elevation Latitude Longitude
Filete el Yankee Cone 12° 58' 0" N 87° 32' 0" W
Filete la Salvia Cone 12° 59' 0" N 87° 39' 0" W
San Juan, Loma Stratovolcano 12° 58' 0" N 87° 31' 0" W

Feature Name Feature Type Elevation Latitude Longitude
Barranco, El Maar 13° 6' 0" N 87° 33' 0" W
Filete Cresta Montosa Caldera

Feature Name Feature Type Elevation Latitude Longitude
Chanchos, Los Dome 12° 56' 38" N 87° 33' 11" W

Feature Name Feature Type Elevation Latitude Longitude
Batidoras, Las Thermal
The profile of Cosigüina is not particularly impressive when viewed from its NE flank along the coast of the Gulf of Fonseca near the town of Potosí. The broad low-angle slopes of Cosigüina rise only 872 m above the coast and give little hint of the dramatic caldera that cuts the summit. Pyroclastic flows from the 1835 eruption reached the northern coast of the 20-km-wide Cosigüina Peninsula and formed new ephemeral islands in the Gulf of Fonseca.

Copyrighted photo by Dick Stoiber, 1978 (Dartmouth College).
The summit of Cosigüina volcano, seen here from the west with the Gulf of Fonseca in the background and the border with Honduras at the upper left, contains a 2 x 2.4 km wide caldera with steep-sided, 500-m-high walls. The upper flanks of the volcano are only partially forested after a devastating eruption in 1835 produced pyroclastic flows and surges that reached the coast and fountain-fed lava flows that blanketed the upper eastern and western flanks. The peak in the distance below the right side of the wing is San Cristóbal volcano.

Photo by Jaime Incer, 1981.
Cosigüina, seen here from the east, is a low basaltic-to-andesitic composite volcano that forms a large peninsula at the NW tip of Nicaragua along the Gulf of Fonseca. The 872-m-high volcano has a pronounced somma rim, which forms the ridge seen here at the right behind the far crater rim. The younger cone is truncated by a large elliptical prehistorical summit caldera 2 x 2.4 km in diameter and 500 m deep, which is now filled by a lake. It was the source of a major explosive eruption in 1835, Nicaragua's largest during historical time.

Photo by Jaime Incer, 1981.
The steep-sided caldera walls of Cosigüina volcano rise 500 m above a lake on the caldera floor. Inter-bedded gray lava flows and brownish pyroclastic deposits forming the pre-caldera stratovolcano are exposed in the far wall. Observers of Cosigüina prior to the catastrophic 1835 eruption described the volcano as being of low height, with a flat top, suggesting that the caldera was in existence prior to the eruption.

Photo by Jaime Incer.
The broad Cosigüina stratovolcano (also spelled Cosegüina), is seen here from the SE across the Gulf of Fonseca. Cosigüina is the NW-most of a chain of active volcanoes stretching across Nicaragua. The 872-m-high volcano is truncated by a 2 x 2.4 km wide caldera that is filled by a lake. In 1835 Cosigüina was the source of Nicaragua's largest historical eruption, which produced detonations heard as far away as Guatemala. Pyroclastic flows and surges reached the Gulf of Fonseca and produced ephemeral islands.

Photo by Jaime Incer.
A dramatic aerial view from the NW shows Cosigüina volcano with its 2.4-km-wide caldera. One of Central America's largest historical eruptions began on January 20, 1835. Detonations were heard in Jamaica, Venezuela, and Colombia, and ash fell throughout Central America and southern México. Pyroclastic flows and surges reached the Gulf of Fonseca (background), and fountain-fed lava flows mantled portions of the upper flanks. Although the eruption devastated croplands and livestock, there were few human fatalities.

Photo by Jaime Incer, 1991.
Cosigüina volcano forms the northern half of a 25-km-wide peninsula extending NW-ward into the Gulf of Fonseca. A 2-km-wide caldera, partially filled by a lake, truncates the summit of the volcano, and the scarp of a larger older caldera is visible to the NW. Pyroclastic flows from the catastrophic 1835 eruption, the largest in Nicaragua during historical time, reached the Gulf of Fonseca. The volcanic island of Meanguera in the El Salvador side of the Gulf of Fonseca is visible at the top left.

NASA Space Shuttle image ISS004-E-9143, 2002 (
The steep-walled, lake-filled summit caldera of Cosigüina volcano is prominent in this NASA Space Shuttle image with north to the upper left. Bahia el Rosario lies to the right of the elongate peninsula at the upper left with Punta San Jose at its tip, and the town of Potosi is at the top center. The scarp of an older caldera rim forms Filete Cresta Montosa, the semi-arcuate ridge below the summit caldera. This scarp continues in a more subdued form to the northern side of the volcano.

NASA Space Shuttle image ISS006-E-51438, 2003 (

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.

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.

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

Incer J, 1987. . (pers. comm.).

Kutterolf S, Freundt A, Perez W, 2008. Pacific offshore record of plinian arc volcanism in Central America: 2. Tephra volumes and eruptive masses. Geochem Geophys Geosyst, 8: Q02S02, doi:10.1029/2007GC001791.

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.

Scott W E, Gardner C, Devoli G, Alvarez A, 2006. The A.D. 1835 eruption of Volcan Cosiguina, Nicaragua: a guide for assessing local 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: 167-187.

Self S, Rampino M R, Carr M J, 1989. A reappraisal of the 1835 eruption of Cosiguina and its atmospheric impact. Bull Volc, 52: 57-65.

van Wyk de Vries B, 1993. Tectonics and magma evolution of Nicaraguan volcanic systems. Unpublished PhD thesis, Open Univ, Milton Keynes, 328 p.

Williams R L (ed), 1972. The geology of western Nicaragua. Parsons Corp Final Technical Rpt, 4:1-221.

Volcano Types

Lava dome(s)

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Andesite / Basaltic Andesite
Basalt / Picro-Basalt


Within 5 km
Within 10 km
Within 30 km
Within 100 km

Affiliated Databases

Large Eruptions of Cosigüina 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.