San Joaquin

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 3.35°N
  • 8.63°E

  • 2009 m
    6590 ft

  • 224003
  • Latitude
  • Longitude

  • Summit

  • Volcano

The Global Volcanism Program has no activity reports for San Joaquin.

The Global Volcanism Program has no Weekly Reports available for San Joaquin.

The Global Volcanism Program has no Bulletin Reports available for San Joaquin.

Basic Data

Volcano Number

Last Known Eruption



Unknown - Evidence Credible

2009 m / 6590 ft


Volcano Types

Pyroclastic cone(s)

Rock Types

Basalt / Picro-Basalt
Trachybasalt / Tephrite Basanite

Tectonic Setting

Continental crust (> 25 km)


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

Geological Summary

San Joaquin, also known as Pico Biao or Pico do Moka, is a 2009-m-high basaltic shield volcano on the SE side of Bioko (Fernando Poo) Island. A small lake-filled caldera cuts the summit of the forested shield volcano, and a crater lake lies on the NE flank of the volcano. San Joaquin was classified as having been active during the last 2000 years (International Association of Volcanology and Chemistry of the Earth's Interior, 1973), although little is known about its geologic history.


The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Deruelle B, Kambou R, Joron J-L, 1990. New petrological data on volcanic rocks of Bioko Island (Equatorial Guinea). IAVCEI 1990 Internatl Volc Cong, Mainz, Abs, (unpaginated).

Fitton J G, 1987. The Cameroon line, West Africa: a comparison between oceanic and continental alkaline volcanism. In: Fitton J G and Upton B G J (eds) {Alkaline Igneous Rocks}, Geol Soc Amer Spec Pub 30: 273-291.

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

Liniger-Goumaz M, 1988. Historical Dictionary of Equatorial Guinea. Metuchen, New Jersey: Scarecrow Press, African Historical Dictionaries, no 21.

Vincent P M, 1992. (pers. comm.).

The Global Volcanism Program is not aware of any Holocene eruptions from San Joaquin. If this volcano has had large eruptions (VEI >= 4) prior to 10,000 years ago, information might be found on the San Joaquin 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.


Biao, Pico | Moka, Pico do

Photo Gallery

A dark-colored lake partially fills a small caldera (top-center) occupying the summit of San Joaquin volcano in this NASA Landsat view with north to the top. This basaltic shield volcano, also known as Pico Biao, lies on the SE side of Bioko (Fernando Poo) Island in the Gulf of Guinea. Part of the broad summit caldera of neighboring San Carlos volcano can be seen at the left.

NASA Landsat7 image (

Smithsonian Sample Collections Database

There are no samples for San Joaquin in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

Affiliated Sites

Large Eruptions of San Joaquin 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).
MODVOLC - HIGP MODIS Thermal Alert System Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.
MIROVA Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.