Ankaratra Field

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 19.4°S
  • 47.2°E

  • 2644 m
    8672 ft

  • 233015
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Ankaratra Field.

The Global Volcanism Program has no Weekly Reports available for Ankaratra Field.

The Global Volcanism Program has no Bulletin Reports available for Ankaratra Field.

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude
233015

Unknown - Evidence Credible

2644 m / 8672 ft

19.4°S
47.2°E

Volcano Types

Pyroclastic cone(s)
Lava dome(s)

Rock Types

Major
Trachybasalt / Tephrite Basanite
Foidite
Andesite / Basaltic Andesite
Trachyte / Trachyandesite
Phonolite

Tectonic Setting

Intraplate
Continental crust (> 25 km)

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
123,192
123,192
413,328
5,184,370

Geological Summary

The Ankaratra volcanic field is the most prominent and volcanologically diverse on Madagascar. It covers a 100-km-long area in central Madagascar between Avivonimamo and Antsirabe. Activity at the Ankaratra volcanic massif took place from the Miocene until the very recent Quaternary (Besairie, 1973). Trachytic lava domes were erupted during the initial stage and massive fissure eruptions created a series of tectonic lakes. The latest activity occurred in the southern part of the massif and produced well-preserved strombolian basanitic cinder cones. Vulcanian eruptions formed several lake-filled craters. Hot springs occur at Ranomafana.

References

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

Battistini R, 1962. Le massif volcanique de l'Itasy (Madagascar). Annales Geog, 384: 167-178.

Besairie H J, 1973. Precis de geologie Malgache. Annales Geol Madagascar, 36: 1-141.

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

Antsirable

Cones

Feature Name Feature Type Elevation Latitude Longitude
Antsirabe Cone
Betafo Cone
Tritriva Cone
Vohitra Cone

Craters

Feature Name Feature Type Elevation Latitude Longitude
Andraikiba Crater - Cone

Thermal

Feature Name Feature Type Elevation Latitude Longitude
Ranomafana Thermal

Photo Gallery


The Ankaratra volcanic field in central Madagascar consists of trachytic lava domes, fissure vents, basanitic cinder cones, and maars. The volcanic field is one of the largest on the island and covers a 100-km-long area in central Madagascar. Hot springs occur at Ranomafana. North is to the top in this NASA Landsat image.

NASA Landsat7 image (worldwind.arc.nasa.gov)

Smithsonian Sample Collections Database


A listing of samples from the Smithsonian collections will be available soon.

Affiliated Sites

Large Eruptions of Ankaratra Field 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.