Ascension

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  • United Kingdom
  • Atlantic Ocean
  • Stratovolcano
  • Unknown - Evidence Credible
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 7.95°S
  • 14.37°W

  • 858 m
    2814 ft

  • 385050
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Ascension.

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

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

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude
385050

Unknown - Evidence Credible

858 m / 2814 ft

7.95°S
14.37°W

Volcano Types

Stratovolcano
Pyroclastic cone(s)
Lava dome(s)

Rock Types

Major
Basalt / Picro-Basalt
Trachybasalt / Tephrite Basanite
Trachyandesite / Basaltic trachy-andesite
Trachyte / Trachyandesite
Rhyolite

Tectonic Setting

Rift zone
Oceanic crust (< 15 km)

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
614
1,149
1,149
1,149

Geological Summary

Ascensión Island, located just west of the Mid-Atlantic Ridge, was discovered on Ascensión Day, 1501, by the Portuguese navigator Joao da Nova. Ascensión is the broad emergent summit of a massive stratovolcano that rises 3000 m above the sea floor. The isolated island, 1130 km from the nearest land, is dotted with more than 100 youthful parasitic cones and lava domes, many aligned along two fissures. Basaltic rocks dominate on the 858-m-high island, although trachytic lava domes are also present, mostly on the eastern side. Although no eruptive activity has occurred since its discovery during the 16th century, many volcanic features on Ascensión have a very youthful appearance. Two of the youngest lava flows were erupted from flank vents and reached the sea on the northern and southern coasts.

References

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

Bell J D, Atkins F B, Baker P E, Smith D G W, 1972. Notes on the petrology and age of Ascension Island, south Atlantic (abs). Eos, Trans Amer Geophys Union, 53: 168.

Daly, Reginald A., 1925. The Geology of Ascension Island. Proceedings of the American Academy of Arts and Sciences, 60: 3-80.

Harris C, 1983. The petrology of lavas and associated plutonic inclusions of Ascension Island. J Petr, 24: 424-470.

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

Mitchell-Thome R C, 1970. Geology of the South Atlantic islands. Berlin: Gebruder Borntraeger, 350 p.

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


Cones

Feature Name Feature Type Elevation Latitude Longitude
Cat Hill Cone - Crater 85 m
Crater Cliff Cone 57 m
Hayes Hill Cone 32 m
Lady Hill Cone 360 m
Mountain Red Hill Cone 544 m
Perfect Crater Pyroclastic cone 311 m
Round Hill Cone 137 m
Sisters Peak Cone 445 m
Sisters Red Hill Cone 276 m
South Gannet Hill Cone 228 m
South Red Crater Pyroclastic cone 166 m
Southwest Red Hill Pyroclastic cone 223 m
Spoon Crater Cone - Crater 362 m
The Peak Pyroclastic cone 858 m
Thistle Hill Cone 329 m
Travellers Hill Cone 357 m

Craters

Feature Name Feature Type Elevation Latitude Longitude
Butt Crater Crater - Cone 226 m
Dark Slope Crater - Cone 233 m
Devils Cauldron Caldera 457 m
East Crater Crater - Cone 226 m
Green Top Crater Crater
Hollands Crater Crater - Cone 199 m
Horseshoe Crater Crater - Cone 120 m
Saddle Crater Crater - Cone 129 m
Southeast Crater Crater - Cone 1146 m
Street Crater Crater - Cone 240 m
Table Crater Crater - Cone 195 m
Upper Valley Crater Crater - Cone 245 m

Domes

Feature Name Feature Type Elevation Latitude Longitude
Bears Back Dome 241 m
Boatswain Bird Islet Dome 98 m
Cross Hill Dome 265 m
Green Mountain Dome 759 m
Little White Hill Dome 168 m
Ragged Hill Dome 287 m
Riding School Dome 244 m
Weather Post Dome 607 m
White Hill Dome 525 m
Wig Hill Dome 145 m

Photo Gallery


Ascensión Island, located just west of the Mid-Atlantic Ridge, was discovered on Ascención Day, 1501, by the Portuguese navigator Joao da Nova. Today a center for telephone and radio communications and satellite tracking, Ascensión is the summit of a massive stratovolcano rising 3000 m above the sea floor. The isolated island, about 1130 km from the nearest land, has had no historical eruptions, but is dotted with more than 100 youthful parasitic cones and lava domes. Young lava flows can be seen along the NW and SW coasts.

NASA Space Shuttle image, 2003 (http://eol.jsc.nasa.gov/).
A view to the NW from Green Mountain shows The Sisters (left) and Perfect Crater (right-center), cinder cones on the flanks of the Ascensión Island volcano, which lies just west of the Mid-Atlantic Ridge. The isolated island is dotted with more than 100 youthful parasitic cones and lava domes, many aligned along two fissures. Although no eruptive activity has occurred since its discovery during the 16th century, many volcanic features on Ascensión have a very youthful appearance.

Photo by Jon Davidson (University of Durham).

Smithsonian Sample Collections Database


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

Affiliated Sites

Large Eruptions of Ascension 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.