Ascension

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  • United Kingdom
  • Atlantic Ocean
  • Stratovolcano
  • Unknown - Undated Evidence
  • 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.

Geological Background


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.

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).

References


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.

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.

Volcano Types

Stratovolcano
Pyroclastic cone(s)
Lava dome(s)

Tectonic Setting

Rift zone
Oceanic crust (< 15 km)

Rock Types

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

Population

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

Affiliated Databases

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).
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.