Olkaria

Photo of this volcano
Google Earth icon
  Google Earth Placemark
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 0.904°S
  • 36.292°E

  • 2434 m
    7984 ft

  • 222090
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Olkaria.

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

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

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude
222090

1770 CE

2434 m / 7984 ft

0.904°S
36.292°E

Volcano Types

Pyroclastic cone(s)
Lava dome(s)
Caldera

Rock Types

Major
Rhyolite
Trachyte / Trachyandesite
Basalt / Picro-Basalt
Minor
Trachybasalt / Tephrite Basanite

Tectonic Setting

Rift zone
Continental crust (> 25 km)

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
59,747
59,747
208,003
8,437,829

Geological Summary

The Olkaria volcanic complex, located immediately south of Lake Naivasha and west of Longonot volcano, comprises up to 80 individual commenditic and other peralkaline rhyolitic centers. A thick, geochemically diverse basal complex is overlain by a dominantly silicic lava-dome and lava-flow complex constructed within a largely obscurred 11 x 7.5 km wide caldera that formed about 20,000 years ago following the eruption of welded pantelleritic ignimbrites. The youngest known eruption originated from the Ololbutot fissue on the SW side of the complex and produced a 5 cu km lava flow and a pumice flow that has a radiocarbon age of about 180 years. Fumarolic activity occurring at the Njorowa Gorge and at the Orengingnai and Olkaria (Orgaria) pumice cones, and Olkaria is the site of a large 50-80 sq km high-temperature geothermal field.

References

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

Heumann A, Davies G R, 2002. U-Th disequilibrium and Rb-Sr age constraints on the magmatic evolution of peralkaline rhyolites from Kenya. J Petr, 43: 557-577.

Karingithi C W, Arnorsson S, Gronvold K, 2010. Processes controlling aquifer fluid compositions in the Olkaria geothermal system, Kenya . J Volc Geotherm Res, 196: 57-76.

Marshall A S, Hinton R W, Macdonald R, 1998. Phenocryst flourite in peralkaline rhyolites, Olkaria, Kenya Rift Valley. Mineral Mag, 62: 477-486.

Marshall A S, Macdonald R, Rogers N W, Fitton J G, Tindle A G, Nejbert K, Hinton R W, 2009. Fractionation of peralkaline silicic magmas: the Greater Olkaria volcanic complex, Kenya Rift Valley. J Petr, 50: 323-359.

Richard J J, Neumann van Padang M, 1957. Africa and the Red Sea. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI 4: 1-118.

Smith M, 1991. (pers. comm.).

Thompson A O, Dodson R G, 1963. Geology of the Naivasha area. Geol Surv Kenya Rpt, 55: 1-80.

Eruptive History


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


Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1770 ± 50 years Unknown Confirmed   Radiocarbon (uncorrected) Ololbutot
4050 BCE (?) Unknown Confirmed   Tephrochronology
6050 BCE (?) Unknown Confirmed   Tephrochronology NE side (Gorge Farm)

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

Olenguruoni | Hobley Volcano

Cones

Feature Name Feature Type Elevation Latitude Longitude
Olkaria Hill
    Olgaria
Pyroclastic cone
Orengingnai Pyroclastic cone

Craters

Feature Name Feature Type Elevation Latitude Longitude
Ololbutot Fissure vent

Domes

Feature Name Feature Type Elevation Latitude Longitude
Broad Acres Dome
Gorge Farm Dome
Kibikoni Dome
Ndabibi Dome
Olenguruoni Dome
Oserian Dome
Plateau Dome

Photo Gallery


Volcanic vents of the northern part of the Olkaria volcanic complex are visible immediately south of Lake Naivasha (upper right). The complex comprises up to 80 individual commenditic and other peralkaline rhyolitic centers, many of which are visible in this Landsat image. The youngest known eruption has a radiocarbon age of about 180 years. Fumarolic activity occurs at the Njorowa Gorge and at the Orengingnai and Orkaria (Olgaria) pumice cones.

NASA Landsat image, 1999 (courtesy of Hawaii Synergy Project, Univ. of Hawaii Institute of Geophysics & Planetology).

Smithsonian Sample Collections Database


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

Affiliated Sites

Large Eruptions of Olkaria 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.