Cleft Segment

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 44.83°N
  • 130.3°W

  • -2140 m
    -7019 ft

  • 331030
  • Latitude
  • Longitude

  • Summit

  • Volcano

There are no activity reports for Cleft Segment.

 Available Weekly Reports

There are no Weekly Reports available for Cleft Segment.

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1986 Aug (?) Unknown Confirmed 0 Historical Observations N Cleft Segment, S Juan de Fuca Ridge
1982 (in or before) Unknown Confirmed 0 Historical Observations N Cleft Segment, S Juan de Fuca Ridge
0270 BCE (?) Unknown Confirmed 0 Uranium-series S Cleft Segment, S Juan de Fuca Ridge

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. 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. Additional discussion of data sources can be found under Volcano Data Criteria.

Baker E T, 1991. Megaplumes. Oceanus, 34: 84-91.

Carbotte S M, Detrick R S, Harding A, Canales J P, Babcock J, Kent G, Van Ark E, Nedimovic M, Diebold J, 2006. Rift topography linked to magmatism at the intermediate spreading Juan de Fuca Ridge. Geology, 34: 299-212.

Chadwick W W Jr, Embley R W, 1994. Lava flows from a mid-1980s submarine eruption on the Cleft segment, Juan de Fuca Ridge. J Geophys Res, 99: 4761-4776.

Chadwick W W Jr, Embley R W, Fox C G, 1991. Evidence for volcanic eruption on the southern Juan de Fuca ridge between 1981 and 1987. Nature, 350: 416-418.

Embley R W, Chadwick W W Jr, Perfit M R, Baker E T, 1991. Geology of the northern Cleft Segment, Juan de Fuca Ridge: recent lava flows, sea-floor spreading, and the formation of megplumes. Geology, 19: 771-775.

Goldstein S J, Murrell M T, Janecky D R, Delaney J R, Clague D A, 1992. Geochronology and petrogenesis of MORB from the Juan de Fuca and Gorda ridges by 238U-230Th disequilibrium. Earth Planet Sci Lett, 109: 255-272.

Koski R A, Jonasson I R, Kadko D C, Smith V K, Wong F L, 1994. Compositions, growth mechanisms, and temporal relations of hydrothermal sulfide-sulfate-silica chimneys at the northern Cleft Segment, Juan de Fuca Ridge. J Geophys Res, 99: 4813-4832.

Perfit M R, Chadwick W W Jr, 1998. Magmatism at Mid-Ocean ridges: constraints from volcanological and geochemical investigations. In: Buck W R, Delaney P T, Karson J A, Lagabrielle Y (eds) Faulting and Magmatism at Mid-Ocean Ridges {Amer Geophys Union Geophys Monograph} 106: 59-115.

Smith M C, Perfit M R, Jonasson I R, 1994. Petrology and geochemistry of basalts from the southern Juan de Fuca: controls on the spatial and temporal evolution of mid-ocean ridge basalt. J Geophys Res, 99: 4787-4812.

Volpe A M, Goldstein S J, 1993. 236Ra-230Th disequilibrium in axial and off-axis mid-oecan ridge basalts. Geochim Cosmochim Acta, 57: 1233-1241.

The Cleft Segment, the southernmost of the Juan de Fuca Ridge, lies immediately north of the Blanco Fracture Zone. The 80-km-long segment is named for a nearly continuous 10-km-long, 30-50 m wide cleft at its southern end. Two episodes of sea-floor spreading have been documented along the northern part of the Cleft Segment in the 1980's. Bathymetric surveys indicated that a series of discontinuous pillow-lava mounds were extruded along a 17-km-long fissure between 1981 and 1987. The eruption possibly took place at the time of emission of a large plume of hot mineral-laden water in 1986. The location is at a depth of about 2300 m near the northern edge of the Cleft segment and the southern end of the Vance segment of the Juan de Fuca Ridge, about 500 km west of the central Oregon coast. Youthful sheet-lava flows immediately south of the pillow lavas were estimated to be only a few years older.