Skip to content
LITHOEN

Tectonic plate

Somali Plate

The eastern part of what is often mapped as a single African Plate, separated from it in plate models by the East African Rift. Whether the rift has yet made two plates is a question about how much relative motion a model needs before it draws a boundary.

World map showing twenty-four plate outlines as thin dark lines over a pale coastline, with heavier red plate-boundary curves over them, subduction segments dashed, and thirteen hatched purple regions marking zones of distributed deformation.
Twenty-four tectonic plates as outlined in model PB2002 (Bird, 2003), with the boundary curves Lithoen holds for them and the thirteen regions the model calls orogens. Every line here is a model boundary rather than a mapped geological contact: the model is a compilation from published sources at varying scales, its author states that accuracy never equals precision, and boundary class changes along a boundary — so only the segments the source labels subduction are shown as such. Outlines are generalised for display at a recorded tolerance. Areas near the poles are severely exaggerated by the projection, which is stated on the figure.

Figure by Lithoen. Plate model PB2002 from Bird (2003), doi:10.1029/2001GC000252; GIS conversion by Hugo Ahlenius, Nordpil, ODC-By 1.0. Made with Natural Earth. Underlying data remain under their own licences. · LITHOEN-ORIGINAL · Derivative: Generated from published Lithoen spatial records by scripts/generate-maps.ts; no coordinate was edited by hand. Features spanning ±180° are split for rendering only; the stored geometry is unchanged.

Classification

plate class
major

How this is mapped

One published representation of where Somali Plate is. Each is one interpretation, by one identified source, at one scale — not the shape of the thing itself.

  • Tectonic model geometry

    Polygon · 265 positionspreferred for publication

    Geometry that exists because a model defines it — a rigid-plate outline, a zone where a model declares itself inapplicable. It is a property of the model, and changes when the model is revised. It is present-day geometry from a present-day model; a palaeogeographic reconstruction is a different thing and Lithoen does not hold one.

    The Somali Plate as outlined in model PB2002 (Bird, 2003). This is the model’s boundary, not a mapped geological contact: it is where a rigid-plate model puts the edge of a plate, and Bird’s own documentation states that coordinates are given to a precision of about 60 m while "accuracy never equals precision". Where deformation is distributed rather than confined to a line, the model marks the region as an orogen and the outline there is a convenience.

    Boundary certainty
    InterpretedThe boundary was placed by a geologist reading evidence: mapping, geophysics, geochronology, structure. It is reproducible from that evidence and it is an interpretation of it. Most geological boundaries are this.
    Status of this geometry
    modelledThe status of the geometry, which need not match the status of what the entity’s claims assert.
    Dataset
    PB2002 plates, boundaries and orogens as GeoJSON (fraxen/tectonicplates)Plate model PB2002 from Bird (2003), doi:10.1029/2001GC000252; GIS conversion by Hugo Ahlenius, Nordpil, ODC-By 1.0.

    What was done to this geometry

    • By Lithoen — Douglas–Peucker, 479 positions to 265
    • By Lithoen — Coordinates rounded to 4 decimal places, about 11 m of longitude at the equator.
    • Before it reached Lithoen — Bird (2003) digitised the boundary curves from published sources at varying scales; the model is a compilation, not a single survey.
    • Before it reached Lithoen — The GIS conversion (Ahlenius, ODC-By 1.0) split segments spanning the -180/180 meridian and moved them, as its README states. Four plates therefore arrive as multi-part geometries.

In the knowledge graph

Record last updated 2026-09-07. Corrections follow the published corrections policy; superseded claims are retained, never silently edited.