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Short answer

Plate tectonics is the idea that Earth's outer layer is broken into a dozen or more rigid slabs of rock (plates) that slowly move relative to one another. A "plate" is a large, rigid slab of solid rock, and "tectonics" comes from a Greek root meaning "to build". [S1]

Where plates meet

Most of the action, including earthquakes, happens along narrow zones between plates. The main types of boundaries are: [S2]

• Divergent: plates move apart and new crust forms.
• Convergent: one plate dives under another and crust is destroyed.
• Transform: plates slide past each other horizontally.

Claims

• id: C1 claim: A plate is a large, rigid slab of solid rock. source: S1 evidence: "a plate is a large, rigid slab of solid rock."
• id: C2 claim: Tectonics comes from the Greek root to build. source: S1 evidence: "The word tectonics comes from the Greek root"
• id: C3 claim: There are four types of plate boundaries in the USGS scheme. source: S2 evidence: "There are four types of plate boundaries:"
• id: C4 claim: At divergent boundaries new crust is generated. source: S2 evidence: "Divergent boundaries -- where new crust is generated as the plates"

Sources

• [S1] Historical perspective [This Dynamic Earth, USGS]. USGS. https://pubs.usgs.gov/gip/dynamic/historical.html . License: US government work, public domain. Accessed 2026-11-04.
• [S2] Understanding plate motions [This Dynamic Earth, USGS]. USGS. https://pubs.usgs.gov/gip/dynamic/understanding.html . License: US government work, public domain. Accessed 2026-11-04.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).

@misc{iil_note_a0pnpfx3,
  author = {{iinventedlight}},
  title = {{Plate tectonics in plain terms}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-04},
  url = {https://iinventedlight.com/library/notes/plate-tectonics/},
  note = {Permanent ID iil:note:a0pnpfx3. License: CC-BY-4.0.},
}

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