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Seastack, Central California
Sea stack along Oregon’s northwest coast. Image from USGS Center for Coastal Geology.

Sea Stack

spacer image Sea stacks are blocks of erosion-resistant rock isolated from the land by sea. Sea stacks begin as part of a headland or sea cliff. Relentless pounding by waves erodes the softer, weaker parts of a rock first, leaving harder, more resistant rock behind.
spacer image Click here to see Jump-off Joe, a sea stack, erode over 100 years.
| Return to Where Parks Meet the Sea index |

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This site is a cooperative project of the
US Geological Survey Western Earth Surface Processes Team
and the National Park Service.

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This page was last updated on 9/10/99