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Volcano's Deadly Warning

Anatomy of a Volcano

 

Intro | Ash | Lava flow | Lava dome | Lava | Vent | Tephra | Caldera | Lahar | Fissure |  Dike  | Magma

Volcano's Deadly Warning homepage

Dike
Diagram of a volcano

Dike
Dikes are tabular or sheet-like bodies of magma that cut through and across the layering of adjacent rocks and then solidify. They form when magma rises into a fracture or creates a new crack by forcing its way through rock. Hundreds of dikes can invade the cone and inner core of a volcano, often along zones of structural weakness.

Left: An exposed dike, approximately five feet wide, at the caldera of Mauna Loa Volcano in Hawaii.

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NOVA Home Find out what's coming up on air Listing of previous NOVA Web sites NOVA's history Subscribe to the NOVA bulletin Lesson plans and more for teachers NOVA RSS feeds Tell us what you think Program transcripts Buy NOVA videos or DVDs Watch NOVA programs online Answers to frequently asked questions