Anatomy of Nyiragongo

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 fissure or creates a new crack by forcing its way through rock. Hundreds of dikes can invade the cone and inner core of a volcano, as they do in Nyiragongo, often along zones of structural weakness.