Most
volcanos occur at the edge of tectonic plates, where magma can rise to the
surface. A volcano’s shape depends mainly on the viscosity of the lava, the
shape of the vent, the amount of ash, and the frequency and size of the
eruptions. In fissure through a crack, forming lava plateaux or plains. In
cone-shaped volcanoes, the more viscous the lava, the steeper the cone. Some
cones fall in on themselves or are exploded outwards, forming calderas.| Cross-section through a stratovolcano (vertical scale is exaggerated): | |
|---|---|
| 1. Large magma chamber 2. Bedrock 3. Conduit (pipe) 4. Base 5. Sill 6. Dike 7. Layers of ash emitted by the volcano 8. Flank | 9. Layers of lava emitted by the volcano 10. Throat 11. Parasitic cone 12. Lava flow 13. Vent 14. Crater 15. Ash cloud |
 |
| Conical mount Funji in japan, at sunrise from lake Kawaguchi (2005) |
 |
| Mayon, near-perfect stratovolcano in the Philipines |
 |
| Pinatubo ash plume reaching a height of 19km, 3 days before the climate eruption of 15 june 1991 |
No comments:
Post a Comment