1. Lava flow
Lahar
Volcanic Hazards
Landslides
Ash fall
Pyroclastic flow

2. Volcanic Hazards

3. 1.

4. 1. Eruption Column
The vertical pillar of tephra and gases rising directly above a vent.
Mt. Pinatubo, Mt. Karymsky in Russia

5. Volume of Ejected Debris
Ash

6. 2.

7. 2. Debris Avalanche (Landslide)
Gravitational force “pulls” unstable material down slope
Fills canyons and valleys with debris

8. Landslides
Monserat, Lesser Antilles, Las Colimas, El Salvador

9. 3.

10. 3. Pyroclastic Flow
Contain a high-density mix of hot lava blocks, pumice, ash and volcanic gas.
Destroys everything in its path.
Mt. Pinatubo, Philippines, 1991
Fuego volcano in Guatemala
May reach 100 miles per hour

11. 4.

12. 4. Fumaroles
Vents from which volcanic gas escapes into the atmosphere.
Fumaroles may occur along tiny cracks or long fissures.
Fumarole on Kīlauea Volcano, Hawaiʻi. Elemental sulfur vapor escaping from the fumarole has cooled to form yellow-colored crystals around its margins.

13. 5.

14. 5. Lava Bomb
Ejected magma that solidifies in mid-air and falls back to Earth as solid rock.

15. 6.

16. 6. Lava Dome
Formed by viscous magma being erupted effusively onto the surface and then piling up around the vent.

17. 7.

18. 7. Lava Dome Collapse
When the lava dome is too steep & it collapses due to gravitational force.
Sinabung, Sumatra
Monserrat

19. 8.

20. 8. Lahars (Mud or debris flow)
Hot or cold mixture of water and rock fragments that flows down the slopes of a volcano.
Need water source

21. 9.

22. 9. Acid Rain
Rainfall containing elevated levels of strong acids, due to carbon emissions.
Iceland

23. 10.

24. 10. Tephra (Ash) fall
Fragments of microscopic rock ejected into the air by an erupting volcano.
Clogs machinery, covers vegetation, irritates lungs and eyes
Photomicrograph of ash from the Mt. Tehama eruption (Lassen Peak)
Ash deposited associated with the eruption of the Long Valley Caldera

25. 11.

26. 11. Eruption Cloud
A cloud of tephra and gases that forms downwind of an erupting volcano.
Can drift for 1000s of kilometers
Guagua Pichincha, Ecuador.
Eruption cloud from Guagua Pichincha Volcano 10 km west of Quito,

27. Understanding Volcanic Hazards
Past history
How often
Types of hazards
Extent of hazards
Location of past events
Ash deposits associated with the eruption of Santorini, Greece