Module 11B: Geologic Hazards - Volcanic Hazards

• Mayon Volcano Eruption - Effusive lava flow; Ash plumes; tephra fall; volcanic gasses.
• Taal Volcano Eruption - Explosive lava flow and ash column
• effusive lava - flows slowly (easy to run from) but destroy everything in its path
• Explosive lava - falls as solid rocks
• Tephra flow hazards - most widespread volcanic hazard and it involves fragments of volcanic rock and lava blasted into the air by explosions with volcanic ash which may travel thousands of kilometers
• Pyroclastic flow - high density currents (pumice, ash, blocks, volcanic gas)
• Pyroclastic surge - like pyroclastic flow but with lower density
• Base surge - "ring-shaped” & moves radially outward
• Lahar Hazards - hot or cold mixture of rock fragments and water, due to rainfall and may cause partial or complete burial & severe flooding
• Volcanic Gasses Hazards - Can cause irritation on skin, tissues, eyes, nose, throat, and lungs.

  SO2, H2S, CO2, HF, HCl, HBr
• Why is the Philippines prone to volcanic activity?

  Pacific ring of fire

  subduction zones - Philippine sea plate subducts beneath Eurasian plate
• Magmatic Arcs and Island Chains - Accumulation of volcanic material and metamorphic processes form these land forms