DRRR 1ST QUARTER EXAM

It is an opening in the Earth’s crust that allows molten rock, gases, and debris to escape to the surface.

• mountain

• Hills

• Volcano

Refers to surface changes on a volcano, such as subsidence (sinking), tilting, or bulge formation, due to the movement of magma below the surface.

• lahar

• seismic activity

• ground deformation

Smell of sulfur (rotten eggs)

• Olfactory

• Auditory observations

• Feel (Tactile)

Are stream-like flows of incandescent molten rock erupted from a crater or fissure.

• lava flows

• Pyroclastic flows

• Ashfall or tephra fall

Are showers of airborne fine- to coarse-grained volcanic particles that fallout from the plumes of a volcanic eruption.

• lava flows

• Pyroclastic flows

• Ashfall or tephra fall

Are turbulent masses of ejected fragmented volcanic materials (ash and rocks), mixed with hot gasses (200°C to 700°C to as hot as 900°C) that flow downslope at very high speeds (>60kph).

• lava flows

• Pyroclastic flows

• Ashfall or tephra fall

Are rapidly flowing thick mixture of volcanic sediments (from the pyroclastic materials) and water, usually triggered by intense rainfall during typhoons, monsoons, and thunderstorms.

• lahars

• Pyroclastic flows

• Ashfall or tephra fall

Are volcanic materials directly ejected from the volcano’s vent with force and trajectory.

• lahars

• Ballistic projectiles

• Ashfall or tephra fall

Are gasses and aerosols released into the atmosphere, which include water vapor, hydrogen sulfide, sulfur dioxide, carbon monoxide, hydrogen chloride, hydrogen fluoride.

• lahars

• Volcanic gasses

• Pyroclastic flows

Massive collapse of a volcano, usually triggered by an earthquake or volcanic eruption

• Debris avalanche

• Volcanic gasses

• Pyroclastic flows