Introduction to Volcano Hazards Flashcards
(22 cards)
[ Identification ]
It is an opening or vent on the earth’s surface when molten rocks, gases, and ashes are ejected.
Volcano
[ True or False ]
Volcanoes are generally conical in shape.
True
[ What are these? ]
- Its activity
- Its composition and structure
- Its eruption
Classifications of Volcano
[ Identification: Classifications of Volcano ]
- Active Volcano
- Erupting Volcano
- Dormant Volcano
- Extinct Volcano
Classified by ACTIVITY
[ Identification: Classifications of Volcano (By ACTIVITY) ]
Has at least an eruption within the last 10,000 years.
E.g., Taal Volcano
Active Volcano
[ Identification: Classifications of Volcano (By ACTIVITY) ]
As active volcano erupts, distinguished as either explosive or quiet.
Erupting Volcano
[ Identification: Classifications of Volcano (By ACTIVITY) ]
Has not erupted within the last 10,000 years. It is not certain when this kind of volcano will erupt but is expected to occur in the future.
E.g., Mount St. Helens
Dormant Volcano
[ Identification: Classifications of Volcano (By ACTIVITY) ]
Has not had an eruption within historic times and is not expected to erupt again in a comparable time scale in the future.
E.g., Kuhala in Big Island, Hawaii
Extinct Volcano
[ Identification: Classifications of Volcano ]
- Shield Volcano
- Cinder Cone
- Stratovolcano
Classified by COMPOSITION AND STRUCTURE
[ Identification: Classifications of Volcano (By COMPOSITION & STRUCTURE) ]
It is generally low and dome shape.
These are mountains that have been slowly shaped by lava flows, with diameter of 4.8 to 6.4 km and height of about 1,200 - 1,500 feet.
E.g., Mauna Loa
Shield Volcano
[ Identification: Classifications of Volcano (By COMPOSITION & STRUCTURE) ]
The result of eruption from a single vent.
Typically viewed as hardened lava, which piled up around the vent and then formed a mountain. They are generally about 300 - 1,200 feet.
E.g., Smith Volcano
Cinder Cone
[ Identification: Classifications of Volcano (By COMPOSITION & STRUCTURE) ]
Also known as Composite Volcano.
Formed by alternating layers of lava and pyroclastic materials from multiple eruptions that occurred through time. They can rise up to 8,000 feet.
E.g., Mayon Volcano
Stratovolcano
[ Identification: Classifications of Volcano ]
- Explosive Eruption
- Quiet
Classified by ERUPTIONS
[ Identification: Classifications of Volcano (By ERUPTIONS) ]
Happens due to the building of thick magma with high silica content.
It is slow flowing and very viscous.\
This eruption is rapid and very violent.
It spews lava, ash, and other volcanic material over large distances.
Explosive Eruption
[ Identification: Classifications of Volcano (By ERUPTIONS) ]
Also known as fissure eruption.
Emits a lot of lava coming from a fissure or crack in the surface. Lava derived from magma with low silica content has a low viscosity allowing gas to escape.
Quiet
[ What are these? ]
- Lahar
- Ash Fall
- Pyroclastic Flow
- Ballistic Projectile
- Volcanic Gases
- Lava Flow
Volcano Hazards
[ Identification: Volcano Hazards ]
A mudflow composed of rocky debris, water, and pyroclastic materials.
Lahar
[ Identification: (Part of) Volcano Hazards ]
Also known as tephra
Hard, extremely abrasive, mildly corrosive, conducts electricity when wet, and does not dissolve in water.
Volcanic Ash
[ Identification: Volcano Hazards ]
High-density mixtures of hot, dry rock fragments and hot gases that move away from the vent that erupted them at a high speed.
Basal flow-turbulent cloud of ash known to exhibit high temperature.
Pyroclastic Flow
[ Identification: Volcano Hazards ]
Basically rocks that an erupting volcano sends into the air.
Ballistic Projectile
[ Identification: Volcano Hazards ]
- Carbon monoxide
- Carbon dioxide
- Sulfur dioxide
- Hydrogen sulfide
- Hydrogen chloride
- Hydrogen fluorine
- Helium
Volcanic Gases
[ Identification: Volcano Hazards ]
A stream of molten rock that flows out of volcano or volcanic vent.
Can be very fluid or very sticky, depending on its composition and temperature.
Lava Flow
