Volcanic Hazards Flashcards
What is volcanic magnitude?
Numerical index of how explosive a volcano is.
The VEI treats what four things as the same? What does it not quantify?
Tephra, lava, blocks, ash.
Sulfur-content.
Describe Hawaiian eruptions. Describe the viscosity and magma composition.
Effusive, lava flows from vent gently.
Low viscosity, basaltic.
What are Strombolian eruptions? Describe the viscosity and where these eruptions place on the VEI.
Relatively small eruptions of cinders, lapilli, lava bombs.
More viscous than Hawaiian.
VEI 1-3.
What are Vulcanian eruptions and what is their composition? How do they begin?
Dense clouds of ash. Andesitic to rhyolitic in composition.
Phreatic explosion.
“Explosions like cannon fire at irregular intervals” refers to what kind of eruption?
Vulcanian.
What are Plinian eruptions? Where do they fit on the VEI scale? From which volcano is its description based?
Columns of volcanic debris, gases, large amounts of pumice.
VEI 4-6.
Vesuvius.
How many earthquakes occur at Yellowstone each year? What is the lava composition?
1500-2500.
Basalt and rhyolite.
There are seven methods from which we can monitor volcanoes. What are they?
Seismicity: detect and locate earthquakes which may indicate magma movement.
Deformation.
Acoustic flow monitoring: detect ground vibration at frequencies in river valleys subject to lahars.
Hydrothermal water chemistry: monitoring changes in temperature and chemistry of groundwater offers information in volcanic changes.
Volcanic gases.
Thermal imaging.
Digital elevation maps.
What are three volcanic benefits?
Volcanic soils.
Geothermal power.
Creation of new land.
What are four other hazards that can be associated with volcanoes?
Earthquakes.
Fire.
Landslides.
Tsunami.
