Volcanoes, Atmosphere, and Mass-Wasting Flashcards
What is the VEI scale based on?
- Volume of magma erupted
- Volume of erupted material
- Eruption column height
- Eruption type
- Climate response
Describe Basalt
- Mafic Extrusive Rock
- Dark in color
- Low-viscosity lava (flowy)
- Icelandic, Hawaiian, Strombolian
- Shield and Cinder Cones
Describe Rhyolite
- Felsic Extrusive Rock
- Light in color
- High Viscosity lava (sticky)
- Explosive & Pyroclastic Flows
- Pelean and Plinian
- Stratovolcanoes/Composite Domes
Describe Andesite
- Intermediate Extrusive Rock
- Medium in color (grey)
- Medium Viscosity lava
- Stratovolcanoes/Composite Domes
- Strombolian and Vulcanian
Describe Gabbro
- Mafic Intrusive Rock
- Low-viscosity magma (flowy)
- Icelandic, Hawaiian, Strombolian
- Shield and Cinder Cones
Describe Granite
- Felsic Intrusive Rock
- High Viscosity magma (sticky)
- Explosive & Pyroclastic Flows
- Pelean and Plinian
- Stratovolcanoes/Composite Domes
Describe Diorite
- Intermediate Intrusive Rock
- Medium Viscosity magma
- Stratovolcanoes/Composite Domes
- Strombolian and Vulcanian
What is a Pluton?
What is a Batholith?
What is the Sierra Mountains Batholith made of?
- Any type of intrusive rock body
- The largest type of pluton
- Granite
Define Aphantic, Porphyritic, and Vesicular
- Fine-grained extrusive rocks
- Phaneretic minerals within an aphantic land mass
- extrusive rocks that are filled with bubbles
Rank pyroclast from largest to smallest.
Bombs, Lapilli, Ash, Tuff
What is the most common type of igneous rock?
Basalt
What volcanoes are associated with VEI 1 eruptions?
Shield Volcanoes
What volcanoes are associated with VEI 2 eruptions?
Cinder Cones
What volcanoes are associated with VEI 3-4 eruptions?
Stratovolcanoes/Composite Dome volcanoes
What volcanoes are associated with VEI 4-6 eruptions?
Stratovolcanoes/Composite Dome volcanoes + pyroclastic flows
What volcanoes are associated with VEI 7-8 eruptions?
Calderas
What is Pahoehoe lava flow? What is an A’a lava flow?
P: Ropey surface
A: craggy surface
What is a lahar
- Volcanic mudflow
- ash and water mix
- flows quickly
What volcano is closest to SSU?
Konocti
Eyjafjallajoekull (2010) eruption
Hint: air traffic
- Covered by an ice-cap glacier
- Divergent boundary and Hotspot
- Canceled air traffic
Long Valley Caldera (USA)
Hint: bowen’s
Last eruption 760,000 ybp
Basaltic to rhyolitic
Pyroclastic clouds & flows
currently a resurgent dome
Crater Lake, Mount Mazama
Hint: Wizard
Rhyodacite magma
erupted in 5677 BCE
Wizard Island
Pyroclastic flow 1.25 km wide
Mount St. Helens 1980
Hint: landslide
Dacite eruption that killed 35 people
Height decreased by 1300ft
500 kph pyroclastic flows
172 earthquakes > M2.6 in 2 days
Largest landslide
What volcanoes are a part of the Cascades?
Mt. Rainer, Mount St. Helens, Mt. Mazama, Mt. Shasta, Mt. Lassen
1912 Novarupta
Hint: smokes
The largest eruption of the 1900s
VEI 6 eruption Alaska
Pyroclastic ash flows made the Valley of 10,000 Smokes - a layer of tuff still cooling
Mt Rainer 1895
Hint: McKenna
Lahar hazard to Seatle & Tacoma
Erupted 16 times between 1820-1892
Mt. Unzen 1991
Hint: Kraffts
Felsic + pyroclastic flows
Killed 43 people including the Kraffts
1792-lava dome collapsed creating a tsunami that killed 15,000 people (worst volcanic disaster in Japan history
Nevado del Ruiz 1985
Hint: lava domes
Colombia in the Andes
5 lava domes
Plinian eruptions
Dangerous lahars due to summit glaciers
23,000 buried in Armero
Mount Pelee 1902
Hint: deadly
Deadliest eruption of the 1900s
Martinique (Caribbean)
30,000 killed by pyroclastic flows
Thera, Santorini (~1600BCE)
Hint: Nile River
Destroyed the Minoan civilization of Greece
VEI 6 eruption
Killed 40,000
6km caldera that produced 200km deep ash layer of tuff
turned the Nile river red (biblical thing)
Mount Vesuvius 76 CE
Hint: Pompeii
First observations of Plinian eruptions by Pliny the Younger (hence Plinian)
Buried Pompeii and Herculaneum in pyroclastic flows
Has erupted 50 times since
Mount Etna 2011
Hint: tsunami
Low-viscosity lava flows (Very flowy) with intermittent caldera collapse
Sicily, Italy
Debris avalanches and pyroclastic flows happen intermittently which caused a tsunami
Mount Pinatubo 1991
Hint: death toll
The death toll was relatively low (800) because the Philippine government listened to the Kraffts and made evacuation plans
Pyroclastic flows, ash, and lahars
VEI 6 erupted Andesite and Dacite
Global temp dropped 0.5 C
Coincided with a Typhoon Yunya
What volcano erupted in 1257 AD? What were its global effects?
Mount Samalas in Indonesia, the top collapsed which caused a catastrophic eruption that blasted 27 miles high
This caused a volcanic winter, which in turn caused a famine that killed 50,000 people
Mount Merapi
Most dangerous volcano in Indonesia
What is insolation? What are the 3 types of wavelengths that come from insolation and their percentages?
incoming solar radiation that reaches Earth as a broad spectrum of wavelengths
~43% is visible, ~49% is near-infrared, and ~7% is UV
What range can humans see?
The visible light spectrum (colors)
What is Albedo?
The reflectivity of the Earth’s surface.
30% of the radiation from the sun is reflected back to the atmosphere
What types of radiation does the Earth absorb?
What types of radiation does the Earth emit?
The Earth absorbs short-wave radiation
The Earth emits long-wave radiation
What are greenhouse gases and how do they work? What is their impact on the Earth?
The most common ones are CO2, H2O, O3, NO2, and CH4
They absorb the long-wave radiation in the atmosphere and cause global warming
What is the atmosphere?
An envelope of gases gravitationally attracted to the Earth
A heat engine that uses solar radiation to produce wind
Helps air circulate to create weather
What are the layers of the atmosphere starting from the closest to the Earth’s surface to the furthest? Describe each layer.
Troposphere - Where weather and life reside
Stratosphere - Layered, planes fly through here, horizontal wind
Mesosphere - Middle, stops meteoroids
Thermosphere - Hot
Exosphere - air escapes
What is the ozone layer?
a layer in the earth’s stratosphere containing a high concentration of ozone, which absorbs most of the ultraviolet radiation reaching the earth from the sun.
Laki 1873
Hint: Dangerous Gases
Iceland VEI6 Basaltic lava flows
Fissure eruptions over 8 months
High levels of hydrofluoric acid & sulfuric acid killed 50% of livestock and 25% of pop
Poisonous gases caused crop failures in Europe, droughts in India, and famine in Japan
68-60Ma Deccan Traps in India
Contributed to the extinction of the dinosaurs
Thickness > 6,500ft
Area: 500,000km^2
Volume: 512,000km^3
Global temp dropped 20 degrees C
250Ma Siberian traps in Siberia
Contributed to the Great Dying (just before dinos)
Thickness: 3.5 km
Area: ~7 million km^2
Volume: ~4 million km^3
Equatorial Ocean temp > 40 degrees C
Explosive eruptions of rhyolite + carbon
1452 Kuwae in Vanuatu
Hint: Little Ice Age
Caldera collapse
Initiated Little Ice Age: sulfate spike in antarctic& Greenland ice cores
Sweden had a total wheat crop failure
Constantinople fell to the Turks in 1453
Ming Dynasty in China suffered a volcanic winter
Tens of thousands dead
1600 Huaynaputna in Peru
Hint: Winds
VEI 6
1500 directly; 2mil worldwide
Russia: famine that killed up to 2 mil that caused the Tsar to be overthrown
Germany: wine harvest was 5% of normal
Swiss, Sweden, Estonia, Latvia: coldest winter on record
Pacific record sailing times due to high winds
1815 Tambora
Hint: Temperature
VEI 7
Killed 10,000 from the blast + 80,000 from famine and disease
Caused 1816 “Year Without a Summer”
Global average temp dropped 5 degrees C
1883 Krakatoa
Hint: Sound
VEI 6 intermediate eruption
15 mi high ash cloud that darkened the sky for 275 mi
Loudest sound in recorded history
global atmospheric shockwaves
global average temp 1.2 degrees C cooler for 5 yrs
List some Calderas
Yellowstone, Long Valley, Toba, Taupo
What primary disasters can cause mass wasting as a secondary disaster?
Droughts
Heat Waves
Winter Storms
Tropical Cyclones
Flooding
Wildfires
Local Storms
Volcanic Eruptions
Earthquakes
Is there a minimum angle required for a mass-wasting event to happen?
No, but the steeper the slope, the less stable it is.
What are the two important factors in the stability of land?
Water: added water decreases friction and adds weight
Oversteepening of slopes creates instability
Where do mass movements occur?
Places where there are:
- excessive precipitation
- weak rock or soil
- undercutting
- flowing water
- steep terrain
How can earthquakes cause mass wasting?
Shaking destabilizes slopes
Liquefaction causes soil and sediment to flow
How can wildfires cause mass wasting?
Burning vegetation that keeps slopes stable
What are the 3 classification processes of mass wasting?
Type of material, type of motion, and the velocity of the movement
What types of materials fall under mass wasting?
Mud, Ash, Snow, Earth, Rock
Describe Fall (mass wasting movement type)
Free-falling pieces
Describe Slide (mass wasting movement type)
material that moves along a surface as a coherent mass.
Slump: movement of mass as a unit along a curved surface over steepened slopes
Block slide: fractured landslides
Rotational: most common
Submarine: occurs on volcanic flanks, continental slopes, & near active deltas
Describe Flow (mass wasting movement type)
wet:
mudflows/lahars, debris flow, solifluction (tundra only)
dry:
debris avalanche (snow & rock), grain flow, earthflow (humid regions), creep (expansion and contraction)
What are the largest mass-wasting events on Earth?
Volcanic Debris Avalanches
Frank, Canada Landslide 1903
4:10 am
tons of limestone 1,300 ft high and 4,000 ft wide came down and buried a portion of Frank
killed 66 people
caused by unsafe mining techniques
Winter of Terror 1951
649 avalanches in the Swiss Alps
Killed 265 people
~1000 structures destroyed
1999 Vargas Tragedy
Hint: 20%
Venezuela
Killed 20% of the pop (10,000)
Caused by 40 in of rain falling within a few days
mudflows & landslides created alluvial fans
A similar event occurred in 1951
1963 Vajont disaster
Hint: Dam
Italy
Lost 1901 people
A landslide fell into the water behind a dam creating a tsunami
They built the dam knowing the risk
Why is San Francisco Bay Area so prone to landslides?
Volcanic history
Active fault lines
Climate
Storms and floods
Droughts
Wildfires
Oso, Washington landslide 2014
hint: rainfall
A major landslide occurred 4 miles east of Oso, Washington, United States, on March 22, 2014, at 10:37 a.m. local time.
deaths: 43
Cause: soil saturation from heavy rainfall
