Download Volcanic and Tectonic Landforms

Volcanic and Tectonic Landforms
Tectonic Activity
Includes:
1. Folding
– Esp. Sed Rock
Folded Limestone
Tectonic Activity
2. Faulting
– Breaking of Crust
– Esp. Ign & Met Rocks
Earthquakes
• Due to Movement Along Fault
– Releases Seismic Energy
• Ground Shakes
(The earth quakes)
Worst Earthquake Shaking?
• Hilltop or Flat Land?
Solid Rock
• Soft Sediment
& Groundwater
Tectonic Landforms: Mountains
• Raised along Fault(s)
• Sierra Nevada
Before
Now
Sierra Nevada
• Steep Eastern Slope
Tsunami
• “Tidal Wave”
• E.Quake on Sea Floor
– Shakes Water
– Like Huge Circular Ripples
– Wave Heights of…?
Volcanic Activity
• Volcano
– Cone or Dome-Shaped Mtn
– Built by Emission of:
• Lava
• Pyroclastics
–Cinders, Ash
• Gases
Volcanic Eruptions
• Depend on Magma/Lava
1. Basaltic Lava
• Fluid
• Holds Little Gas
• Frequent, Calm Eruptions
Volcanic Eruptions
2. Rhyolitic/Intermediate Lava
– Viscous
– Traps/Holds Lots of Gas
– Infrequent, Violent Eruptions
Mt. St. Helen’s
• 1980 Eruption…
Distribution of Volcanoes
• Around the _____ Ocean
• “Pacific Ring of Fire”
Types of Volcanoes
1. Stratovolcano
2. Shield
3. Cinder Cone
Stratovolcano
• Tall, Steep
• Rhyolitic or
Intermediate Lava
• Explosive
Near Mexico City
Stratovolcano
• Layered Slopes
(Strata)
– Lava Flows
– Pyroclastics
Stratovolcano
• Mt. Fuji, Japan
• Crater on Top
Damage from Stratovolcanoes
1. Hot Ash & Gas
2. Mudflows
NOT from Flowing Lava
1. Hot Ash & Gas
• Pyroclastic Flow
– Mt. Vesuvius
• Near Naples, Italy
Crater of Mt. Vesuvius
Pyroclastic Flow
• Destroyed Pompeii
Pompeii Victim
Mt. Pelée (Caribbean)
Destroyed by Pelee’s
Pyroclastic Flow
Pyroclastic Flow (pg. 191)
2. Volcanic Mudflows (Lahars) (pg. 174)
• “Lahar” (Indonesian word)
• Fresh Ash Mixes With:
– Heavy Rain
• Tropical Volcanoes
– Melted Snow
• Mid-Lat Volcanoes
Lahar in Colombia (pg. 180)
Caldera (p. 173)
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Large Depression Atop Volcano
Formed after Huge Eruption
Top Collapses Downward
Crater Lake, Oregon (p. 176)
Crater Lake, Oregon
• Should be called “___________ Lake”
Shield Volcano
• Oceanic Volcanoes
– Hawaii
– Type of Lava?
• Basaltic
• Fluid
Shield Volcanoes
• Gentle Slopes
• Flat On Top
• Mauna Loa, Hawaii
“Long Mtn”
Hawaiian Islands
• Not on Plate Boundaries
• Why Volcanic?
Hot Spot Under Hawaii
• Heat From Mantle
• Produces Basaltic Lava
– Seafloor Volcano
– Builds up to form Vol. Island
Hot Spot Under Hawaii
• Pacific Plate Moves Over Hot Spot
– 1st Vol is Moved Away
• Becomes an Extinct Vol
– New Vol Forms over Hot Spot
Hot Spot Under Hawaii
Hawaii – Big Island (pg. 178)
• Current Volcanic Activity
• Gentle Slopes, Little Erosion
Kauai – Old, Eroded Volcano
Kauai
Cinder Cones (pg. 173)
• Slopes 100% Pyroclastics
– No Lava Flow from Crater
1. Small, Fountain Eruptions
– Fluid, Basaltic Lava
2. Lava Flows from Base
Cinder Cones
• Under 1500’ Tall
Cinder Cones & Lava Flow