Volcanoes

4 types of lava Lava is based on how it moves out and away from the volcano. Lava is based on how it moves out and away from the volcano. –Blocky lava: Cool and stiff, it does not travel far from the volcano. It usually oozes out after an explosive eruption. –Pahoehoe (pah HOY HOY): slow flowing like wax dripping from a candle. It has a rope-like appearance.

4 types of lava –Aa (AH ah): This lava has a jagged surface and pours out of a volcano much quicker. It is brittle and hardens quickly, allowing for molten rock to flow underneath. It is named after the sound you would make if you walked across it barefoot. –Pillow lava: The result of lava erupting underwater. The water causes rapid cooling and results in bubble like pillows.

Can you identify these lavas?

Explosive lava If it doesn’t flow out of the volcano, it gets blasted from the volcano. These blasted pieces can range in size. Pyroclastic material (or pieces shot from the volcano) are classified by their sizes. If it doesn’t flow out of the volcano, it gets blasted from the volcano. These blasted pieces can range in size. Pyroclastic material (or pieces shot from the volcano) are classified by their sizes.

Types of pyroclastics There are 4 main types/sizes ejected from explosive eruptions: There are 4 main types/sizes ejected from explosive eruptions: –Volcanic blocks: Solid chunks of rock blasted from the volcano, they are basically chunks of the volcano top. –Volcanic bombs: Large blobs of magma that harden in the air. They often form tear-drop shapes as they fly through the air. They are larger than 64mm in diameter.

Types of pyroclastics –Cinders (or Lapilli (La pillee): Meaning “little stones” in Italian), these are pebble-like pieces that range from 2mm to 64mm. –Volcanic Ash: Particles that are less than 2mm in diameter. Ash forms when gases force magma to explode into tiny pieces.

Can you identify these pyroclastics?

Types of Volcanoes Shield Volcano Shield Volcano –Layers of lava from repeated non-explosive eruptions. –Wide with a gentle slope. –Often the tallest because it is always increasing in size, never decreasing.

Types of Volcanoes Cinder cone volcano Cinder cone volcano –Small volcanic cones made from its own pyroclastic material. –Has a steeper slope with a narrower base. –They often erode quickly because they are not cemented down by lava.

Types of Volcanoes Composite Volcano (Stratovolcano) –T–T–T–The most common type of volcano. –T–T–T–They form by explosive eruptions followed by lava flows. –A–A–A–Alternating layers of lava and pyroclastics form broad bases with steep sides.

Famous Volcanoes Here is a list of famous volcanic eruptions in history Here is a list of famous volcanic eruptions in history

Mt. Vesuvius Perhaps the most famous Perhaps the most famous It completely buried the City of Pompeii in 79 A.D It completely buried the City of Pompeii in 79 A.D Town was covered in 20 feet of ash Town was covered in 20 feet of ash Unknown died Unknown died

Mount Pelee Erupted in 1902 Erupted in 1902 Destroyed the Town of St. Pierre Destroyed the Town of St. Pierre Killed over 30,000 (only 2 survived in the whole city) Killed over 30,000 (only 2 survived in the whole city) Only took 2 minutes to destroy the whole city Only took 2 minutes to destroy the whole city

Before

After

Krakatau Largest explosion in recorded history (heard 4000 miles away!) Largest explosion in recorded history (heard 4000 miles away!) Erupted in 1883 in Java/Sumatra Erupted in 1883 in Java/Sumatra Produced a tsunami that killed 36,000 Produced a tsunami that killed 36,000

Tambora Erupted in 1815 in Indonesia Erupted in 1815 in Indonesia Killed 10,000 immeadiately Killed 10,000 immeadiately 82,000 starved to death 82,000 starved to death Caused worldwide issues Caused worldwide issues

Mount St. Helens Erupted outside Seattle, Washington in 1980 Erupted outside Seattle, Washington in 1980 Killed 65, most of swallowing hot ash Killed 65, most of swallowing hot ash Destroyed 232 square miles Destroyed 232 square miles