Volcano Stations REVIEW ANSWERS

ANSWER 1.Why are volcanoes considered a “window” into the Earth’s interior? They allow us to study material that comes from deep within the crust and possibly from parts of the mantle.

ANSWER 2.What is the difference between a lava flow and a pyroclastic flow? Lava flows are molten rock while pyroclastic flows are rock fragments, dust, ash & gases

ANSWER 3.(a) Besides water, what makes magma explosive? High Silica content. (b) Where do explosive volcanoes get their high water content in their magma? Explosive volcanoes occur along subduction zones where ocean water also becomes subducted with the plate.

ANSWER 4.(a) Which pyroclastic material is about the size of a quarter? –Lapilla (cinders) (b) Provide THREE ways pyroclastic flows can be deadly: –Speed of the cinders –Extreme heat –Poisonous gas

ANSWER 5. What is the difference between pahoehoe lava and aa lava? Its viscosity – pahoehoe has high viscosity (flows slowly), while aa has low viscosity (flows quickly) Pahoehoe lava aa lava

ANSWER 6. Identify the volcanoes pictured below as either explosive or nonexplosive? (A) Aleutian Island Volcano - EXPLOSIVE (D) Mayon Volcano, Philippines - EXPLOSIVE (B) Kilauea eruption - NONEXPLOSIVE (C) Eruption along midocean ridge - NONEXPLOSIVE

ANSWER 7. Identify the pictures below as one of the THREE types of volcanoes. (A) Mount Fuji, Japan – STRATOVOLCANO (B) Iceland volcano – SHIELD VOLCANO (C) Sunset Crater, Arizona – CINDER CONE

ANSWER 8. Explain how composite (strato) volcanoes are made in layers. These types of volcanoes alternate between having lava flows and then producing pyroclastic material so the sides are built by layers of these 2 types of material

ANSWER 9. How does solid rock in the asthenosphere become liquid in a magma chamber of a volcano? As rock in the asthenosphere rises from differences in temperature & density, pressure decreases allowing the putty like rock to melt and rise into a magma chamber.

ANSWER 10. How can a volcano affect global temperature? The volcanic dust and sulfur gas stay suspended in the atmosphere for long periods of time (possibly years) spreading across the globe and blocking the amount of solar radiation reaching the Earth. Redoubt in Alaska Mount Pinatubo