Term
| What are the products of volcanic activity? (3) |
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Definition
| lava flows, pyroclastic debris, and gas |
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Term
| Why does basaltic mafic lava have a very low viscosity? |
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Definition
| it contains relatively little silica and is very hot |
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Term
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Definition
| pea sized fragments of glassy lava |
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Term
| What components does the viscosity of lava/magma flow depend on? (4) |
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Definition
chemical composition (silica
temperature
gas content
crystal content |
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Term
| What does the character of a lava flow depend on? |
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Definition
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Term
| Medium viscosity creates what? |
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Definition
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Term
| High viscosity creates what? |
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Definition
| rhyolitic lava flow (builds a dome) |
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Term
| How does pillow lava form? |
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Definition
| form from lava flowing under water because it cools fast |
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Term
| What speed does Basaltic lava flow travel? |
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Definition
|
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Term
| how hot is basaltic mafic lava? |
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Definition
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Term
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Definition
|
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Term
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Definition
| lava flow that has a warm, pasty surface wrinkled into a smooth glassy, rope like ridge |
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Term
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Definition
| lava shaped as sharp angular fragments, creating a rubbly flow |
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Term
| What is columnar jointing? |
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Definition
| during final stages of cooling, lava flows contract because they lose heat thus creating fracture into polygonal columns |
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Term
| Where do flood bassalts occur? (2) |
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Definition
| Dekkan Traps, Columbia River Plateau |
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Term
| What can result from Basaltic lava flows? (6) |
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Definition
| flood basalts, pahoehoes, aa, lava tubes, pillow lavas and columunar jointing |
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Term
| What makes up Andesitic lava? |
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Definition
| erupts explosively, has a high gas content, viscous due to trapping gas and building pressure, relatively high silica content, high viscosity |
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Term
| What is the most common type of lava flow? |
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Definition
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Term
| Which lava flow is the most viscous of all? and Why? |
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Definition
| Rhyolitic lava, it it the most silicic and coolest |
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Term
| What does rhyolitic lava form? |
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Definition
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Term
| What degrees does rhyolitic lava range from? |
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Definition
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Term
| Where do Basaltic volcanoes occur? (3) |
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Definition
| mid ocean ridges, columbia plateau and Hawaiin islands |
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Term
| Where do andesitic volcanoes occur? (2) |
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Definition
| mt. St. Helens, mount rainier |
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Term
| Where do rhyolitic volcanoes occur? |
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Definition
| yellowstone national park |
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Term
| what produces pyroclastic debris? |
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Definition
| produced by explosive erruptions |
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Term
| what is pyroclastic flow? |
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Definition
| gravity drieven down slopes |
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Term
| What are types of pyroclastic debris? (6) |
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Definition
| pumice, volcanic bombs, ash, volcanic black, welded tuff, lapilli |
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Term
| What types of pyroclastic debris result from andesitic or rhyolitic eruptions? (7) And Why? |
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Definition
ash, pumice lapilli, accretionary lapilli, pyroclastic flow, tephra, tuff and ignimbrite
because these types are more explosive |
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Term
| What is pyroclastic flow? What were they once known as? |
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Definition
avalanche-like current
nuees ardentes-mixture of hot ash, dust and gas, fast and dangerous |
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Term
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Definition
| wet, ash rich debris flows |
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Term
| most magma contains dissolved gases included which? (4) |
|
Definition
| water, carbon dioxide, sulfur dioxide and hydrogen sulfide |
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Term
| Generally lava with more silica content contains a greater proportion of what? |
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Definition
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Term
| WWhat are the elements of a volcano? (6) |
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Definition
| magma chamber, central vent, fissures, crater, volcanic dome and caldera |
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Term
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Definition
| a crack where lava errupts underground |
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Term
|
Definition
| a big circular depression up to thousands of meters across and up to seveeral hundred meters deep |
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Term
| Where can you find a Caldera? |
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Definition
|
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Term
|
Definition
| the sudden draining of magma during major erruptions such as rhyolitic |
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Term
| describe shield volcanoes |
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Definition
| low viscosity basaltic lavas or large pyroclastic sheets, they are braod and gently sloping. material originates in the mantle |
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Term
| Explain what cinder cones are. |
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Definition
| contain pyroclastics only, have high gas content, shaped like deep craters with steep sides, small and short lived |
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Term
| Define composite/strato volcanoes. |
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Definition
| contain alternating pyroclastic layers and lava flows, produce intermediate lava flow (andesitic), |
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Term
| Where can you find composite strato colcanoes? |
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Definition
| Pacific belt, mediterranean belt |
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Term
| What is effusie eruptions? |
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Definition
| low-viscosity lavas, lava flows (basaltic) |
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Term
| What are explosive eruptions? |
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Definition
| high-viscosity, gas rich lavas with pyrolastic deposits (andesitic, rhyolitic) |
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Term
| What are phreatomagmatic eruptions? What causes them? |
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Definition
| steam explisions caused by contact of magma with ground wter or seawater |
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Term
| Where do volcanoes form/errupt? (5) |
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Definition
| island arcs, continental arcs, rifts, hot spots and mid ocean ridges |
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Term
| Oceanic hot spots can be found where and can form what? |
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Definition
| Hawaii, basaltic magma and hot spot tracks |
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Term
| Continental hot spots can form where and can form what? |
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Definition
| Yellowstone can form basaltic magma and/or rhyoltic pyroclastics |
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Term
| When do flood basalt eruptions occur? What can they form? |
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Definition
When large sheets of low viscosity lava erupt out of fissures
can form plain or plateaus |
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Term
| Where can flood vasalt eruptions be found? |
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Definition
| Columbia river basalt, deccan traps india |
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Term
| Where can you find a mound of basalt that protrudes above the sea? How did it form? |
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Definition
| Iceland, the island formed where a hot spot lies beneath the Mid-atlantic ridge |
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Term
| What causes fissure eruptions? |
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Definition
| eruptions along mid-ocean ridges |
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Term
| What hazards can vocanic eruptions cause? (9) |
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Definition
| lava, ash, pyroclastic flows, lahars, landslides, floods, earthquakes, tsunamis, and volcanic gases |
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Term
| What volcanic hazard is the most dangerous to humans and why? |
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Definition
| pyroclastic flows because they travel fast, far and are very hot |
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Term
| how does a volcanoe qualify for being dormant? |
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Definition
| has not erupted during the past 10,000 years |
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Term
| How can you predict volcanic eruptions? (4) |
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Definition
| siezmicgraphs from earthquakes, change in heat flow, change in shape, increase in gases and stream |
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Term
| What is the largest shield voclano in our solar system and where can it be found? |
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Definition
| Olympus Mons, can be found in Mars, it is extinct |
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Term
| What planets can you find active volcanism on? (2) |
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Definition
| The moons of jupiter and saturn |
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