Geology Exam 2

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38 Cards. Created by Hillare ().
Important Concepts and Practice Quiz Questions Chapter 5-8

What is a volcano?

An erupting vent through which molten rock surfaces A mountain built from magmatic eruptions

Characteristics of materials produced by eruptions

three forms; lava flows, pyroclastic debris, and volcanic gases

Lava flows

molten rock that moves over the ground. three forms; 1. Low silica/high Fe and Mg 2. moderate silica, Fe and Mg 3.high silica, low Fe and Mg

Examples of Low Silica/High Fe and Mg

mafic, basaltic

Examples of moderate silica, Fe, and Mg

intermediate, andestic

examples of high silica, low Fe and Mg

silicic, felsic, rhyolitic

Pyroclastic debris

fragments blow out of a volcano

volcnic gases

vapor and aerosols that exit a volcano

The character of a lava flow dedpends on the viscosity of the lava erupts. lava is less viscous than lava and thus flows out as a __.

basaltic, rhyolitic, thin sheet

Which of the following is not a form of lava? aa, andesite, lapilli, pahoehoe


Which of the following statements is true of low viscoisty lava? 1. could build a shield volcano 2. is typically basalt 3. has low silica content 4. all of the above are true

all of the above are true

True/ False, volcanos erupt lava, pyroclastic debris and gas.


A lahar is

a volcanic mudflow and debris flow

Mafic lava erupted at a submarine will produce

a pillow basalt

which of the follwoing statements about rhyolite lava is true? 1. has more silica than basalt lava 2. indicates the tendency for explosive activity 3. forms broken adn blocky surfaces and may form a lava dome above the vent 4. all of the above statements are true.

All of the above are true.

What are tectonic boundaries along volcanics?

mor, convergent boundaries, continental rifts, and hot spots.

flood basalts are

huge sheets of low viscosity lava

Most subaerial volcanoes lie at a divergent plate boundary, true or false


pyroclastic flows bring instant death to any life caught in them, true or false


What measurable clue indiates that particular volcano may erupt in the near future

the volcano changes shape as the magma chamber fills