volcano 1

what is a volcano

A volcano is a vent in Earth's crust through which molten rock flows.

_____are small, steep-sided volcanoes that erupt gas-rich, basaltic lavas.

cinder cone volcanoes

The release of a large amount of volcanic ash can affect Earth's ____ by blockin

climate

_____are large, steep-sided volcanoes that result from explosive eruptions of andesitic and rhyolitic lava along convergent plate boundaries.

composite volcano

Volcanoes can form along when one plate subducts under another.

convergent plate boundaries

As magma rises toward Earth's surface, the pressure on it___

decreases

at plate boundaries, magma rises in cracks between the two plates, forming volcanoes.

divergent

The bubbles affect the___of lava and the type of rock that forms as lava cools.

explosiveness

The eruption style of a volcano depends on the amount of_____dissolved in the especially the amount of dissolved water vapor.

gas

bubbles of ___ form and rise in the magma

gas

Volcanoes that are not associated with plate boundaries are called

hot spots

Molten rock that erupts onto Earth's surface is called

lava

_____travel slowly and rarely are deadly; they can last for many months or longer.

lava

Molten rock below Earth's surface is called

magma

Magma from the hot ______ rises through cracks in the crust and forms a volcano

mantle

_____form when thermal energy from an erupting volcano melts snow. The meltwater can mix with____ and ____rom the volcano, and it flows downhill.

mudflow, mud, and ash

Most volcanoes in the United States occur near the____ coast

pacific

Most volcanoes occur on or along

plate boundaries

Geologists theorize that hot spots form over ______, which are places where hot magma rises due to convection currents in the mantle

plume

Volcanic eruptions can be_____ by studying changes in the ground and patterns of earthquakes.

predicted

_____ is a fast-moving avalanche of hot gas, ash, and volcanic rock.

pyroclastic flow

the ____is the area of earthquake and volcanic activity that surrounds the Pacific Ocean.

ring of fire

_____ are large, gentle-sloped volcanoes that result from quiet eruptions of basaltic lavas along divergent plate boundaries and oceanic hot spots.

shield volcano

Viscosity of lava is higher when the magma has a high____content

silica

____is a fluid's resistance to flow.

viscosity

_____can explode out of a volcano up to 40 km into the air.

volcanic ash

_____made up of tiny particles of pulverized volcanic rock and glass, erupts explosively.

volcanic ash