Science Ch. 13 notes

What is an example of a dome mountain?

Black Hills

What causes hot spot volcanoes?

Magma from deep within the mantle rises and melts through the crust above it, often far from plate boundaries.

What process forms island arcs?

When converging plates collide, the older, denser plate dives under the other plate and sinks into the asthenosphere. There it melts and forms magma, which seeps upward, creating volcanoes that con result in an island arc.

Whats an example of a hot spot that occurs under continents?

Yellowstone National Park

Most volcanoes occur at ______________

convergent plate boundaries

Sometimes magma does not reach the surface and it ______________.

cools below Earth's surface

A batholith is a mass of rock formed when a large body of magma cooled inside the crust. Forms the _____ of many mountain ranges.

core

Low silica content= ______colored rocks (_______)

dark, basalt

Underwater volcanoes occur at _________________

divergent plate boundaries

Lava flows can cause _____.

fires

The force of a volcanic eruption depends on the amount of __________ in the magma and also the ________,_____________, and ____________.

gas dissolved, temperature, thickness, silica

Shield volcanoes form a _______mountain.

gently sloping

A sill is a slab of volcanic rock formed when magma squeezes between layers of rock in a __________ rock formation.

horizontal

Volcanoes also occur at ______.

hot spots

___________is a volcanic island on the Mid-Atlantic ridge that is growing outward in opposite directions.

iceland

Geologists monitor the ________ of the volcano to determine if magma is rising.

internal temperature

During explosive eruptions, magma is ____ and _____.

thick, sticky

Is the lava in Cinder cone volcanoes thinner or thicker than the lava in shield volcanoes?

thicker

high silica content= _______ magma.

thicker

____, ______ lava flows from the vent in quiet eruptions.

thin, runny

Hotter temperature =______ fluid= _____flowing magma.

thinner, faster

In dome mountains, rising magma within the crust is blocked by layers of rock. Magma forces layers of rock to bend _______ into a dome shape.

upward

____active volcanoes worldwide (how many)

600

What is an example of a caldera?

Crater lake in Oregon formed from the collapse of mt. mazama

What are 2 examples of quiet eruptions?

Hawaii, Iceland

Whats an example of a hot spot?

Hawaiian islands

In subduction zones, the volcanoes create a sting of islands called an _______

Island arc

Where do most volcanoes occur on Earth's surface?

Most volcanoes occur along converging plate boundaries (subduction zone).

What is an example of an explosive eruption?

Mount St. Helens in 1980

A major belt is the "_________" which encircles the Pacific Ocean

Ring of Fire

What will eventually happen to the active volcano on the island of Hawaii, which is now over the hot spot?

The volcano will no longer be active as the island of Hawaii moves with the Pacific plate and is carried away from the hot spot.

_____ can clog car engines and collapses roofs.

ash

_____- fine, rocky particles as small as a grain of sand.

ash

Most volcanoes occur in ______________

belts that extend across continents and oceans

____- larger pieces that can be as large as a car

bombs

_____- pebble-sized particles.

cinder

Eruptions can trigger _________ or avalanches of mud or snow.

landslides

Are shield volcanoes some of the smallest or largest volcanoes?

largest

When magma reaches the surface it is called _____

lava

A _____________ is formed from continued cooling of lava on level ground.

lava plateau

Liquid magma is _____dense than the surrounding solid rock, so it ______until it reaches the Earths surface or gets trapped beneath a layer of rock.

less, rises

High silica content= ______colored rocks (_______)

light, rhyolite

________is a molten mixture of rock-forming substances, gases in the mantle.

magma

Shield volcanoes have _____ eruptions.

mild

During a ______ eruption magma flows easily and gases bubble out gently.

quiet

The __________ of magma helps to determine whether the volcanic eruption is quiet or explosive.

silica content

As _______ occurs, rock is melted as it moves towards the mantle. The magma then rises to the surface and forms a volcano.

subduction

Composite volcanoes form in ___________.

subduction zones

Magma deep underground flows _____through cracks in rock. As the magma sises, the pressure ______, and dissolved gases in magma being to separate out and form bubbles. When an opening develops in ____ rock on the surface, the gases and magma erupt out of the volcano.

upward, decreases, weak

A Dike is a slab of volcanic rock formed when magma forces itself across rock layers in a ______rock formation.

vertical

Are geologist more successful predicting volcanic eruptions or earthquakes?

volcanic eruptions

A _________ is a weak spot in the crust where molten material comes to the surface.

volcano

A volcanic neck forms when magma harden in a __________.

volcano's pipe

The cooled magma below Earth's surface can be exposed by _________ over time.

weathering

Can hot spots occur under continents?

yes

Do all volcanoes have magma chambers?

yes