Earthquakes and Volcanoes

Question 1

What are Earthquakes?

Answer 1

the vibrations in the ground that result from movement along breaks in Earth’s lithosphere

Question 2

Where do most earthquakes occur?

Answer 2

In the ocean and along the edges of continents. Mainly along plate boundaries.

Question 3

What causes earthquakes?

Answer 3

Earthquakes result from the buildup and release of stress along active plate boundaries.

Question 4

Where do the deepest earthquakes occur?

Answer 4

Along convergent plate boundaries because the denser oceanic plate subducts into the mantle. They usually release a lot of energy and can be quite disastrous.

Question 5

Where are shallow earthquakes found?

Answer 5

Along divergent plate boundaries like the mid-ocean ridge system, or along transform plate boundaries like the San Andreas Fault.

Question 6

What is a fault?

Answer 6

A break in the Earth’s lithosphere where one block of rock moves toward, away from, or past another.

Question 7

What are the three different types of motion found along faults?

Answer 7

Sliding horizontally past each other in opposite directions (strike-slip fault and transform plate boundary)
Pulling two blocks of rock apart (Normal fault and divergent plate boundary)
Pushing two blocks of rock together (Reverse fault and convergent plate boundary)

Question 8

What type of motion is found along a reverse fault?

Answer 8

pushing two blocks of rock together

Question 9

What is rock deformation?

Answer 9

When forces, such as pressure, are applied to rock and the rock changes shape.

Question 10

what is a primary wave

Answer 10

Also called p-waves, cause particles in the ground to move in a push-pull motion similar to a coiled spring. Fastest moving seismic wave. first waves felt following an earthquake. travel through solids and liquids.

Question 11

what is a secondary wave

Answer 11

also called s-waves. slower than p-waves. cause particles to move up and down at right angles relative to the direction the wave travels. can travel through solids only

Question 12

what is a surface wave

Answer 12

cause particles in the ground to move up and down in a rolling motion similar to ocean waves. only travel on Earth’s surface closest to the epicenter. cause most damage to the surface of the Earth

Question 13

what is a seismic wave

Answer 13

energy that travels as vibrations on and in Earth

Question 14

what is a seismogram

Answer 14

a graphical illustration of seismic waves that records ground motion

Question 15

what is a seismometer

Answer 15

an instrument that measures and records ground motion and can be used to determine the distance seismic waves travel.

Question 16

what is a seismologist

Answer 16

scientists that study earthquakes

Question 17

what is the epicenter

Answer 17

The location on Earth’s surface directly above the earthquake’s surface

Question 18

what is the focus

Answer 18

where seismic waves originate where rocks first move along the fault, at a location inside Earth

Question 19

what is the mantle

Answer 19

the thick middle layer in the solid part of Earth

Question 20

what is a convergent plate boundary

Answer 20

the boundary between two plates that moves toward each other

Question 21

Where do volcanoes form?

Answer 21

Along convergent plate boundaries, divergent plate boundaries, and hot spots.

Question 22

What is the Ring of Fire?

Answer 22

An area of earthquake and volcanic activity that surrounds the Pacific Ocean

Question 23

What happens when mantle melts?

Answer 23

It forms magma. The magma is less dense than the mantle and rises through the cracks in the crust. This forms a volcano.

Question 24

What determines a volcano’s eruption style?

Answer 24

The magma chemistry. The amount of dissolved gases, specifically the amount of water vapor, a magma contains, and silica.

Question 25

What determines the viscosity of magma?

Answer 25

the amount of silica in a magma. If it has a high silica content it has a high viscosity and flows like sticky toothpaste. If it has low silica content it has a low viscosity and flows easily like warm maple syrup.

Question 26

Explain the difference between shield volcanoes and composite volcanoes?

Answer 26

shield volcanoes are common along divergent plate boundaries and oceanic hot spots. they are large with gentle slopes and basaltic lavas. Composite volcanoes are large, steep-sided volcanoes that usually result from explosive eruptions of andesitic and rhyolitic lava and ash along convergent pate boundaries.

Question 27

Molten rocks erupts from a _______

Answer 27

volcano

Question 28

______ is molten rock that flows along Earth's surface

Answer 28

lava

Question 29

A ________ is not associated with any plate boundary

Answer 29

hot spot

Question 30

A ________ is large and steep-sided, occurs along convergent plate boundaries, and results from explosive eruptions

Answer 30

composite volcano

Question 31

______ have gentle slopes of basaltic lava; they are commonly located along divergent plate boundaries and ocean hot spots

Answer 31

shield volcanoes

Question 32

A _______ is small and steep-sided, and it erupts basaltic lava

Answer 32

cinder cone

Question 33

_____ is present beneath Earth's surface

Answer 33

magma

Question 34

When magma erupts explosively, it can send particles of rock and glass, or _____ into the air

Answer 34

volcanic ash

Question 35

Magma's resistance to flow is called its _____

Answer 35

viscosity

Question 36

Magma contains _____ gases, including carbon dioxide and sulfur dioxide

Answer 36

dissolved

Question 37

A(n) ________ is a vent in Earth's crust through which molten rock flows.

Answer 37

volcano

Question 38

Molten rock below Earth's surface is called _____

Answer 38

magma

Question 39

Volcanoes can form along ______ plate boundaries, when one plate subducts under another.

Answer 39

convergent

Question 40

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

Answer 40

mantle

Question 41

Molten rock that erupts onto Earth's surface is called _____

Answer 41

lava

Question 42

At ______ plate boundaries, magma rises in cracks between the two plates forming volcanoes

Answer 42

divergent

Question 43

Volcanoes that are not associated with plate boundaries are called ______

Answer 43

hot spots

Question 44

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

Answer 44

plume

Question 45

Most volcanoes occur on or along ______

Answer 45

plate boundaries

Question 46

The _____ is the area of earthquake and volcanic activity that surrounds the Pacific Ocean

Answer 46

Ring of Fire

Question 47

Most volcanoes in the United States occur near the ______ coast.

Answer 47

West

Question 48

_____ are small, steep-sided volcanoes that erupt gas-rich, basaltic lavas

Answer 48

cinder cones

Question 49

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

Answer 49

composite volcanoes

Question 50

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

Answer 50

shield volcanoes

Question 51

_____ travel slowly and rarely are deadly; they can last for many months or longer

Answer 51

Lava flows

Question 52

_____ can explode out of a volcano up to 40 km into the air

Answer 52

Volcanic ash

Question 53

_____ form when thermal energy from an erupting volcano melts snow. The meltwater can mix with _____ and _____ from the volcano and it flows downhill

Answer 53

mudflows mud ash

Question 54

A(n) _______ is a fast-moving avalanche of hot gas, ash, and volcanic rock

Answer 54

pyroclastic flow

Question 55

Volcanic eruption can be _______ by studying changes in the ground and patterns of earthquakes

Answer 55

predicted

Question 56

_____, made up of tiny particles of pulverized volcanic rock and glass, erupts explosively

Answer 56

volcanic ash

Question 57

The eruption style of a volcano depends on the amount of ______ dissolved in the magma, especially the amount of water vapor

Answer 57

gases

Question 58

_____ is a fluid's resistance to flow. Viscosity of lava is higher when the magma has a high ______ content

Answer 58

viscosity | silica

Question 59

As magma rises toward Earth's surface, the pressure on it ______. Bubbles of ____ form and rise in the magma. The bubbles affect the _____ of lava and the type of rock that forms as lava cools

Answer 59

decreases gas idk

Question 60

The release of a large amount of volcanic ash can affect the Earth's climate by blocking ______

Answer 60

sunlight

Question 61

When droplets of sulfuric acid from volcanoes form in the atmosphere, they _____ sunlight into space

Answer 61

reflect

Question 62

Volcanic ash and acid droplets in the atmosphere _____ Earth's climate

Answer 62

affect

Question 63

_____ are the vibrations in the ground that result from movement along breaks in Earth's lithosphere

Answer 63

earthquakes

Question 64

The forces that move _____ also push and pull rocks along breaks in the lithosphere

Answer 64

tectonic plates

Question 65

Most earthquakes occur along active ____. These areas are generally in the middle of oceans or along the edges of ______.

Answer 65

plate boundaries | continents

Question 66

Deep earthquakes occur along _____ plate boundaries, where a denser oceanic plate subducts into the mantle

Answer 66

convergent

Question 67

Shallow earthquakes are common along _______ boundaries, where plates seperate

Answer 67

divergent

Question 68

Earthquakes of varying depths occur where continents _____.

Answer 68

collide

Question 69

Pressure applied to a rock can change the shape of the rock in a process called ______. This can eventually ______ the rock

Answer 69

rock deformation

Question 70

A(n) ______ is a break in Earth's lithosphere where one block of rock moves toward, away from, or past another block

Answer 70

fault

Question 71

The three main kind of faults are ______, ______, and _______

Answer 71

strike-slip normal reverse faults

Question 72

When rocks move in any direction along a fault, they release energy in Earth's crust in _______

Answer 72

seismic waves

Question 73

Seismic waves originate along the _____ where rocks first begin to move. This location inside Earth is the _______ of the earthquake

Answer 73

fault | focus

Question 74

The _____ of an earthquake is the location on Earth's surface directly above the focus

Answer 74

epicenter

Question 75

The energy released during an earthquake is strongest near the ______

Answer 75

epicenter

Question 76

An earthquake's energy travel in three kinds of _____

Answer 76

seismic waves

Question 77

_____(_____) cause particles in the ground to move in a push-pull motion similar to a coiled spring.

Answer 77

primary wave (P-waves)

Question 78

_____ (_____) move rock particles side to side and up and down at right angles to the direction that the wave travels

Answer 78

Secondary waves (S-waves)

Question 79

______ move the ground up and down and side to side in a rolling motion like an ocean wave.

Answer 79

Surface waves

Question 80

Scientists who study earthquakes are called _______

Answer 80

seismologists

Question 81

Seismic waves travel at different _______ and in different ______, depending on the materials they travel through.

Answer 81

speed | directions

Question 82

S-waves cannot travel through liquids, including Earth's ______

Answer 82

outer core

Question 83

Seismic waves _______ as they travel through hot material. From this information, scientists model convection currents in Earth's ______

Answer 83

change speed | mantle

Question 84

A(n) ______ measures and records how much the ground moves and can be used to determine the distance seismic waves travel.

Answer 84

seismometer

Question 85

A(n) _____ is a graphical illustration of seismic waves.

Answer 85

seismogram

Question 86

The ______ uses the amount of motion at a given distance from an earthquake to determine the magnitude of the earthquake

Answer 86

Richter Scale

Question 87

The _____ measures the amount of energy released by an earthquake

Answer 87

Moment Magnitude Scale

Question 88

The ________ measures earthquake intensity based on descriptions of the earthquake's effects on people and structures.

Answer 88

Modified Mercalli Scale

Question 89

In the United States, most earthquakes occur near transform faults and _____

Answer 89

convergent plate boundaries

Question 90

Seismologists assess ______ based on past earthquake activity, the geology around a fault, population density, and building design

Answer 90

risk

Question 91

What do scientists use to find the epicenter?

Answer 91

triangulation