EARTHQUAKESEARTHQUAKES

Practice for 6Practice for 6thth grade quiz grade quiz

Ms. Cooper’s classMs. Cooper’s class

Korematsu Elementary SchoolKorematsu Elementary School

What does the term What does the term “plastic” mean when “plastic” mean when describing the upper describing the upper

mantle?mantle?

Able to change shape Able to change shape without breaking without breaking

What is a fault?What is a fault?

• A place on the Earth’s surface that breaks during an earthquake

Describe “stick-slip motion” Describe “stick-slip motion” and tell what it causes.and tell what it causes.

When the crust of two plates When the crust of two plates are stuck on each other. are stuck on each other.

Energy builds up and they Energy builds up and they suddenly slip causing an suddenly slip causing an

earthquakeearthquake

What kind of energy builds up What kind of energy builds up when the crust of two plates when the crust of two plates

are stuck while the upper are stuck while the upper mantle keeps moving?mantle keeps moving?

Potential EnergyPotential Energy

What is the point below What is the point below the surface where rock the surface where rock

breaks causing an breaks causing an earthquake called?earthquake called?

The FocusThe Focus

What do we call the point What do we call the point on the Earth’s surface on the Earth’s surface during an earthquake during an earthquake

where the seismic waves where the seismic waves are the strongest?are the strongest?

The EpicenterThe Epicenter

Where do shallow focus Where do shallow focus earthquakes occur?earthquakes occur?

In the crust less than 50 In the crust less than 50 km below the surfacekm below the surface

Where do deep focus Where do deep focus earthquakes occur?earthquakes occur?

At subduction zones when At subduction zones when the plate breaksthe plate breaks

What is a “slickensides”?What is a “slickensides”?

Exposed rock Exposed rock that has been that has been polished from polished from another mass another mass

of rock of rock moving moving

against itagainst it

Why is it better to have Why is it better to have frequent earthquakes along frequent earthquakes along a transform plate boundary a transform plate boundary

than seldom?than seldom?

If earthquakes happen If earthquakes happen frequently, the potential frequently, the potential energy can not build up energy can not build up

too high and there is less too high and there is less damage.damage.

Why do aftershocks Why do aftershocks occur?occur?

Because not all of the Because not all of the potential energy is potential energy is

released in a quakereleased in a quake

What is an instrument that What is an instrument that measures seismic waves measures seismic waves

called?called?

A seismographA seismograph

How do seismologists locate How do seismologists locate the epicenter of an the epicenter of an

earthquake?earthquake?

• The difference between arrival time of P and S waves are measured at THREE seismic stations

• The distance of the quake from each station is calculated

• A circle with the radius of that distance is drawn around each station on a map

• The point where all three circles cross is the epicenter

Which scale rates an Which scale rates an earthquake by the size of earthquake by the size of

its seismic waves?its seismic waves?

The Richter ScaleThe Richter Scale

Which scale rates the Which scale rates the damage suffered by damage suffered by

buildings, the ground and buildings, the ground and people during a quake?people during a quake?

The Mercalli Intensity The Mercalli Intensity ScaleScale