Earthquakes And Seismic Waves

Syncline

A fold in a rock that bends downward into a v shape

Anticline

A fold in rock that bends upward into an arch

Plateau

A large area of flat land elevated high above sea level. Some plateaus form when forces in earths crust push up a large , flat block of rock.

Explain how geologists use seismic waves to locatean earthquakes epicenter

A seismograph records and measures seismic waves and to assign a magnitude to an earthquake you use the data from seismographs

Surface waves

Move more slowly than p waves and S waves, but they can produce severe ground movements

What type of fault does tension create

Normal faults

How does stress change earths crust

Tension, compaction, and shearing, work over millions of years to change the shape and volume of rock.

How is an epicenter located

The amount of earthquake damage or shaking that is felt is rated using the modified mercalli scale. the magnitude, or size, of an earthquake is measured on a seismograph using the Richter scale or moment magnitude scale.

Focus

The area beneath earths surface where rock that was under stress begins to break or move. Where the earthquake starts.

What is a hanging wall

The block of rock that slits over the fault

How do folded mountains form

The collision of two plates can cause compression and folding of the crust over a wide area. Folding produces some of the worlds largest mountain ranges.

Normal fault

The fault cuts through rock at an angle, so one block of rock sits over the fault, while the other block lies under

P waves

The first waves are seismic waves that compress and expand the ground like an accordion.

Which way does the hanging wall move at a normal fault

The hanging wall moves down and the footwall moves up

Which way does a hanging walk move at a reverse fault

The hanging wall moves up

Describe the modified mercalli scale. Explain why it is useful.

The modified mercalli scale rates amount of shaking from an earthquake. This scale is useful in regions where there aren't many instruments to measure an earthquakes streanth.

Epicenter

The point on the surface directly above the focus, where you feel the earthquake.

What is a seismogram

The record of an earthquakes seismic waves produced by a seismograph

What is a footwall

The rock that lies under the fault

What movement occurs at a strike-ship fault

The rocks on either side of the fault move past each other sideways, with little up or down motion.

What is tension

The stress force that pulls on the crust and thins rock in the middle

What is compression

The stress force that squeezes rock until it folds or breaks

Why can't geologist predict exactly when and where earthquakes will strike

There is no way to predict

Richter scale

These scales are based on the earliest magnitude scale

What are seismic waves

Vibrations that are similar to sound waves. They travel through earth carrying energy released by an earthquake.

This is the point in Earth's surface where rocks break under stress and cause and Earthquake

What is a focus?

This is the type of scale that measures the amount of shaking that takes place within an earthquak

What is a modified mercalli scale?

This is the type of scale that measures the total amount of energy released by an Earthquake

What is a moment magnitude scale?

This is the type of fault that tension creates

What is a normal fault?

When an earthquake occurs this type of wave arrives first at a certain location.

What is a p wave?

A seismograph uses this to record the drums vibrations

What is a pen?

This is what a large area of land elevated high above sea level is called

What is a plateau?

This is the the type of fault that compression creates

What is a reverse fault?

This is the type of fault where the Hanging Wall moves up.

What is a reverse fault?

This type of fault occurs when rocks slip past one another sideway

What is a strike-slip fault?

This is the type of seismic waves that produces the most severe ground movements and does the most damage.

What is a surface wave?

This type of seismic wave can vibrate from side to side and up and down

What is an S wave?

This can cause damage days or months after an earthquake takes place

What is an aftershock?

This is what a seismogram is

What is an instrument that measures and records seismic waves?

This is the part of the wrlpd you would want to live near if you wanted low risk of an earthquake

What is away from plate boundaries?

The squeezing together of rocks by stress is called this

What is compression?

This is how geologists locate an earthquake's epicenter

What is determine the distance of three seismograph locations from the epicenter and find where the three radius' of the circles intersect?

These are the areas in which earthquake damage is the greatest

What is near plate boundaries?

This is how a seismograph works

What is seismic waves cause the drum to vibrate, while the pen records the vibrations?

This is what stress that pushes rock in two opposite directions is called

What is shearing?

This is what the richter scale measures

What is the magnitude (size)?

This is why geologists cannot exactly where earthquakes will occur

What is they cannot control when and where the energy stored in the rocks will be released?

This is the direction that the footwall moves in a normal fault.

What is up?

This is what an anticline and a syncline are

What is upward and downward folds in rocks?

This is what seisographic data reveals

What is where future earthquakes will occur?

What is the difference between s and p waves

When S waves reach the surface, they shake structures violently. While p waves travel through both solids and liquids, S waves cannot move through liquids .

How do faults form

When enough stress builds up in rock, the rock breaks, creating a fault.

What is a seismograph

An instrument that records and measures an earthquakes seismic waves. To assign a magnitude to an earthquake geologists use data from these and other sources. The data allow geologists to estimate how much energy the earthquakes release.

What pattern do seismographic data reveal

But from past seismographic data, geologists have created maps of where earthquakes occur around the world. The maps show that earthquakes often occur along plate boundaries.

In what areas are earthquake damage the greatest

Earthquake risk largely depends on how close a given location is to plate boundary. There are a lot of earthquakes along the ring of fire.

What is the difference between the focus and the epicenter.

Epicenter is where you feel the earthquake and focus is where it starts.

Distinguish between the focus and the epicenter of an earthquake

Focus where earthquake starts epicenter where you feel earthquake

How do folds in the earths crust form

Folds are bends in rock that forms when compression shortens and thickens earths crust

What pattern do seismographs reveal

From past seismograph data, geologists have created maps of where earthquakes occur around the world. the maps show that earthquakes often occur along plat boundaries.

How do anticlines and synclines form

Geologist use the terms to describe upward and downward folds in a rock. They are found in many places were compression forces have folded the crust

Reverse fault

Has the same structure as a normal fault , but the blocks move in opposite directions.

Stress

Is a force that acts on rock to change its shape or volume

Magnitude

Is a single number that geologists assign to an earthquake based on the earthquakes size.

Earthquake

Is the shaking and trembling that results from movement of rock beneath earths surface.

How does plate movement create new landforms

Over millions of years, the forces of plate movement can change a flat plain into features such as anticlines and sync lines, folded mountains, fault block mountains, and plateaus

Moment magnitude scale

Rate the total energy an earthquake releases

What is the modified mercalli scale

Rates the amount of shaking from an earthquake.

What type of fault does compression create

Reverse fault

Describe how a seismograph works.

Seismic waves cause a simple seismograms drum to vibrate, which in turn causes the pen to record the drums vibrations.

How does a seismograph work

Seismic waves cause a simple seismograph drum to vibrate, which in turn causes the pen to record the drums vibrations

S waves

Seismic waves that can vibrate from side to side or up and down

What is shearing

Stress that pushes a mass of rock in two opposite directions

What type of fault does shearing create

Strike-slip fault