Topic 10 Lesson 3 Earthquakes and Tsunamis

Normal fault usually occurs in what type of plate boundary?

Normal fault usually occurs at a divergent plate boundary, where tension is pulling the plates AWAY from each other.

Explain P waves.

P or primary waves travel the FASTEST. They are the first to arrive a location on Earth's surface. P waves compress and expand the ground.

A type of seismic wave that compresses and expands the ground

P wave

What are the three types of seismic waves?

P waves, S waves, surface waves

What happens when there's a tension

Tension pulls earth's crust, stretching the rock to make it thinner, especially at the point halfway between the two pulling forces.

Identify/Match: 1. normal fault is common in what type of boundary 2. reverse fault is common in what type of boundary 3. strike-slip fault is common in what type of boundary

1. divergent 2. convergent 3. transform

What can be done if there's tsunami threat?

1. send alert via TV, radio or mobile devices 2. warning siren systems 3. evacuate if the threat has passed.

How many kinds of stress are there and what are they?

3 kinds of stress: 1. tension 2. compression 3. shearing

Where does earthquake more likely occur according to the textbook?

The "Ring of Fire" around the Pacific Ocean is where many of the world's earthquakes occur.

T/F. When tension occurs, it squeezed the rock until it breaks and bends, and at a large scale rock can get folded into mountains.

FALSE. It is compression.

T/F. Over millions of years, the forces of plate movement cannot change a flat plain into folded mountains, fault-block mountains, and other dramatic features of Earth's surface.

FALSE. Over millions of years, the forces of plate movement CAN change a flat plain into folded mountains, fault-block mountains, and other dramatic features of Earth's surface.

What is tsunami detection buoys

a technology used to record seismic data and sea level changes that used to provide tsunami warnings systems

Identify/Match. a. This type of seismic wave can be a kind of rolling motion, like ocean waves, where particles move in a pattern that is almost circular. It damage the structures on the surface. b. This type of seismic waves travel the fastest. It is first to arrive at a location on Earth's surface. It compress and expand the ground. c. This type of seismic wave travel more slowly. It can move the ground side to side or up and down

a. Surface wave b. P wave c. S wave

What quantifies the size of the earthquake

amplitudes or heights of the waves on a seismogram

Which type of stress on Earth's crust can make a slab of rock shorter and thicker?

compression

Describe reverse fault and how this occurs?

compression can produce a reverse fault, in which the hanging wall slides up and over the footwall. Reverse fault is common in convergent boundaries.

What type of landform do tension and normal faults can form?

drift valley and fault block mountains

What happens when folding occurs in a large scale.

When folding occurs on a LARGE SCALE, folds that ben d upward become mountains and folds that bend downward becomes VALLEYS.

What does magnitude mean?

is a single number that geologists use to assign to an earthquake based on the earthquake's size.

What is tsunami?

is a wave or series of waves produced by an earthquake or landslide.

The force that acts on rock to change its shape or volume is called

stress

In some cases, movement on earth's crust around faults can produce tsunamis which is a type of which processes?

surface processes

Fault block mountains are built in what type of stress?

tension

What technologies have engineers developed to reduce effects on a natural disaster?

tension ties, base isolators, cross braces, and dampers

what is footwall?

the wall that is below the fault

What is a hanging wall?

the wall with rock that is above the fault

Why it is important to develop a technology that will record seismic data and sea level changes?

to minimize damage and loss of life

What does engineers created to record seismic data and sea level changes?

tsunami detection buoys

Surface processes which is a result of movement on earth's crust is called?

tsunamis

A fault is?

A fault is a break in the rock of Earth's crust or mantle.

Describes what happens during compression

Compression squeezes rocks until it bends or breaks. When compression occurs at a large scale, rock can be folded into mountains.

How do mountain and valleys form through folding?

Compression within a plate causes the crust to deform without breaking. Folds are bends in rock that form when compression shortens and thickens Earth's crust. When folding occurs on a large scale, fold that bend upward become mountains and folds that bend downward becomes valleys.

The event when rocks get squeezed, bends and breaks and can make rock folded into mountain is called?

Compression.

Internal processes as a result of movement on earth's crust is called?

Earthquake

What factors shaped many large-scale anticlines into mountains.

Weathering and erosion.

Give an example of landslide that happened which caused tsunami

In 1958, an earthquake triggered a landslide on a mountainside on the shore of Lituya Bay, Alaska. 30 million cubic meters of rock tumbled into water at one end of the bay, producing a tsunami that swept across the bay and splashed as high as 524 meters up along the steep shoreline

Describe the normal fault

In a normal fault, the hanging wall slips down relative to the footwall. Also, a slab of crust falls away becomes a valley while the adjacent slab becomes mountains.

Why it is important for geologist to pinpoint the location of earthquake's epicenter?

It helps the geologists to identify areas where earthquakes may occur in the future.

What is an epicenter?

Point on Earth's surface directly above an earthquake's focus

A type of seismic wave that moves the ground up and down or side to side

S wave

What is an S wave?

Secondary waves, travel slowly so they arrive after P wave. It can move the ground side to side or up and down

What does seismic waves mean?

Seismic waves are vibrations that travel through earth carrying energy released by various processes, such as earthquakes, ocean storms, and volcanic eruption.

Seismograph converts energy into a visual presentation called? And how does it work?

Seismogram

What is a seismograph or seismometer? And how does it work?

Seismograph is a device use to measure seismic wave produced by the earthquake. The device converts the energy in the different waves to a visual called seismogram.

When rock is being pushed in two opposite directions, to the point that it bends and breaks, you know that this type of stress is called?

Shearing

How does shearing occurs?

Shearing occurs when rock is being pushed in two opposite directions, to the point that it bends or breaks. These types of stress can produce both folds and faults.

Stress with regards to earthquakes means?

The force that acts on rock to change its shape or volume

Give an example of reverse fault setting.

The northern Rocky Mountains were gradually lifted by the action at several reverse faults.

How does a seismogram record seismic waves?

The seismogram shows the timing of the different seismic waves with the relatively gentle P and S waves arriving first, followed by surface waves with larger amplitudes.

What is an earthquake

The shaking that results from the movement of rock beneath Earth's surface.

Earthquakes alone can cause tremendous damage, but what will happen if they occur near or below the ocean floor?

They can produce another type of disaster, tsunamis.

Which type of boundary is common for strike-slip fault

Transform boundaries

T/F. As tension pulls rock apart along normal faults, some blocks fall, leaving others elevated. Over time, the resulting mountains weather

True

When ocean floor uplift, it can form what?

Tsunamis

What type of energy is released when earthquake happens?

seismic waves.

What is a syncline

A fold in rock that bends downward to form a valley

What is an anticline?

A fold in rock that bends upward into an arch. It resembles the crest of a wave

You hear about a magnitude 8-earthquake on the news. Someone says, " That doesn't sound too bad. An 8.0 is just one more than 7.0 we had here last year." Explain why that is not the right way to think about the moment magnitude scale.

Because in every whole number increased in magnitude means increased in energy 32 - folds which means 8.0 is 10 times stronger than 7.0.

What would be the factor that would cause West Coast of United States including Alaska to be higher risk of experiencing an earthquake?

Because these locations are on the edge of several boundaries.

What is a strike-slip fault? What causes it? Describe how it occurs/happens. Give an example.

California's San Andreas Fault is a product of shearing. Walls of rock grind past each other in opposite direction, making a strike-slip fault.

How does engineers minimize the damage from large earthquake?

Engineers builds/designs buildings with tension ties, base isolators, cross braces, and dampers to absorb and scatter earthquake energy or support the building structure.

T/F. When compression occurs at a small scale, rock can be folded into mountains.

FALSE. It's when compression occurs in a large scale that rock can be folded into mountains.

T/F. The movement of Earth's massive tectonic plates does not generate tremendous force

FALSE. The movement of Earth's massive tectonic plates generates tremendous force

T/F. Ocean waves and tsunamis are basically the same.

FALSE. Unlike typical ocean waves formed by the wind, tsunami waves can involve the entire water column - every drop between the surface and the ocean floor. Tsunamis can carry tremendous energy and can be highly destructive.

T/F. In strike-slip fault, a slab of crust falls away becomes a valley while the adjacent slab becomes mountains.

False. This describes a normal fault.

T/F. Reverse fault is common in divergent boundaries; while normal fault is common in divergent boundaries

False. normal fault is common in divergent boundary; while reverse fault is common in convergent boundary.

Where does most faults occurs? Explain how this affect earth's movement or change in surface.

Most faults occurs along plate boundaries, where stress of one or more types is deforming the rock leading to changes at Earth's surface.

Describe the role that stress plays in the production of earthquakes and tsunamis.

Stress makes rock and earth's surface move. The large movement cause earthquakes and earthquakes cause landslide and or ocean floor uplift which cause tsunamis.

A type of seismic wave that move in a pattern that is almost circular and damages structures on the surface

Surface wave

The type of seismic waves that ravel along Earth's surface that usually have the largest amplitudes

Surface wave

What is a surface wave?

Surface waves form when P waves and S waves reach Earth's surface. The result can be a kind of rolling motion, like ocean waves, where particles move in a pattern that is almost circular. Surface waves damage structures on the surface.

T/F. Ocean floor uplift and landslides both cause tsunami

TRUE. Both cases causes displacement of water which cause tsunami

Pulling on Earth's crust, stretching the rock to make it thinner, especially at the point halfway between the two pulling forces is called?

Tension

T/F. Each whole-number increase in magnitude represents 32-folds increase in energy which means that the seismic waves of magnitude 9 earthquake is 10 times larger than magnitude 8 earthquake.

True

T/F. Movement on earth's crust around faults can produce destructive earthquakes which are internal processes and in some cases, tsunamis which are surface processes

True

T/F. Tension, shearing, and compression can produce both folds and faults.

True

The two sides of faults is called?

Walls

What does ocean floor uplift means?

When an area of Earth's crust moves during an earthquake and forces anything above it to move as well. Example, area on off-shore ocean floor that has been stressed for so years at a convergent boundaries can suddenly pop up, thrusting up the ocean water above it.

Describe how tension and normal faults creates/builds a new landform. What type of landforms are created?

When two plates move away from each other, tension forms numerous faults that run from each other over a wide area. A wedge of rock that has hanging walls at both faults drops down to form a DRIFT VALLEY as tension pulls the adjacent footwalls away. A wedge of rock that has footwalls at both fault rises up as tension pulls the adjacent footwalls away and builds FAULT BLOCK MOUNTAINS.

Identify the following: a. rock being PUSHED in two opposite directions, to the point that it bends and breaks. b. rock being SQUEEZED until it breaks and bends and at a LARGE scale, rock can be folded into mountains c. Earth's crust gets pulled, rock get stretched and became thinner

a. shearing b. compression c. tension

Processes that can cause released of seismic waves includes?

earthquakes, ocean storms, and volcanic eruption

When movement of earth's crust around faults produce an earthquake, it refers to what type of processes?

internal processes