Earthquake And Epicenter

Question 1

Triangulation Method

Answer 1

Method used to pinpoint the epicenter of an earthquake by analyzing the arrival times of seismic waves at multiple recording stations.

Question 2

What is an earthquake?

Answer 2

A sudden release of energy in the Earth’s crust that creates seismic waves.

Question 3

What is the point on the Earth’s surface directly above the focus of an earthquake called?

Answer 3

The epicenter.

Question 4

True or False: The focus of an earthquake is located at the surface of the Earth.

Answer 4

False.

Question 5

What scale is commonly used to measure the magnitude of an earthquake?

Answer 5

The Richter scale.

Question 6

Fill in the blank: The __________ is a measure of the energy released at the source of the earthquake.

Answer 6

magnitude.

Question 7

What instrument is used to detect and record seismic waves?

Answer 7

Seismometer or seismograph

Question 8

Which type of seismic wave travels the fastest?

Answer 8

Primary waves (P-waves).

Question 9

What is the term for the shaking of the ground caused by seismic waves?

Answer 9

Ground motion or earthquake

Question 10

Multiple Choice: Which of the following is NOT a type of seismic wave? A) P-wave B) S-wave C) T-wave D) Surface wave

Answer 10

C) T-wave.

Question 11

What is the name of the scale that measures the intensity of shaking during an earthquake?

Answer 11

The Modified Mercalli Intensity Scale.

Question 12

True or False: Earthquakes can only occur along tectonic plate boundaries.

Answer 12

False.

Question 13

What geological feature is commonly associated with earthquakes?

Answer 13

Fault lines.

Question 14

Fill in the blank: The __________ is the area where the earthquake originates underground.

Answer 14

focus (or hypocenter).

Question 15

What type of plate boundary is most commonly associated with earthquakes?

Answer 15

Transform boundaries.

Question 16

What is the term for small earthquakes that occur in the same area after a larger earthquake?

Answer 16

Aftershocks.

Question 17

Multiple Choice: Which of the following is a common cause of earthquakes? A) Volcanic activity B) Human activities C) Tectonic movements D) All of the above

Answer 17

D) All of the above.

Question 18

What is a seismogram?

Answer 18

A record produced by a seismometer showing the seismic waves of an earthquake.

Question 19

True or False: Earthquakes can be predicted with high accuracy.

Answer 19

False.

Question 20

What is a megathrust earthquake?

Answer 20

A large earthquake that occurs at subduction zones.

Question 21

Fill in the blank: The __________ is the maximum distance from the epicenter where the earthquake can still be felt.

Answer 21

attenuation zone.

Question 22

What is the purpose of earthquake-resistant building designs?

Answer 22

To minimize structural damage and protect occupants during an earthquake.

Question 23

Multiple Choice: Which of the following cities is known for its earthquake risk? A) Tokyo B) New York C) London D) Cairo

Answer 23

A) Tokyo.

Question 24

What type of seismic wave is responsible for most of the damage during an earthquake?

Answer 24

Surface waves.

Question 25

What is the relationship between the depth of an earthquake's focus and the severity of shaking felt at the surface?

Answer 25

Shallower foci typically result in more intense shaking.

Question 26

True or False: All earthquakes are caused by natural processes.

Answer 26

False.

Question 27

What is a fault?

Answer 27

A crack in the Earth's crust along which movement has occurred.

Question 28

What is the term for the energy released during an earthquake?

Answer 28

Seismic energy.

Question 29

What is the Triangulation Method?

Answer 29

A method used to locate the earthquake epicenter ## Footnote It involves analyzing seismograms from multiple stations.

Question 30

What is the first step in the Triangulation Method?

Answer 30

Determine the time interval between the arrival of P and S waves on the seismograms from at least three different stations ## Footnote This is crucial for calculating the epicentral distance.

Question 31

How should the time interval be measured in the Triangulation Method?

Answer 31

Measure the interval to the closest second ## Footnote Accuracy in timing is essential for precise calculations.

Question 32

What type of graph is used in the Triangulation Method?

Answer 32

Distance-time graph ## Footnote This graph helps convert the S-P interval to the epicentral distance.

Question 33

What do you do with the epicentral distances in the Triangulation Method?

Answer 33

Draw circles to represent each distance on the map ## Footnote The intersection of these circles indicates the epicenter.

Question 34

What is the formula used in the Triangulation Method?

Answer 34

d = To × 100 km ## Footnote Where d is distance (Km) and To is the time difference of P-S waves (secs).

Question 35

In the formula d = To × 100 km, what does 'To' represent?

Answer 35

Time difference of P-S waves (secs) ## Footnote This value is critical for calculating the distance.

Question 36

What is the final step in the Triangulation Method?

Answer 36

Locate the point where all three circles intersect ## Footnote This point is the successfully located epicenter of the earthquake.

Question 37

Difference in arrival time between the Primary waves and Secondary waves

Answer 37

Lag time

Question 38

Seismic waves are?

Answer 38

Waves that travel THROUGH and ON the surface of the Earth that cause the vibration

Question 39

Body waves travels through Earth’s inner layer, give it’s two types and describe

Answer 39

Primary or P waves is the fastest kind because it moves through solid rock and liquid layers; push and pull rocks and liquids in the same direction Secondary or S waves is slower because it travels through solid rocks ONLY; produces swaying movement

Question 40

Name the greatest earthquake ever recorded that travelled up to 1000 kilometers, give it’s magnitude and year

Answer 40

Chilean Earthquake of 1960 with 9.5 magnitude