6th grade Science chapter 7 Earthquake Test MBMS

intensity (in earth science)

the amount of damage caused by an earthquake

epicenter

the point on Earth's surface directly above an earthquake's starting point, or focus

8b. What earthquake factors does the Moment Magnitude scale measure and report?

the size of the area of the fault that moves and how much it moves.

elastic rebound

the sudden return of elastically deformed rock to its undeformed shape

focus

the location within Earth along a fault at which the first motion of an earthquake occurs

seismic wave

a wave of energy that travels through the Earth and away from an earthquake in all directions

seismic gap

an area along a fault where relatively few earthquakes have occurred recently but where strong earthquakes have occurred in the past

2. The news reported that there was an earthquake measuring 6 on the Richter Scale. There was an after shock that was 5 on the Richter Scale. How many times bigger was the first main earthquake than the aftershock?

The earthquake was 10 times stronger because when it goes up 1 it is times 10.

1. How are the focus and the epicenter related?

The epicenter is directly above the focus which is location where the first motion occurs inside the earth.

8. What earthquake measurement scale do most scientists use?

1. The Moment Magnitude Scale

4. What are four factors that affect intensity (how much damage is done) of an earthquake.

1. size of the earthquake 2. type of construction 3. Distance from the epicenter 4. The local geology

9. If you were going to constuct an earthquake resistant building, what materials would you use in its construction and why?

I would use wood and steel for a building because they are more flexible than brick or concrete.

5. Why might an earthquake have more than one intensity value? Explain.

Intensity values are higher in the areas closest to the epicenter and less the farther away than the epicenter.

3. b. Name 2 things the Mercalli intensity Scale reports

Intensity, how much it is felt by people and how much damage was done

6 b. Why is house B a better choice for Sam?

It is better because it is anchored in rock.

8c. Why do they consider the Moment Magnitude scale the best one to use?

It is measures the physical effects that take place at the source of an earthquake better than the Richer Scale because it shows movement and size as well as strength.

6. Sam is buying a house near the Hayward fault. The soil engineer reports that House A is built on sandy soil near the bay. House B is anchored in granite. a. What is likely to happen to the soil under House A during an earthquake? How would it affect house A?

Liquifaction will cause the ground under his house to settle and the house will collapse. When seizmic waves travel through soil with water sand grains lose contact with one another and shake more during an earthquake.

3. c. Name 2 things the Richter scale reports

Magnitude, ground movement to describe magnitude

3. a. What is the difference between magnitude and intensity?

Magnitude- the measure of an earthquake's strength Intensity- how an earthquake is felt by people, amount of damage

10. Briefly explain how triangulation is used to locate an earthquakes epicenter.

You measure how long it took seismic waves to get to a 3 seismometer stations. Three circles are drawn on a map, then we find where all three circles meet up. The place they meet up is where the epicenter is.

tsunami

a giant ocean wave that forms after a volcanic eruption, submarine earthquake, or landslide

magnitude

a measure of the strength of an earthquake

earthquake

a movement or trembling of the ground that is caused by a sudden release of energy when rocks along a fault move

7.a. The Modified Mercalli Scale reports/measures this

intensity

7b. The Richter Scale reports/measures the ___ of an earthquake

strength

7c. The Moment Magnitued Scale measures/reports this

strength, movement and size of area affected