1.
Once the elastic limit of rocks is passed, they break and move along surfaces called ______.
Correct Answer
A. Faults
Explanation
Once the elastic limit of rocks is surpassed, they are no longer able to withstand the stress and pressure placed upon them, causing them to break. These broken rocks then move along surfaces known as faults. Faults are fractures or breaks in the Earth's crust where movement has occurred. This movement can result in earthquakes, as the rocks on either side of the fault slip or slide past each other. Therefore, faults are the correct answer in this context.
2.
The height of the lines traced on paper is a measure of the energy released of the ________of the earthquake.
Correct Answer
C. Magnitude
Explanation
The height of the lines traced on paper is a measure of the energy released of the magnitude of the earthquake. Magnitude refers to the size or strength of an earthquake and is typically measured using the Richter scale. The greater the magnitude, the more energy is released during the earthquake, which can result in larger and more destructive seismic waves. Therefore, the height of the lines traced on paper can be used as an indicator of the earthquake's magnitude.
3.
Most earthquakes happen ___________
Correct Answer
D. All of the above
Explanation
Most earthquakes happen without warning, as seismic activity cannot be accurately predicted. Additionally, earthquakes commonly occur in areas where they have happened in the past, as these regions are more prone to seismic activity. Furthermore, earthquakes often occur along plate boundaries, where tectonic plates interact and cause stress and movement. Therefore, the correct answer is "all of the above," as all three statements are true regarding the occurrence of earthquakes.
4.
Scientists discovered changes in Earth's interior by studying _______.
Correct Answer
C. Changes in seismic waves
Explanation
Scientists discovered changes in Earth's interior by studying changes in seismic waves. Seismic waves are generated by earthquakes and other geological events, and they travel through different layers of the Earth. By analyzing the properties of these waves, such as their speed, direction, and intensity, scientists can gain valuable insights into the composition and structure of the Earth's interior. Therefore, studying changes in seismic waves is an effective method for understanding the dynamics and processes occurring within the Earth.
5.
____________is the force that squeezes rocks together.
Correct Answer
D. Compression
Explanation
Compression is the force that squeezes rocks together. When rocks are subjected to compression, they are pushed together, causing them to be compressed and potentially undergo deformation. This force is commonly associated with tectonic plate movements, where rocks are pushed together, leading to the formation of mountains and other geological features.
6.
______________faults are caused by tensional forces.
Correct Answer
A. Normal
Explanation
Normal faults are caused by tensional forces. In a normal fault, the hanging wall moves downward relative to the footwall, resulting in the stretching and thinning of the Earth's crust. This type of fault occurs in areas where the crust is being pulled apart, such as in divergent plate boundaries or in regions of extensional tectonic forces.
7.
_____________faults are caused by compressional forces.
Correct Answer
C. Reverse
Explanation
Reverse faults are caused by compressional forces because they occur when the rocks are pushed together and the hanging wall moves upward in relation to the footwall. This type of faulting is commonly associated with convergent plate boundaries where two tectonic plates collide, causing compression and the formation of mountains. In reverse faults, the angle of the fault plane is steep, and the displacement of the rocks is vertical. This contrasts with normal faults, where the hanging wall moves downward in relation to the footwall due to tensional forces, and strike-slip faults, where the movement is horizontal. Elastic faults, on the other hand, refer to the ability of rocks to deform and then return to their original shape without permanent damage.
8.
The most destructive seismic wave are _____________.
Correct Answer
D. Surface waves
Explanation
Surface waves are the most destructive seismic waves because they travel along the Earth's surface and cause the ground to move in a rolling or swaying motion. These waves have a larger amplitude and longer periods compared to other seismic waves, which results in greater damage to buildings and infrastructure. Surface waves can cause extensive shaking and ground displacement, leading to landslides, collapse of structures, and other destructive effects.
9.
The ____________waves are the first to reach a seismograph after an earthquake.
Correct Answer
C. Primary
Explanation
Primary waves, also known as P-waves, are the first to reach a seismograph after an earthquake. These waves are the fastest seismic waves and can travel through both solids and liquids. They cause the ground to move back and forth in the direction of wave propagation, similar to how a slinky moves when stretched and released. Primary waves are responsible for the initial shaking felt during an earthquake and provide important information about the location and magnitude of the seismic event.
10.
At least _____________seismographs are needed to accurately locate an earthquake epicenter.
Correct Answer
D. Three
Explanation
To accurately locate an earthquake epicenter, at least three seismographs are needed. This is because seismographs record the arrival times of seismic waves at different locations. By analyzing the time differences between the arrival of these waves at different seismographs, scientists can triangulate the epicenter of the earthquake. With only two seismographs, it would be impossible to determine the exact location, as there would be multiple potential epicenters. However, with three or more seismographs, the intersection of the recorded wave paths can pinpoint the precise epicenter of the earthquake.
11.
The point in Earth's interior where the energy release of an earthquake occurs is the ___________.
Correct Answer
A. Focus
Explanation
The point in Earth's interior where the energy release of an earthquake occurs is known as the focus. This is the exact location where the seismic waves originate and spread outwards, causing the ground shaking and other earthquake-related effects. The focus is usually located deep within the Earth's crust or upper mantle, and its precise location can be determined by analyzing the arrival times of seismic waves at different recording stations. The epicenter, on the other hand, refers to the point on the Earth's surface directly above the focus, and it is commonly used to describe the location of an earthquake.
12.
The magnitude of an earthquake is measured by the _________________.
Correct Answer
A. Richter scale
Explanation
The magnitude of an earthquake is measured by the Richter scale. The Richter scale is a logarithmic scale that quantifies the amount of energy released during an earthquake. It measures the amplitude of seismic waves recorded by seismographs. The scale ranges from 0 to 10, with each whole number increase representing a tenfold increase in the amplitude of the seismic waves and approximately 31.6 times more energy release. The Richter scale is widely used to compare the size of earthquakes and assess their potential impact.
13.
_____________ is the force that pulls rocks apart.
Correct Answer
A. Tension
Explanation
Tension is the force that pulls rocks apart. When a force is applied to a rock in opposite directions, it creates tension within the rock, causing it to stretch and ultimately break. This force acts along the line of the pull, exerting a pulling or stretching effect on the rock. Tension is commonly observed in situations like the stretching of a rubber band or the pulling apart of tectonic plates, leading to the formation of faults and fractures in the Earth's crust.
14.
_______________is the force that causes plates to move sideways past each other.
Correct Answer
B. Shear
Explanation
Shear is the force that causes plates to move sideways past each other. When two plates are subjected to shear stress, they slide horizontally in opposite directions along a fault line. This movement is responsible for earthquakes and the formation of features like transform boundaries. Tension refers to the force that pulls plates apart, while compression refers to the force that pushes plates together. Elastic limit, on the other hand, is the maximum stress a material can withstand without permanent deformation.
15.
_____________faults are caused by shear forces.
Correct Answer
B. Strike-slip
Explanation
Strike-slip faults are caused by shear forces. In these faults, the rocks on either side of the fault plane slide past each other horizontally. This movement is primarily due to the shearing or lateral forces acting on the rocks. The rocks do not move vertically or compress or extend in this type of fault. Therefore, strike-slip faults are associated with horizontal displacement and are commonly found along transform plate boundaries, where two plates slide past each other.
16.
All of the following will improve safety factors during an earthquake EXCEPT to __________.
Correct Answer
B. Stand next to a window
Explanation
Standing next to a window during an earthquake would not improve safety factors. Windows can shatter during seismic activity, leading to the risk of injury from broken glass. It is important to move away from windows and take cover under a sturdy piece of furniture or in a doorway to protect oneself during an earthquake. Therefore, standing next to a window is not a recommended safety measure.