Violent Earth-Module 4(earthquakes)

Which of the following earthquake waves cause the material they pass through to compress and extend? Select one: a. P-waves b. S-waves c. Surface waves d. All of the above

( a) p wave p wave is a wave which is move through the material by compressing it after compressing it will expand so why p wave travel the material by compressing and expanding the material as its travel. below given a diagram would help u we can also understand this phenomenon by look at p wave velocity formula for earthquack. formula is given below

The Richter magnitude determination is based on measurements made on seismograms. Two measurements are needed. What are they? Select one: a. Maximum amplitude of the seismic waves and the S-P time interval. b. Maximum amplitude of the seismic waves and distance the seismic waves travel. c. Magnitude of the earthquake and distance the seismic waves travel. d. S-P interval and the distance the seismic waves travel.

(a) the S-P time interval and the Maximum Amplitude of the Seismic waves. Richter scale determines the magnitude of the earthquake. It makes use of measurement of maximum amplitude of one of the waves or the average is made. The S-P distance determines the time difference between the appearances of the two waves.

What does the S-P interval represent exactly? Choose the best answer below: Select one: a. It means you can measure the distance the waves have traveled. b. It is the time interval between the arrival of the P-wave and the arrival of the S-wave at a seismic station. c. It is the distance between the earthquake epicenter and the seismic station. d. It represents the earthquake itself.

(b) It is the time interval between the arrival of the P-wave and the arrival of the S-wave at a seismic station. S waves are the seismic waves which move slower as compared to P waves. Moreover P waves are the first to reach which is followed by the S waves. Now the S-P distance measures the time difference in the appearance of the two waves. This value is directly proportional to distance from the source of the earthquake.

What is the magnitude of an earthquake? Select one: a. It is a measurement of how big an earthquake is. b. It is a scale in which earthquakes are rated depending on how strong they are. c. It is an estimate of the total amount of energy released by an earthquake. d. It is a measurement of how strong an earthquake is based on the damage created.

(c) It is an estimate of the total amount of energy released by an earthquake. It also determines how big an earthquake is. However intensity of an earthquake is one which measures the strength of an earthquake.

Where do earthquake waves originate from? Select one: a. Earth's inner core b. The epicenter c. The focus d. The core-mantle boundary e. The ocean

(c) The focus. It is the initiation point of the seismic waves. It is from the focus that the waves are diverged into different directions depending upon the nature of waves. Epicenter is the point on the surface directly above the focus. Oceans and core-mantle boundaries do not form earthquake.

What structure do earthquakes happen along? a. Dikes b. Joints c. Faults d. Unconformities e. Folds

Faults It is the faults or cracks on Earth surface where two or more plates or the section of plates are moving in different directions and causing earthquakes.

Which type of wave below can travel through solids and liquids and is similar to a sound wave? Select one: a. P-waves b. S-waves c. Love waves d. Rayleigh waves

P-waves. S waves can travel only through solids and not liquids. P-waves are longitudinal in nature and propagate as push and pull, similar to sound waves.

In which order do earthquake waves arrive at a seismic station? Select one: a. P-waves, then S-waves, then surface waves b. S-waves, then P-waves, then surface waves c. S-waves, then surface waves, then P-waves d. Surface waves, then P-waves, then S-waves e. Surface waves, then S-waves, then P-waves

a. P-waves, then S-waves, then surface waves As the name suggests P waves are primary waves so they come first, S-waves are secondary waves so they are second in position and then comes the most destructive surface waves.

Of the choices below, which choice is not associated with earthquake destruction? Select one: a. Fires b. High winds c. Mass wasting d. Trembling Earth e. Tsunami

b. High winds The earthquake destruction is associated with Fire, Mass wasting, Trembling and Tsunami, so it is only the high winds which is not associated with earthquakes.

Which of the earthquake waves listed below cause the most amount of damage during a seismic event? Select one: a. P-waves b. S-waves c. Surface waves d. All cause equal amounts of damage

c. Surface waves Surface waves have a lower frequency than P and S waves but are most destructive in nature. They move along the surface body of the earth like ripples.