Module 4
7.1
The page shows a nomogram with three lines representing the data you provided. Type in your estimate for the earthquake in the box provided on the webpage and click on "Confirm Magnitude". Choose the magnitude below that most closely represents the magnitude for this earthquake.
It is the time interval between the arrival of the P-wave and the arrival of the S-wave at a seismic station.
After you finish reading the page, go ahead and choose the region "San Francisco area" for your simulation of an earthquake and click "submit choice". What does the S-P interval represent exactly? Choose the best answer below:
39 seconds
Click on "Convert S-P Interval". Read the information on "Determining the Earthquake Distance". It takes an S-wave approximately 70 seconds to travel 300 km. How long does it take the P-wave to travel this same distance? Choose the best answer below
285 mm
Click on "Go to next page". Read the information on the "Richter Nomogram" and then click on "Go to next page" again. Measure the maximum amplitude of the S-wave for each seismogram and record your estimate in the box below the seismogram, then select the best answers from the choices (Questions 14, 15 & 16) below: Eureka, CA:
49 seconds
Click on "View Seismograms" at the bottom of the page. Choose the closest number that represents the S-P interval you got for each station (Questions 4, 5 & 6) below: Eureka, CA
60 mm
Elko, NV:
703 km
Elko, NV:
72 seconds
Elko, NV:
100 mm
Las Vegas, NV:
623 km
Las Vegas, NV:
64 seconds
Las Vegas, NV:
It is an estimate of the total amount of energy released by an earthquake.
Richter Magnitude Click the box at the bottom of the screen titled "Compute Richter Magnitude", then read the section on "Magnitude Explained". What is the magnitude of an earthquake? Choose the best answer from the choices below:
Maximum amplitude of the seismic waves and the S-P time interval.
The Richter magnitude determination is based on measurements made on seismograms. Two measurements are needed. What are they?
The distance between the seismic recording station and the possible earthquake epicenter.
Type in your answers above into the boxes provided on the webpage and hit "Find Epicenter". The next screen will be a map showing circles. What are these circles themselves individually depicting?
478 km
Use the S-P graph at the bottom of the webpage and the estimates you made for the S-P travel times for the three seismograms. Choose the closest number that represents the closest distance in the space below:
The Focus
Where do earthquake waves originate from?
P-waves
Which type of wave below can travel through solids and liquids and is similar to a sound wave?
