M A S T E R P A G E
Seismic SeaWaves
Activity Sheet
(key)
2.4h
Characteristics of a Seismic Sea Wave
Label the following characteristics and state the average values.
A Possible Tsunami Scenario
Imagine that a magnitude 6.8 earthquake occurs 1,625 km from a coastal town on a strike-slip fault in the ocean
floor, where the water is 3.8 km deep. A wave train is generated with a speed of 650 km/hr and wavelengths of
150 km. The National Tsunami Warning Center alerts the townspeople.
1. How long will it take the tsunami to hit the coastal town?
Time = Distance / Speed = 1,625 km = 2.5 hours
650 km / hr
2. The first wave hits at 2:00 p.m. Does Jen have time to rescue the boom box left on the beach before the next
wave hits? Calculate the period of the waves. (Period is wavelength divided by speed.)
Period = Wavelength / Speed = 150 km = .23 x 60 = 13.8 min
650 km / hr
3. Describe what might happen when this seismic wave encounters the coastal town.
There would be very high and very low water with only minutes in between.
4. What could be done to prepare for this tsunami?
People could be warned to move to high ground.
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