Tsunami

Question 1

Tsunami

Answer 1

Tsunami is a Japanese word
(both singular and plural) that
means ‘harbor wave’

Question 2

Crest

Answer 2

high point of the wave

Question 3

trough

Answer 3

low point of the wave

Question 4

Wave length

Answer 4

distance between two waves

Question 5

Amplitude

Answer 5

the height of wave;
the difference in elevation
between a trough and crest

Question 6

Wave period

Answer 6

the time required
for one complete wave to pass
The wave velocity (how fast the
wave moves) equals the
wavelength divided by the wave
period
Water Waves - Definitions, Characteristics, and Behavior of waves

Question 7

Waves

Answer 7

Waves are the deformed surface of a water body. They occur when the water surface is
deformed by the addition of some form of mechanical energy. While waves appear to transport
water, they actually transport energy as the deformation moves forward. Water does progress
forward by the process of Stokes Drift, but the net forward velocity of a water particle is small
compared with the wave speed.

Question 8

As a wave approaches the shore,

Answer 8

he progressively shallower water causes the
wave properties to change. The friction from the seabed slows the wave, causing
the wavelength to decrease, and the amplitude to increase. Essentially, the
energy of the wave is “compressed” into a taller, narrower column of water

Question 9

For most waves, the energy source is

Answer 9

atmospheric wind. These waves are called wind waves or surface
waves. They typically have wavelengths ranging from a few meters to a few hundred meters, and a
period ranging from a few seconds to a few 10’s of seconds. These waves are familiar to anyone who
has been to the beach or shore

Question 10

Tsunami waves are

Answer 10

formed by an entirely different process - physical displacement of an entire large
mass of water. Since the displacement may be sudden and large-scale, tsunami differ tremendously
from wind waves.

Question 11

run-up

Answer 11

All waves, including tsunami increase in amplitude (height) as they come ashore (refer to figure 10.3).
In the case of tsunami, this increase is often referred to as the run-up.

Question 12

earthquakes as a cause

Answer 12

The most common cause of major
tsunami is an underwater
earthquake. Note that most
underwater earthquakes do NOT
cause tsunami. Several conditions
are required:
1. Vertical movement - Only an
earthquake that causes vertical
movement will trigger a
tsunami. Generally, this occurs
at subduction zones when one
of the converging plates “snaps”
upward when the fault releases.
The animation shows the
process of an earthquake-
cased tsunami