Tsunami
are difficult to measure because many factors, such as
shape of ocean floor, shape of coast, size and location
of earthquake generating the tsunami, can effect their
size and destructive potential. Often tsunami are measured
after the event by looking at the damage. However, like
earthquakes, a comparison of intensity can give an idea
of the destructive potential.
The chart below gives some general information
on relating wave size and damage. It was recreated from
information found at this site.
| Intensity level |
Height in meters |
Description |
Frequency in the Pacific region |
| 1 |
2 |
Moderate with flooding of gently sloping coasts,
slight damage. |
1 per 8 months |
| 2 |
4 |
Large with flooding of shore, some light damage
to structures. |
1 every year |
| 3 |
8 |
Very large with general flooding and heavy damage
to shoreline structures. |
1 every 3 years |
| 4 |
16 |
Disastrous with almost complete destruction of structures. |
1 every 10 years |
