Samoa Tsunami at Napier
| Time of arrival of first wave* | 7.4 h |
| Height of the first wave | 0.016 m |
| Time of arrival of highest wave* | 37.1 h |
| Height of the highest wave | 0.156 m |
| Period of the highest wave | 11.0 min |
* hours after the earthquake.
Commentary
The largest waves had periods of about 15 min, indicating a likely seiche period that was excited. The maximum wave height occurred in a group of waves 37.1 h after the earthquake, probably as a result of superposition of waves coming from various directions. This indicates that sea levels need to be watched for at least a couple of days after the earthquake.
Figure 1. Samoa tsunami at Napier showing:
A. long wave record, denoised to remove spurious waves;
B. height of each wave; and
C. period of each wave.
EQ denotes the time of the earthquake (17:48 on 29 Sep 2009, UTC).
Figure 2. Samoa tsunami at Napier showing:
A. raw long wave record;
B. distribution of significant wave height with time and period.
EQ denotes the time of the earthquake (17:48 on 29 Sep 2009, UTC).
How were these calculated?
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