 |
| Titel |
The Samoa tsunami of 29 September 2009: Field survey in Tonga and preliminary modeling |
| VerfasserIn |
E. A. Okal, H. M. Fritz, J. C. Borrero |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250037739
|
|
|
|
|
|
| Zusammenfassung |
| The two northernmost islands in Tonga, Niuatoputapu and Tafahi,
were hit hard by the Samoa tsunami of 29 September 2009, with
considerable devastation on the former, where nine people
were killed.
A surveying team consisting of HMF and EAO visited the islands
in late November. On Niuatoputapu, we document extreme inundation
reaching 600 m on the Southern coast, and a complete overrun of the
Northeastern tip at Hikuniu Point, with flow depths reaching 10 m
for a total wave height of 16 m.
The forests were totally destroyed, and apparently provided no
barrier to waves of such height. On the small stratovolcano island of Tafahi,
run-up reached 22.8 m on the lee side of the island. The three villages of
Niuatoputapu were provided a relative level of protection by the fringing coral
reef present on the Northern shore. Seven of the nine victims were riding
in a pick-up truck on a road parallel to the coast.
One point, with run-up of 4 m, was also surveyed on the island
of Niuafo'ou, 200 km further West.
We present a number of numerical simulations, using several models of
the seismic source, which correctly predict enhanced amplitudes in the
direction of the Northern Tonga Islands as a result of focusing by
shallow bathymetry at the bend marking the Northern end of the
Tonga subduction zone. |
|
|
|
|
|
|