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| Titel |
Tsunamigenic Ratio of the Pacific Ocean earthquakes and a proposal for a Tsunami Index |
| VerfasserIn |
A. Suppasri, F. Imamura, S. Koshimura |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 12, no. 1 ; Nr. 12, no. 1 (2012-01-17), S.175-185 |
| Datensatznummer |
250010415
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| Publikation (Nr.) |
 copernicus.org/nhess-12-175-2012.pdf |
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| Zusammenfassung |
| The Pacific Ocean is the location where two-thirds of tsunamis have occurred,
resulting in a great number of casualties. Once information on an earthquake
has been issued, it is important to understand if there is a tsunami
generation risk in relation with a specific earthquake magnitude or focal
depth. This study proposes a Tsunamigenic Ratio (TR) that is defined as the
ratio between the number of earthquake-generated tsunamis and the total
number of earthquakes. Earthquake and tsunami data used in this study were
selected from a database containing tsunamigenic earthquakes from prior 1900
to 2011. The TR is calculated from earthquake events with a magnitude
greater than 5.0, a focal depth shallower than 200 km and a sea depth less
than 7 km. The results suggest that a great earthquake magnitude and a
shallow focal depth have a high potential to generate tsunamis with a large
tsunami height. The average TR in the Pacific Ocean is 0.4, whereas the TR
for specific regions of the Pacific Ocean varies from 0.3 to 0.7. The TR
calculated for each region shows the relationship between three influential
parameters: earthquake magnitude, focal depth and sea depth. The three
parameters were combined and proposed as a dimensionless parameter called
the Tsunami Index (TI). TI can express better relationship with the TR and
with maximum tsunami height, while the three parameters mentioned above
cannot. The results show that recent submarine earthquakes had a higher
potential to generate a tsunami with a larger tsunami height than during the
last century. A tsunami is definitely generated if the TI is larger than
7.0. The proposed TR and TI will help ascertain the tsunami generation risk
of each earthquake event based on a statistical analysis of the historical
data and could be an important decision support tool during the early
tsunami warning stage. |
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