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| Titel |
Plate Boundary Observatory Borehole Strainmeter Recordings Of The 29 September 2009 Tsunami |
| VerfasserIn |
Kathleen Hodgkinson, David Mencin, Adrian Borsa, Mike Jackson |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250041679
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| Zusammenfassung |
| On 29 September 2009 a M8.3 earthquake on the Australian-Pacific plate boundary generated a tsunami that caused widespread damage in Samoa, American Samoa, and Tonga. Peak to trough wave heights of 314 cm were recorded 250 km from the epicenter at Pago-Pago, American Samoa approximately 20 minutes after the event. NOAA’s West Coast and Alaska Tsunami Warning Center predicted the tsunami would arrive at Tofino, Vancouver Island, British Columbia, at 05:12 UTC, 30 September 2009.
The Plate Boundary Observatory has installed 74 borehole strainmeters along the western United States for the purpose of recording short-term strain transients associated with plate boundary deformation. Two of these strainmeters, Ucluelet and Bamfield, are located on the west coast of Vancouver Island within a few hundred meters of the shore. A third, Port Alberni, is located at the eastern end of Port Alberni Inlet, ~ 50 km inland. The Ucluelet and Bamfield strainmeters recorded signals associated with the arriving tsunami at times consistent with that recorded by tide gauges at Tofino and Bamfield, ~05:45 UTC. A much smaller signal was recorded about 24 minutes later at Port Alberni. The tsunami strain signals were below the detection level of PBO GPS on the Oregon coast and seismometers in the strainmeter boreholes. Strainmeters, or lower coast tiltmeters, could potentially, provide a reliable onshore detection of a tsunami. In this presentation we document the nature and frequency content of the tsunami signal as recorded by PBO strainmeters and compare these strain measurements against the crustal loading signature predicted by water height changes at nearby tide gauges |
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