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| Titel |
New method to determine initial surface water displacement at tsunami source |
| VerfasserIn |
Mikhail Lavrentyev, Alexey Romanenko, Pavel Tatarintsev |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250076855
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| Zusammenfassung |
| Friday, March 11, 2011 at 05:46:23 UTC, Japan was struck by an 8.9-magnitude earthquake
near its Northeastern coast. This is one of the largest earthquakes that Japan has ever
experienced. Tsunami waves swept away houses and cars and caused massive human
losses.
To predict tsunami wave parameters better and faster, we propose to improve data
inversion scheme and achieve the performance gain of data processing.
One of the reasons of inaccurate predictions of tsunami parameters is that very little
information is available about the initial disturbance of the sea bed at tsunami source. In this
paper, we suggest a new way of improving the quality of tsunami source parameters
prediction.
Modern computational technologies can accurately calculate tsunami wave propagation
over the deep ocean provided that the initial displacement (perturbation of the sea bed at
tsunami source) is known [4]. Direct geophysical measurements provide the location of an
earthquake hypocenter and its magnitude (the released energy evaluation). Among the
methods of determination of initial displacement the following ones should be considered.
Calculation through the known fault structure and available seismic information.
This method is widely used and provides useful information. However, even if
the exact knowledge about rock blocks shifts is given, recalculation in terms of
sea bed displacement is needed. This results in a certain number of errors.
GPS data analysis. This method was developed after the December 2004 event in
the Indian Ocean. A good correlation between dry land based GPS sensors and
tsunami wave parameters was observed in the particular case of the West coast
of Sumatra, Indonesia. This approach is very unique and can hardly been used in
other geo locations.
Satellite image analysis. The resolution of modern satellite images has
dramatically improved. In the future, correct data of sea surface displacement
will probably be available in real time, right after a tsunamigenic earthquake.
However, today it is not yet possible.
Ground-based sea radars. This is an effective tool for direct measurement of
tsunami wave. At the same time, the wave is measured at a rather narrow area
in front of the radar and does not include information about neighboring parts of
the wave.
Direct measurement of tsunami wave at deep water [2]. Today, this technology
is certainly among the most useful and promising. The DART II® system
consists of a seafloor bottom pressure recording (BPR) system, capable of
detecting tsunamis as small as 1 cm, and a moored surface buoy for real-time
communications.
We focus our research on improving the later method, direct measurement of tsunami wave at
deep water. We suggest the new way to analyze DART data, modifying the methodology
originally proposed by V. Titov. Smaller system of unit sources [3] should be considered to
approximate all typical shapes of initial disturbance by several suitable basis functions. To
successfully implement it, performance of data analysis should be dramatically
improved. This could be done by using a signal orthogonalization procedure for
considered system of unit sources and calculation of Fourier coefficients of the
measured time series with respect to orthogonal basis. The approach suggested
was used as a part of computerized workstation for tsunami hazard monitoring
[5-6].
National Oceanic and Atmospheric Administration Center for Tsunami
Research. URL: http://nctr.pmel.noaa.gov/honshu20110311/
National Data Buoy Center. URL: http://www.ndbc.noaa.gov/dart.shtml
National Oceanic and Atmospheric Administration Center for Tsunami
Research. URL: http://sift.pmel.noaa.gov/thredds/dodsC/uncompressed/
National Oceanic and Atmospheric Administration Center for Tsunami
Research. URL: http://nctr.pmel.noaa.gov/model.html
Alexey Romanenko, Mikhail Lavrentiev-jr, Vasily Titov, "Modern Architecture
for Tsunami Hazard Mitigation" // Asia Oceania Geosciences Society
(AOGS-2012), ISBN 978-981-07-2049-0
Mikhail Lavrentiev-jr, Andrey Marchuk, Alexey Romanenko, Konstantin
Simonov, and Vasiliy Titov, "Computerized Workstation for Tsunami Hazard
Monitoring", Geophysical research abstracts, Vol. 12, EGU2010-3021-1, 2010 |
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