Measurement of tsunamis in the open ocean

Kulikov, E. A.; Rabinovich, Alexander B.; Spirin, A. I.; Poole, S. L.; Soloviev, S. L.

doi:10.1080/15210608309379465

Cited by 36 publications

(24 citation statements)

References 6 publications

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“…The spectrum (3) is a monotonic function of x, which for xDt ( 1, decreases according to a x -2 power law, similar to the observed background spectra in the open ocean (KULIKOV et al, 1983;FILLOUX et al, 1991;RABINOVICH, 1997). The original version of this model was used to examine the resonant oscillations in the bays and inlets of Shikotan Island (Kuril Islands) (DJUMAGALIEV et al, 1994) and Menorca Island (Balearic Islands) (RABINOVICH et al, 1999).…”

Section: Numerical Model A: Background Waves In Barkley Sound and Albmentioning

confidence: 77%

“…These spectra are ''red,'' as their spectral energy decreases with increasing frequency, with their slope proportional to x -2 , which is typical for long-wave sea-level spectra in the open ocean (cf. KULIKOV et al, 1983;FILLOUX et al, 1991;RABINOVICH, 1997). The long ocean waves are transformed as they propagate from the open ocean onto the shelf and along the shore.…”

Section: Observations Of Background Noisementioning

confidence: 99%

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Numerical Modeling and Observations of Tsunami Waves in Alberni Inlet and Barkley Sound, British Columbia

Fine

Cherniawsky

Rabinovich

et al. 2008

Pure appl. geophys.

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Alberni Inlet is a long and narrow fjord adjacent to Barkley Sound on the Pacific Coast of Vancouver Island, Canada. Port Alberni, at the head of the inlet, was affected in 1964 by the largest Pacific tsunami waves in Canadian history. We use observations and results from two numerical models to investigate the resonant characteristics of the region and amplification of tsunami waves in Barkley Sound and Alberni Inlet. The first model (A) was forced at its open boundary with a stationary autoregressive signal, similar to the observed background noise. The second model (B) used an initial sea-level deformation from a potential earthquake off California in the southern segment of the Cascadia Subduction Zone, producing transient tsunami waves. Spectral, cross-spectral and frequency-time (f-t) analyses of the observations were used to examine the resonant properties and topographic response of the local area. The respective results show large admittance functions over a wide 0.5-0.9 cph frequency band, implying a low Q factor but high amplification of arriving waves. This unusual behavior is a result of two effects: A quarter-wave resonance of the system for its fundamental Helmholtz mode and amplification due to the narrowing of the channel cross section from Barkley Sound to Alberni Inlet. The model A numerical results agree favorably with the observations, indicating an energetic resonant mode at frequency of *0.53 cph (112 min), with its nodal line located near the entrance to Barkley Sound and amplification factor value close to 12. The results from the tsunami propagation model (B) yield spectral characteristics similar to those from the model A and from the observations. The maximum tsunami current speed for this scenario is 2.4 ms -1 in Sproat Narrows, which divides Alberni Inlet into two parts, while the largest computed wave height is 1.6 m in the northern Alberni Inlet, in the area of Port Alberni.

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Section: Numerical Model A: Background Waves In Barkley Sound and Albmentioning

confidence: 77%

Section: Observations Of Background Noisementioning

confidence: 99%

Numerical Modeling and Observations of Tsunami Waves in Alberni Inlet and Barkley Sound, British Columbia

Fine

Cherniawsky

Rabinovich

et al. 2008

Pure appl. geophys.

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“…This is typical for longwave sea level spectra (cf. Kulikov et al, 1983;Filloux et al, 1991;Rabinovich, 1997). At most stations, differences between tsunami and background spectra occur mainly within the frequency band 0.1×10 -1 to 2×10 -1 cpm (periods 100 to 5 min).…”

Section: B Spectral Analysismentioning

confidence: 99%

“…The function S 0 (ω) is smooth, monotonic and almost universal (cf. Kulikov et al, 1983;Filloux et al, 1991) and roughly described as:…”

Section: Locally Generated Tsunamis On the Coast Of British Columbia mentioning

confidence: 99%

Locally generated tsunamis recorded on the coast of British Columbia

et al. 2008

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“…Ocean signal, or long wave noise, is caused by sea level variations mainly due to fluctuations in atmospheric pressure. Kulikov et al (1983) estimate the typical amplitude of the natural long wave noise in the open ocean to be 1.5-2 cm, which adds to the residuals of tidal predictions.…”

Section: Introductionmentioning

confidence: 99%

EOF analysis of a time series with application to tsunami detection

Tolkova

2010

Dynamics of Atmospheres and Oceans

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Fragments of deep-ocean tidal records up to 3 days long belong to the same functional sub-space, regardless of the record's origin. The tidal sub-space basis can be derived via Empirical Orthogonal Function (EOF) analysis of a tidal record of a single buoy. Decomposition of a tsunami buoy record in a functional space of tidal EOFs presents an efficient tool for a short-term tidal forecast, as well as for an accurate tidal removal needed for early tsunami detection and quantification (Tolkova, E. 2009. Principal Component Analysis of Tsunami Buoy Record: Tide Prediction and Removal. Dyn. Atmos. Oceans, 46 (1-4): 62-82.) EOF analysis of a time series, however, assumes that the time series represents a stationary (in the weak sense) process. In the present work, a modification of one-dimensional EOF formalism not restricted to stationary processes is introduced. With this modification, the EOF-based de-tiding/forecasting technique can be interpreted in terms of a signal passage through a filter bank, which is unique for the sub-space spanned by the EOFs. This interpretation helps to identify a harmonic content of a continuous process whose fragments are decomposed by given EOFs. In particular, seven EOFs and a constant function are proved to decompose 1-day-long tidal fragments at any location. Filtering by projection into a reduced sub-space of the above EOFs is capable of separating a tsunami wave from a tidal component within a few millimeter accuracy from the first minutes of the tsunami appearance on a tsunami buoy record, and is reliable in the presence of data gaps. EOFs with ∼3-day duration (a reciprocal of either tidal band width) allow short-term (24.75 hour in advance) tidal predictions using the inherent structure of a tidal signal. The predictions do not require any a priori knowledge of tidal processes at a particular location, except for recent 49.5 hour long recordings at the location.

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Measurement of tsunamis in the open ocean

Cited by 36 publications

References 6 publications

Numerical Modeling and Observations of Tsunami Waves in Alberni Inlet and Barkley Sound, British Columbia

Numerical Modeling and Observations of Tsunami Waves in Alberni Inlet and Barkley Sound, British Columbia

Locally generated tsunamis recorded on the coast of British Columbia

EOF analysis of a time series with application to tsunami detection

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