摘要:

There is tremendous need for an acceleration in the rate of topographical mapping of the seafloor offshore Norway. However, the main limiting factor is the lack of adequate technology. The Continental Shelf Institute has followed up this conclusion, which came from a pilot project accomplished by the SEAMAP group in 1979. A research program in hydrographic technology was set up at IKU, including projects on positioning and navigation, acoustical hydrography, optical hydrography, and ocean dynamics. A short description is given here of some of the projects: absolute positioning of a transponder on the seafloor, development of topographical side‐scan sonar, laser bathymetry, underwater photogrammetry, remote sensing of water depth and water quality, and analysis of tidal station data along the Norwegian coast.

ISSN:0149-0419    

DOI:10.1080/15210608309379460

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

In this paper the author presents the NSWC ocean tide model of the semidiurnal principal lunar (M2) tide in an atlas of ocean tidal charts and maps. The model is the computer result of a unique combination of mathematical and empirical techniques, which was introduced, extensively tested, and evaluated by Schwiderski (1978a, 1980a, b, 1983e). The computed M2amplitudes and phases are tabulated along with all specially labeled empirical input data on a 1° × 1 ° grid system in 42° × 71° overlapping charts covering the whole oceanic globe. Corresponding global and arctic corange and cotidal maps are included to provide a quick overview of the major tidal phenomena. Significant qualitative and quantitative features are explained and discussed for proper application. In particular, the charted harmonic constants may be used to compute instantaneous M2ocean tides with an accuracy of better than 5 cm any time and anywhere in the open oceans. Limitations of this accuracy in coastal waters and border seas are mentioned.

ISSN:0149-0419    

DOI:10.1080/15210608309379461

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A two‐dimensional, vertically integrated, numerical model has been used to compute the M2and S2tidal components for the North Sea. The model has also been applied for simulation of two storm surge situations. The results of the computations are compared with sea level observations from coastal stations, and for one of the simulations a comparison with current measurements is also performed.

ISSN:0149-0419    

DOI:10.1080/15210608309379462

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

In 1980, Murty and Loomis proposed a new, objective tsunami magnitude scale based on total tsunami energy. A list of 178 tsunamigenic earthquakes during the period 1815 to 1974 was given along with estimated tsunami magnitudes. In this study, we derived the probability distribution function of tsunami magnitudes based on the assumptions that (1) the occurrences of tsunamigenic earthquakes are a Poisson process, and (2) tsunami energy is a polynomial function of tsunami recurrence time. Using the data given by Murty and Loomis, the parameters of the distribution function are estimated. Comparison with the data shows that the derived distribution is a good representation of the distribution of the Murty‐Loomis tsunami magnitude.

ISSN:0149-0419    

DOI:10.1080/15210608309379463

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The small tsunami of February 23, 1980, which originated near the southern part of the Kuril Islands was recorded by the bottom vibrotron sensor installed on the shelf near Shikotan Island and connected to the island observatory by underwater cable. The marigram of the tsunami is given and compared with marigrams obtained at shore tide gauges. Some spectral features of the records are discussed.

ISSN:0149-0419    

DOI:10.1080/15210608309379464

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The spectrum of long waves, which are a background to tsunamis, is analyzed on the basis of records of near‐bottom pressure sensors obtained in the Northwest Pacific during the first and second USA‐USSR expeditions on the investigation of tsunamis in the open ocean (1975 and 1978). Instrumental trends, tidal oscillations, and quasistationary longwave noise were contained in the records. Special filters were used to pick out small waves generated by the seismicity of the ocean bottom. A decrease of noise level from 102cm (including tides) to 10°1cm could be reached. The level of long‐wave noise is found to depend on the instrument's location. Minimal disturbances in the records were observed at stations situated on the edge of the continental slope. The influence of cyclones passing over the instrument's site is deduced. It shows an increase in noise level on Nyquist frequency (0.5 min°1), which possibly is caused by the action of swell generated by the cyclone. Seismicity of the region under investigation for the second expedition (August‐October 1978) is described, and the recurrence of tsunamis is estimated, including microtsunamis. Taking into account this analysis, records were filtered and sections corresponding to probable arrivals of tsunamis from most strong earthquakes were selected. The anomalous disturbance of ocean level with a height of about 0.5 cm was found. Presumably, it was generated by an earthquake with magnitude M = 6.

ISSN:0149-0419    

DOI:10.1080/15210608309379465

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Arguments are presented to justify midocean tsunami measurements and related investigations aimed toward improvement of tsunami prediction and warning. It is postulated that midocean tsunami signatures be measured simultaneously at several locations and correlated with high‐accuracy onshore measurements.

ISSN:0149-0419    

DOI:10.1080/15210608309379466

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0149-0419    

DOI:10.1080/15210608309379467

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Identification of Seismic Sources—Earthquake or Underground ExplosionProceedings of the NATO Advanced Study Institute held at Voksenåsen, Oslo, Norway, September 8–18, 1980, edited by E. S. Husebye and S. Mykkeltveit. (Dordrecht, The Netherlands: D. Reidel Publishing Company, published in cooperation with NATO Scientific Affairs Division, NATO Advanced Study Institute, Series C, Vol. 74, 1981), 876 p.

ISSN:0149-0419    

DOI:10.1080/15210608309379468

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0149-0419    

DOI:10.1080/15210608309379469

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor