Geoscience Reference
In-Depth Information
regional bathymetry, seismicity, tectonics, vulcanism and on settlements in coastal
regions, and, also, about the regional network of mareographic observations.
An important advantage of this informational resource is a specialized graphical
shell, the construction of which is based on the technological principles of state
informational networks and which provides convenient means for users to select,
visualize and process data, and, also, to analyse the quality and completeness of
historical catalogues. The cartographic shell includes means for working with raster
images of the earth's surface and of the sea-floor, which permits the user to create
digital maps of the area of interest and to subsequently superimpose observational
data on them.
For application of the shell in tsunami warning services it has a special option—
the 'New event' mode, permitting to realize selection of historical data within a
circular vicinity of the event, undergoing operative processing. The built-in subsys-
tem for estimation of the tsunami hazard permits to obtain estimates of the long-
term tsunami hazard for coastal areas of the Pacific aquatorium, for which there
exist sufficient observations of tsunami heights. The fields in which the created
database is applied comprise scientific research and developments in the field of
marine geophysics, seismology and oceanology, related to studies of natural catas-
trophes, the seismicity of the World Ocean and seismoproof building projects in
coastal regions.
An example of graphical presentation of material is given in Fig. 1.4 by the dis-
tribution of sources of tsunamigenic earthquakes in the Pacific region that occurred
during the period from 47 BC up to 2004.
An idea of the tsunami recurrence frequency can be obtained from Fig. 1.5, in
which it is shown how the number of tsunamis (per decade) varied between 1800
and 2005. All the events are divided into two categories: the grey lines indicate
significant tsunamis of intensities (the Soloviev-Imamura scale) I
1, the dark lines
Fig. 1.4 Distribution of tsunami sources in the Pacific region within the period from 47 BC up to
2004. The sizes of the circles correspond to earthquake magnitudes and their colours to the tsunami
intensities (see also Plate 1 in the Colour Plate Section on page 309)
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