7.1.2 Prediction for the amplitude of long waves using atmospheric pressure above East China Sea

We can predict approximate values for meteotsunami parameters, including long-wave amplitude, based on real-time variation in atmospheric pressure at several sites in East China Sea. If we obtain atmospheric-pressure data from barometers at plural islands, such as Danjyo Islands and Uji islands, shown in Figure 5, far from the west coasts of Kyushu, we can imagine the propagation direction of atmospheric-pressure waves and predict the possible largest long-wave amplitude H in East China Sea, by applying the proposed Eq. (10). It is, however, difficult to place barometers at several islands, including uninhabited islands, far from the main island of Kyushu, and the maintenance of the barometers, with sustainable data transfer units, is a hard task. As long as we obtain time variation in atmospheric pressure only at one site, we can predict the possible largest amplitude H, by applying Eq. (10), although the accuracy of H is low, for the propagation direction of the atmospheric-pressure waves is not clear.

f. River banks are constructed in consideration of meteotsunamis ascending rivers, as well as downflows due to heavy rain. The wave height of nonlinear tsunamis due to a submarine earthquake increases, when they travel upstream along a river with relatively narrow width, depending on the mouth shape of the river, according to the numerical results from the three-dimensional

Long-Wave Generation due to Atmospheric-Pressure Variation and Harbor Oscillation…

The coastal structures are permitted to be built considering cost effectiveness, nearshore environment, etc., such that nonstructural measures, including evacua-

a.When a meteotsunami is predicted to be generated in the ocean, fishing boats and vessels are put offshore, if it is not stormy; if it is possible, they are put up on the land. Otherwise, mooring ropes should be tied firmly to prevent the flowage of fishing boats. If the ropes are too short, boats and vessels may be damaged when they collide with seawalls, or go on shore, owing to water level rise and onshore currents. Conversely, when the water level lowers, boats are hung by mooring ropes, as sketched in Figure 37, and they become upsidedown, after which they are waterlogged as the water level rises. Note,

however, that if mooring ropes are too long, boats are damaged owing to their collisions, such that bumpers should be attached to both boats and seawalls, unless the mooring positions are not moved to calm spots in harbor oscillation.

Mooring facilities should be developed for temporary mooring at calm

A fishery boat hung by a mooring rope, as the water level lowers owing to meteotsunamis.

b.Waterproof tools, such as waterproof walls and sandbags, should be prepared for inundation of architectures including houses, shops, fishery facilities, factories, etc. Figure 38 shows the examples of waterproof walls, equipped at Kinki Area Seaside Disaster Prevention Center in Osaka Prefecture, Japan.

tion and preparation against meteotsunamis, are necessary as follows:

calculation [19].

7.3 Nonstructural measures

DOI: http://dx.doi.org/10.5772/intechopen.85483

positions against meteotsunamis.

Figure 37.

105

If fishing cooperatives and town offices obtain GPV atmospheric-pressure data, presented by JMA, to find out an atmospheric-pressure wave traveling east, they can predict the propagation direction, as well as the possible largest amplitude, of long-waves in East China Sea, where the accuracy of the predicted parameters is improved using Eqs. (8) and (9). It is important to catch every occurrence of large secondary undulation easily, even though both predictive accuracy and hitting ratio are relatively low. The fishing cooperatives and town offices, where the simple derivation process of Eqs. (8)–(10) is preferably understood, should be aware of the importance of the daily monitoring for variation in atmospheric pressure as a routine work.
