Geoscience Reference
In-Depth Information
Fig. 6.11 Example of coseismic deformation on the island Simeulue, village of Busung, due to
strong aftershock on March 28, 2005 at the coast of Indonesia (Photo by V. Kaistrenko) (see also
Plate 13 in the Colour Plate Section on page 321)
reconstruction of the positions of the ancient shoreline and of the relief height for
different moments of time. And only after this has been done it becomes possible to
determine the parameters of ancient tsunamis. In the conditions of rapid and large
uplift or subsidence of the coasts (which is peculiar to subduction zones) it is espe-
cially important to perform reconstructions. The difficulty of such work is enhanced,
also, by the coast along the subduction zones being subject to sharp coseismic ele-
vations and depressions, which often make it difficult to determine the position of
the shoreline for the moment of time investigated (see Fig. 6.11).
In spite of the difficulties encountered in geological interpretation of tsunami
deposits, such work represents the only possibility for obtaining objective data both
for tsunami zoning and for estimating distribution in space-time of the sources of
past strong tsunamigenic earthquakes.
