Movements of the Coast and the Human Settlements
Authors: Loyda Ludvík 
Published: October 2023

In this article there are summarized the results of last investigations related to the problem of the settlements' subsiding on the seashore. Different branches of science are engaged in studying vertical movements of the shore e.g. geology, geomorphology, geodesy, oceanography, as well as history, and, as the matter now stands, each of them trying to solve the problem from its point of view. Geology and geomorphology take an interest in sudden subsidences of the coast caused by earthquakes as well as in longtimed sinking accompanied with the shifting of the coastline and with distinct changes in erosional conditions or accumulation in the coastal area. All the coasts are then classified into the raised and the subsided ones. Up to the present time the opinion is widely held that the movements of that kind may be explained by isostasy, eustasy, or generally by geological forces of endogenous origin. On the other hand the subsidence of towns seems to be caused by pumping out the underground water, by soft sediments being compressed during their consolidation, and by means of another atectonic factors. In many cases repeated geodetic levellings find out the recent subsidence of seaside towns continually increasing, but the explanation of that is by no means different from that of geology and geomorphology (fig. 2, 8, 9). The ruins of ancient towns in the area of the Mediterrannean Sea (fig. 6) have been discovered lately by sport-divers. It seems that the findings of the archaelogists together with the results of geological research will in fact enable to correct our existing opinions related to some important periods in the life of many ancient greek settlements on the coast of the Black and the Aegean Sea. The town of Chersones of Crimea has been submerged and emerged in turn many times since the 6th century B.C. The interval between its repeated subsidences is determined on about 500 years (fig. 5) and the periods of those sinkings seem to be connected closely with the epochs of well known decline of the town. Archaelogical excavations have confirmed that the town of Chersones was subjected to submergence destruction and burial under a layer of sediments at the time mentioned. In the historians' opinion, however, all the ancient greek settlements on the shore were several times living in the epoche of social decline or of ruin. It is well known today that they were overflowed by sea-water at the same time. It seems highly probable that the repeated desertion of the ancient town of Troy may also be explained in quite a similar way. There is not an ideal metod of solving the problem. It has been affirmed by geology and egomorphology that among the characteristics of the submering coasts the forming of bays, gulfs, inlets, and lagoons is of high importance. It has been proved that the origin of such a bay, etc., depends only on a subsidence of an isolated block of the earth's crust on the coast of emergence as well as on the coast of submergence which must be slowlier of course than is the velocity of the sinking block. A very long practice exists in the foundation of various types of harbours, and the gulfs and bays formed in this way were being found out always and everywhere as the best landing places for ships. By this time it has become perfectly evident that the problem of the subsiding towns and barbours may be solved successful in the way of complex investigations only. No doubt that they have to be of higher probability and correctness than the conceptions of isolated scientific branches.