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CHAPTER III.

THE TERRIBLE PHENOMENA OF EARTHQUAKES.

Nature's Destructive Agencies—Tremendous Forces Pent up Within the Earth

Frequency of Earthquake Shocks-A Country in South America Never QuietSigns of the Approaching Disaster-A Part of our own Country Sunk by a Convulsion-The Great Earthquake of Calabria-Human Beings Tossed in the Air–Heavy Objects Whirling About-Farms Changing Places-Jamaica Visited -Destruction of the City of Lisbon-The Sea Rushing Madly on the ShureTerrible Loss of Life-Horrors Multiplied - Immense Fissures in the EarthGreat Calamity at Messina-Statistics Showing Appalling Destruction of Lise - Charleston in Terror-Java and Southern Europe Shaken.

ARTHQUAKES are the most fearful, and at the same time the most destructive, phenomena of nature. They are motions produced on the earth's solid surface by a force originating in

the interior of the globe, and thence acting upward. This force appears to be subject to great variations in its intensity. In most cases the commotions occasioned by it on the earth's surface are exceedingly slight. The motion is scarcely felt, and passes away in the same moment. The larger number of earthquakes consist of a slight trembling of the ground, which can only be perceived by attentive observation, and then only under very favorable circumstances. When they have passed away, it is impossible to discover the slightest traces of their transitory activity. But at other times they are attended with effects so terrible and destructive, that no other calamity can be compared with them. When the subterraneous force to which they owe their origin acts with a violent degree of energy, it produces such convulsions on the earth's surface, that not only are the works destroyed that men have raised to render their lives comfortable, and the buildings levelled to the ground that they have erected to protect them against the inclemency of the seasons, but in some cases the face of the country is changed that has been subjected to their operation. It is happily the case that earthquakes attended with such fearful effects are not of frequent occurrence; they would otherwise render the countries visited by them uninhabitable for man and beast.

Frequency of Earthquakes. In countries frequently subject to earthquakes, only those convulsions which are attended by destructive consequences are remembered by the inhabitants for any long time after. The slight ones are hardly noticed, or are only recorded by some curious observer. It appears, therefore, to persons living at a great distance from such places, and receiving information of them only when producing some great calamity, that earthquakes are not frequent, and occur only at periods remote from each other. This, however, is an error. Earthquakes are very frequent. By an exact observer not less than fifty-seven earthquakes have been noticed within the space of forty years in the town of Palermo, in Sicily, which were attended by such smart shocks as to be sensibly felt.

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EFFECT OF AN EARTHQUAKE ON THE SEA. In the town of Copiapo, in the extreme northern province of Chile, one or more shocks are felt almost every day; and though they commonly pass off without causing any damage, the town has suffered by them so frequently, and so many lives have been lost by the downfall of buildings, that the inhabitants rush out of their houses as soon as the least commotion of the earth is perceived. If it were possible, says Humboldt, to obtain daily information respecting the state of the whole surface of our globe, we probably should convince ourselves that this surface is nearly always shaken at some point or other, and that it is subject to an uninterrupted reaction between the interior and the exterior.

Signs of Coming Destruction. Many persons are apt to suppose that those countries which are situated in the vicinity of active volcanoes are more frequently subject to violent concussions than those which lie at greater distances from them. This opinion is not correct; but it is true that carthquakes are common in the neighborhood of volcanoes. Every eruption of the mountain, and even every new flow of lava, or every ejection of ashes, is accompanied by a shock, which, however, is so slight, that it can only be perceived by persons who are near the crater, or on the declivities of the volcano. These slight shocks can hardly be considered as earthquakes, as they are not felt in the plain at its base. But many eruptions are preceded by real earthquakes. When the inhabitants of a country surrounding an active volcano observe that the mountain has ceased to emit smoke from its crater, they consider it as a sign of an approaching earthquake, and in many cases their fear has not proved unfounded. It may be true that earthquakes are most frequent in countries lying in the vicinity of a volcano; but few of the more disastrous convulsions of this description have occurred in such localities. The greater number have happened at considerable distances from any active volcano, and even from places which by the nature of the rocks show that they have once been the seat of volcanic activity. It is also observed that earthquakes occurring at no great distance from volcanoes are of comparatively short duration, whilst the convulsions visiting countries lying far from them are repeated almost daily for months together, and frequently several times in one day. Of such a description were the earthquakes which were experienced during more than a whole year (1812) in the plains of the Mississippi, and those which shook, in 1808, the Alpine valleys lying at the base of Mount Cenis.

A Country Sunk by a Convulsion. That part of the plain of the Mississippi River, which, in 1812, experienced a great number of strong concussions, and those repeated for several months together, extends between New Madrid, on the Mississippi, to the Little Prairie, north of Cincinnati. The principal seat of the earthquake was consequently nearly equi-distant from the Gulf of Mexico and from the Atlantic Ocean. The following particulars respecting this earthquake are from Sir Charles Lyell: Flint, the geographer, who visited the country seven years after the event, informs us that a tract of many miles in extent, near the Little Prairie, became covered with water three or four feet deep; and when the water disappeared a stratum of sand was left in its place. Large lakes, of twenty miles in extent, were formed in the course of an hour, and others were drained. The graveyard at New Madrid was precipitated into the bed of the Mississippi ; and it is stated that the ground whereon the town is built, and the river bank for fifteen miles above, sank eight feet below their former level. The neighboring forest presented for some years afterwards a singular scene of confusion; the trees standing inclined in every direction, and many having their trunks and branches broken.

The inhabitants relate that the earth rose in great undulations; and when these reached a certain fearful height, the soil burst, and vast volumes of water, sand, and pit coal were discharged as high as the tops of the trees. Flint saw hundreds of these deep chasms remaining in an alluvial soil, seven years after. The people in the country, although inexperienced in such convulsions, had remarked that the chasms in the earth were in a direction from S. W. to N. E.; and they accordingly felled the tallest trees, and laying them at right angles to the chasms, stationed themselves upon them. By this invention, when chasms opened more than once under these trees, several persons were prevented from being swallowed up. At one period during this earthquake, the ground not far below New Madrid swelled up so as to arrest the Mississippi in its course, and to cause a temporary reflux of its waves. The motion of some of the shocks is described as having been horizontal, and of others perpendicular ; and the vertical movement is said to have been much less desolating than the horizontal.

Human Beings Hurled Through Space. The upheaving shocks are accompanied by violent upliftings of the earth, as if repeated explosions were exerting their force upon the roof of a hollow cavern, threatening to burst open the ground and blow into the air every thing placed on it. They may also be compared to the bursting of a mine, which explodes with great force and removes the earth which it meets within its passage. When the surface of the earth is split by them, it is hardly to be conceived what terrible destruction must be produced in a few minutes by such convulsions following each other in quick succession. There are numerous instances on record which prove the immense force with which these shocks act on the surface and on everything on it; some of them, indeed, appear almost incredible. In the great earthquake of Calabria, 1873, the most elevated portion of the granite mountain mass of the Aspromonte was seen to move up and down rapidly; persons were raised from the ground and thrown to a distance from the place where they were; houses were removed from their site and carried to places higher than those on which they had been built. The foundation of many buildings was removed from beneath the ground with such violence, that the stones were broken to pieces and scattered about, and the hard cement which had united them was crushed into dust. After the great earthquake of Riobama, in 1797, on the table land of Quito, the corpses of several of the inhabitants of the town were found on the top of a hill, separated from the place by a river, and several hundred feet higher than the site of the town. These persons had been hurled to the top of the hill by the violent upheavings of the ground.

The rotatory shocks are certainly the most destructive, but are those also which occur most rarely. They have only been observed in the most calamitous earthquakes, and not in all of them. The whirling motion puts the surface of the earth into a movement resembling that of che sea when agitated by irregular waves crossing and repulsing each other in different directions. In the earthquake of Catania, in Sicily, in 1818, many statues were turned round, and a large piece of rock had its former position from south to north changed to that of east to west. Several instances of this kind were observed after the great earthquake of Valparaiso, in Chili, when that town was levelled to the ground. The large church La Merced presented the most remarkable ruin. The tower was built of bricks and mortar, and its walls up to the belfry were six feet thick. They were shivered into blocks, and thrown to the ground. On each side of the church were a number of square buttresses of good solid brick work, six feet square. Those on the western side were all thrown down, as were all but two on the eastern side; these two were twisted from the wall in a north-easterly direction, each presenting an angle to the wall. The twisting to the north-east was noticed in several other places. In a village thirty miles north of Valparaiso, the largest and heaviest pieces of furniture were turned in the same direction.

Singular Confusion Caused by the Moving of the Ground. In some instances it has been found that large pieces of ground had exchanged their respective situations. This was the case at several places in Calabria, after the first great shock had passed by. A plantation of mulberry trees had been carried into the middle of a cornfield, and left standing there; and a piece of ground sown with lupines had been forced into a vineyard. For several years after the earthquake, lawsuits were brought in the courts of Naples to decide the claims which had originated in the confusion of territorial possessions by the effects of that terrible

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