The shocks were first felt in February, 1783, and continued for nearly four years. Over a very considerable area of country all the common landmarks were removed, large tracts of land were forced bodily down the slopes of mountains; and vineyards, orchards, and cornfields were transported from one site to another; insomuch that disputes afterward arose as to who was the rightful owner of the property that had thus shifted its position. Two farms near Mileto, occupying an extent of country a mile long and half a mile broad, were actually removed for a mile down the valley; and “a thatched cottage, together with large olive and mulberry trees, most of which remained erect, was carried uninjured to this extraordinary distance.” In other places the surface of the Earth heaved like the billows of a troubled sea; many houses were lifted up above the common level, while others subsided below it. Again and again the solid Crust of the Earth was rent asunder, and chasms, gorges, ravines, of various depths, were suddenly produced, in less time than it takes to tell it. Sometimes when the strain was removed, the yawning gulf as quickly closed again, and then houses, cattle, and men were swallowed up in the abyss, leaving not a trace behind. It has even been recorded—strange though it may seem—that when two shocks rapidly followed one another at the same spot, the people engulphed by the first, were again cast forth by the second, being literally disgorged alive from the jaws of death. About 40,000 persons perished in this dreadful visitation, the greater number being crushed to death beneath the ruins of the towns and villages, others swallowed up in the yawning fissures as they fled across the open country, and others again burned in the conflagrations which almost always followed the shocks of Earthquake.
Everyone has heard of the famous Earthquake of Lisbon. It is chiefly memorable for the extreme suddenness of the shock, for the immense extent of the area affected, and for the amount of havoc and destruction done. On the morning of the fatal day—it was the first of November, 1755—the sun rose bright and cheerful over the devoted city, no symptom of impending danger was visible in the sky above or on the Earth below, and the gay-hearted people were pursuing their accustomed rounds of pleasure or business, when, suddenly, at twenty minutes before ten o’clock, a sound like thunder was heard underground, the Earth was violently shaken, and in another moment, the greater part of the city was lying in ruins. Within the brief space of six minutes, 60,000 people were crushed to death. The mountains in the vicinity of the town were cleft asunder. The waters of the sea first retired from the land, and then rolled back in a huge mountain-like wave fifty feet above the level of the highest tide. A new quay, built entirely of marble, had offered a temporary place of refuge to the terrified inhabitants as they fled from the tumbling ruins of the city. Three thousand people are said to have been collected upon it, when, all at once, it sunk beneath the waves, and not a fragment of the solid masonry, not a vestige of its living freight, was ever seen again. The bottom of the sea where the quay then stood is now a hundred fathoms deep.
From Lisbon as a centre the shock of this Earthquake radiated over an area not less than four times the extent of Europe. Like a great wave it rolled northward, at the rate of twenty miles a minute, upheaving the Earth as it moved along, to the coasts of the Baltic Sea and the German Ocean. The waters of Loch Lomond, in Scotland, were violently disturbed from beneath, and at Kinsale, in Ireland, the sea rushed impetuously into the harbor without a breath of wind, and mounting over the quay, flooded the market-place. Eastward the convulsion was felt as far as the Alps, and westward it extended to the West India Islands, and even to the great lakes of Canada. On the north coast of Africa the disturbance was as violent as in Spain and Portugal; and it is recorded that at a distance of eight leagues from Morocco, the earth opened and swallowed up a considerable town with its inhabitants, to the number of eight or ten thousand people.
Even on the high seas the shock was felt no less distinctly than on dry land. “Off St. Lucar,” says Sir Charles Lyell, “the captain of the ship Nancy felt his vessel so violently shaken, that he thought she had struck the ground, but, on heaving the lead, found a great depth of water. Captain Clark, from Denia, in latitude 36° 24´ N., between nine and ten in the morning, had his ship shaken and strained as if she had struck upon a rock, so that the seams of the deck opened, and the compass was overturned in the binnacle. Another ship, forty leagues west of St. Vincent, experienced so violent a concussion, that the men were thrown a foot and a half perpendicularly up from the deck.” It is worthy of note that this, the most destructive Earthquake recorded in history, was not attended with any volcanic eruption; which goes to confirm our theory that the active Volcano serves as a kind of safety-valve for the escape of the struggling powers confined within the Crust of the Earth.[98]
We must not bring our notice of Earthquakes to an end without at least some brief account of one which has startled the world even since we began to put together the materials of this Volume. On the Western Coast of South America there is a long, narrow strip of land, lying between the lofty crests of the Andes and the shores of the Pacific Ocean, which from the earliest times has been the familiar home of Earthquakes. Toward evening on the thirteenth of August, 1868, this fated region was the scene of a convulsion the most appalling and destructive that has been recorded within the present century. The disturbance was felt in its extreme violence for a distance of 1500 miles along the coast; from Ibarra one degree north of the Equator to Iquique more than twenty degrees south. In ten minutes from the first shock, 20,000 people perished, and a vast amount of property, roughly estimated at sixty millions sterling, was utterly destroyed. Many thriving towns—Iquique, Mexillones, Pisagua, Arica, Ylo, Chala, and others—were levelled to the ground. Even the very ruins were not spared. The sea rushed in when the Earthquake shock had ceased, and carried everything before it in one universal wreck: so that in some cases not a vestige remained behind to tell the dismayed survivors where their homesteads once had stood. It might be fancied perhaps that the cities seated aloft in the security of the Eternal Hills were beyond the reach of the convulsion that shook the plain below. But no: Arequipa, far up on the slopes of the western Cordillera, and Pasco, the highest city in the world, situated on a level with the snowy summit of the Jungfrau, were shattered into fragments with the same violence as the cities of the coast.
The various incidents recorded by the survivors are full of fearful interest. At Iquique, according to one account, about five o’clock in the evening of the thirteenth of August, a rumbling noise was heard, then the earth shook violently for some minutes, then the sea, with a great moan, retired from the shore, and rearing itself up into a tremendous wave, rushed back upon the land and swept away the town. “I saw,” says one writer, “the whole surface of the sea rise as if a mountain side, actually standing up. Another shock, accompanied with a fearful roar, now took place. I called to my companions to run for their lives on to the Pampa. Too late! With a horrid crash the sea was on us, and at one sweep—one terrible sweep—dashed what was Iquique on to the Pampa. I lost my companions, and in an instant was fighting with the dark water. The mighty wave surged and roared and leaped. The cries of human beings and animals were dreadful. A mass of wreck covered me and kept me down, and I was fast drowning when the sea threw me on to a beam, but a nail piercing my coat, the timber rolled me again under, and I lost all sense. I suppose, as in all such cases, I must have struggled after sensation had left me, for when returning consciousness came I was grasping under one arm a large plank. Looking round, all was wreck and desolation. In a moment I was by a returning wave swept into the bay, and meeting a mass of broken timber, I was struck a fearful blow on the chin, and the broken end of the plank passed through my thigh. I knew no more until I found myself on the Pampa, and all dark around me. I was without trousers, coat, shoes, or hat. Trying to collect myself, I thought of another wave, and crawled away to the mountain side, scooped a hole in the ground, and got in; here, wet and shivering, I spent the night. My wound bled freely. In the morning I looked out and found Iquique gone, all but a few houses round the church.”
A good deal of shipping was lying in the bay of Arica. When the waters first receded the vessels were all carried out to sea, chains, cables, and anchors snapping asunder like packthread. A moment, afterward they were borne back irresistibly by the returning wave, and dashed to pieces on the coast. One more fortunate than the rest, the Wateree, a vessel of war belonging to the United States Government, was caught up on the crest of the wave, and with the loss of only one man, was landed high and dry among the sand-hills a quarter of a mile from the shore.
Before the Earthquake, Arequipa was a prosperous town of 30,000 inhabitants. It enjoyed a considerable trade, and, in importance as well as size, it was regarded as the third city of Peru, being inferior only to Lima and Cuzco. The houses were constructed with especial regard to security against the shock of Earthquakes. They were but one story high, built of solid stone, and massive to an extraordinary degree. But these precautions, though the fruit of long experience, were all of no avail. At Sunset on the fatal thirteenth of August the populous and thriving city of Arequipa was little better than a heap of ruins. “Not a church is left standing,” writes an eye-witness, “not a house habitable. The shock commenced at twenty minutes past five in the afternoon, and lasted six or seven minutes. The houses being solidly built and of one story, resisted for one minute, which gave the people time to rush into the middle of the streets, so that the mortality, although considerable, is not so great as might have been expected. If the Earthquake had occurred at night, few indeed would have been left to tell the story. As it is, the prisoners in the public prison, and the sick in the hospital, have perished. The Earthquake commenced with an undulating movement, and as the shock culminated, no one could keep his feet: the houses rocked as a ship in the trough of the sea, and came crumbling down. The shrieks of the women, the crash of falling masonry, the upheaving of the earth, and the clouds of blinding dust, made up a scene that cannot be described. We had nineteen minor shocks the same night, and the earth still continues in motion. Nothing has as yet been done toward disinterring the dead; but I do not think any are buried alive, as certain death must have been the fate of all those who were not able to get into the street. The earth has opened in all the plains around, and water has appeared in various places.”[99]
These are a few typical examples of the more violent convulsions by which the Crust of the Earth has been disturbed within little more than a century; and they leave no doubt as to the kind of changes which may fairly be ascribed to similar agency in the past history of the Globe. Nor must it be supposed that, because our examples are few in number, the Earthquake is itself a rare and exceptional event. On the contrary, the state of partial disturbance and convulsion would seem to be the natural and ordinary condition of our planet. From the interesting Catalogue drawn up by Mr. Mallet, it appears that, in our own times, the number of Earthquakes actually observed and recorded is, on an average, not less than from two to three every week. Now this catalogue cannot represent more than one-third of the Globe: for the disturbances which take place in the profound depths of the ocean must for the most part escape observation, and many parts even of the inhabited Earth are still beyond the reach of scientific researches. It is, therefore, quite a reasonable speculation of Sir Charles Lyell, that “scarcely a day passes without one or more shocks being experienced in some part of the Globe.”
Moreover, in Mr. Mallet’s Catalogue no account is taken of those minor vibrations or tremblings of the Earth’s Crust, which are not attended by any striking or noteworthy event. And yet such phenomena, when often repeated, may produce a very important change of level, and are far more frequent than most persons would be likely to suppose. In our quiet region of the Globe people are too apt to take for granted the general stability of the Earth: but in other countries the inhabitants, warned by long experience, are no less deeply impressed with a conviction of its instability. Sir John Herschel says that, in the volcanic regions of Central and Southern America, “the inhabitants no more think of counting Earthquake shocks, than we do of counting showers of rain:” nay, he adds that, “in some places along the coast a shower is a greater variety.” And in Sicily, we are told they make provision against movements of the Earth’s Crust, just as we make provision against lightning and storms; so much so that it is quite a common thing for architects to advertise their houses as Earth-quake-proof.