Earthquakes and volcanos proceed from the same common cause—Recent earthquakes in New Zealand—Vast tracts of land permanently upraised—Earthquakes of Chili in the present century—Crust of the Earth elevated—Earthquake of Cutch in India, 1819—Remarkable instance of subsidence and upheaval—Earthquake of Calabria, 1783—Earthquake of Lisbon, 1755—Great destruction of life and property—Earthquake of Peru, August, 1868—General scene of ruin and devastation—Great sea wave—A ship with all her crew carried a quarter of a mile inland—Frequency of earthquakes.

The chief effect of volcanic eruptions on the Geological structure of our Globe consists in the accumulation of cinders and molten rock, either upon the Surface of the Earth, or in the crevices and caverns that abound within its solid Crust. Sometimes, indeed, the operations of an active Volcano are accompanied by a movement of upheaval or of subsidence. Thus for instance, we have seen that a portion of the Italian coast was elevated when Monte Nuovo was thrown up, that the town of Tomboro was submerged on the occasion of the eruption of Sumbawa, and that the bottom of the sea was notably upheaved by the last outbreak of the volcanic fires of Santorini. Nevertheless it appears to be generally the case that when the Crust of the Earth is once burst open, and a means of escape thus afforded to the fiery agent below,—in other words, when the active volcano is established,—the process of upheaval gives place to that of eruption. But when, as is often the case, no such safety-valve is offered to the surplus energies of the subterranean fires, then the giant power of heat, in its struggle to escape, shakes the foundation of the hills, and uplifts the superincumbent mass of solid rocks.

This theory which ascribes the phenomena of Earthquakes and Volcanos to the same common cause, acting under different circumstances, is now almost universally adopted by Geologists; and it may be briefly enforced by the following considerations. First, though Earthquakes have sometimes occurred far away from any known volcanic region, yet they are more frequent in the neighborhood of active or extinct Volcanos. Secondly, almost all volcanic eruptions are preceded by Earthquakes; and the Earthquakes generally cease, or, at least become less violent, when the subterranean fire breaks out in the form of a Volcano. And, Thirdly, it is plain that the condensed steam which is generated by internal heat, and the expansive power of the heat itself, must, of necessity, when pent up in the caverns of the Earth, tend to produce those very phenomena by which Earthquakes are distinguished.

Let it be observed, however, that while we explain the phenomena in question by the agency of subterranean heat, this doctrine is by no means necessary for the main purpose of our present argument. Whatever may be the cause from which the Earthquake shock proceeds, it is enough for us to show that the Crust of the Earth has been from time to time upraised, and dislocated, and rent asunder in modern times, just as it is supposed in Geological theory, to have been upraised, and dislocated, and rent asunder from time to time in by-gone ages. We will set down a few out of the many examples observed and recorded during the last hundred and twenty years.

When the English colonists settled in New Zealand, about fifty years ago, they were told by the natives that they might expect a great Earthquake every seven years. This alarming prediction has not been literally fulfilled; but it is fully admitted that the total number of such disturbances within the last half century has not fallen short of what it should have been according to the above estimate. During the years 1826 and 1827 several shocks were felt in the neighborhood of Cook Strait, after which it was observed that the sea-shore had been uplifted on the north side of Dusky Bay. So transformed was the outline of the coast that its former features could no longer be recognized; and a small cove called the Jail, which had previously afforded a commodious harbor to vessels, engaged in seal fishing, was completely dried up.

But the most memorable convulsion took place on the night of January the twenty-third, 1855. A tract of land, about as large as Yorkshire, on the southwest coast of the North Island, was permanently upraised from one to nine feet. The harbor of Port Nicholson, together with the valley of the Hutt, was elevated four to five feet; and a sunken rock, regarded before as dangerous to navigators, has remained since the Earthquake three feet above the level of the water. The shock was felt by ships at sea a hundred and fifty miles from the coast; and it is estimated that the whole area affected was not less than three times the extent of the British Islands.

The whole coast of Chili has been subject to great disturbances and changes of level during the present century. In November, 1837, the town of Valdivia was destroyed by an Earthquake, and at the same moment, a whaling vessel, a short distance out at sea, was violently shaken, and lost her masts. The bottom of the sea was afterward found to have been raised in some places more than eight feet; and several rocks appeared high above the water which had previously been covered at all times by the sea. Two years before, in 1835, the town of Conception and several others were reduced to ruins by a like visitation. After the first great convulsion the Earth remained for many days in a state of commotion. More than three hundred lesser shocks were counted from the twentieth of February to the fourth of March. On this occasion, too, the bed of the sea was upheaved; and the whole island of Santa Maria, seven miles in length, was lifted up from eight to ten feet above its former level.

The Earthquake of 1822 was more violent, perhaps, and more striking in its effects, than either of those just mentioned. On the nineteenth of November in that year a sudden convulsive shock was simultaneously felt over a space 1200 miles in length. At Valparaiso, and on either side for a considerable distance, the coast was permanently upheaved. When Mrs. Graham, who was then living on the spot, and who has left us an account of the Earthquake, went down to the shore on the following day, she “found the ancient bed of the sea laid bare and dry, with beds of oysters, mussels, and other shells adhering to the rocks on which they grew, the fish being all dead, and exhaling most offensive effluvia.” Some idea may be formed of the gigantic power here in operation, when it is remembered that to uplift the coast of Chili, it was necessary to move the mighty chain of the Andes, and, amongst the rest, the colossal mass of Aconcagua, 24,000 feet in height. How far this process of upheaval extended out to sea, beneath the bed of the ocean, has not been accurately ascertained: but certain it is that, for a considerable distance, the soundings were found to be shallower than before the Earthquake. It is roughly estimated that the Crust of the Earth was elevated over an extent of 100,000 square miles, or about half the area of France.

On the western coast of India, near the mouth of the river Indus, is the well-known district of Cutch. In the month of June, 1819, this extensive territory, not less than half the size of Ireland, was violently shaken by an Earthquake, several hundred people were killed, and many towns and villages were laid in ruins. The shocks continued for some days, and ceased only when the outburst of a Volcano seemed to open a vent for the troubled spirit within. But what is particularly worthy of note is that when the Earthquake had passed away, a permanent change was found to have been effected in the level of the surrounding country. The town and fort of Sindree, situated on the eastern arm of the Indus, together with a tract of land 2,000 square miles in extent, were submerged beneath the waters. The principal buildings, however, still remained standing, with their upper parts above the surface; and many of the inhabitants, who had taken refuge in one of the towers attached to the fort, were saved in boats when the Earthquake had ceased. On the other hand, within five miles and a half of this very spot, the level surface of the Earth was upheaved, so as to form a long elevated bank, fifty miles in length and sixteen in breadth, which has been called the Ullah Bund, or the Mound of God. Nine years after this event, Sir Alexander Burnes went out in a boat to the ruins of Sindree, and standing on the summit of the tower, which still rose two or three feet above the surface of the water, he could see nothing around him but a wide expanse of sea, save where a blue streak of land on the edge of the horizon marked the outline of the Ullah Bund. Here was a striking illustration, on a small scale, of those changes which Geologists suppose to have been going on since the world first began; the dry land had been converted into the bed of the sea, and the level plain had been elevated into a mountain ridge.

Toward the close of the last century the province of Calabria, in Southern Italy, was the scene of an Earthquake which offers a very apposite illustration of our present argument. This celebrated convulsion is not, however, chiefly remarkable for its violence, or for its duration, or for the extent of the territory moved. In all these respects it has been surpassed by many Earthquakes, experienced in other countries, within the last hundred and fifty years. But the Calabrian Earthquake has an especial claim on our attention, mainly from this unusual circumstance, that the region of disturbance was visited, as Sir Charles Lyell tells us, “both during and after the convulsions, by men possessing sufficient leisure, zeal, and scientific information, to enable them to collect and describe with accuracy such physical facts as throw light on geological questions.”

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.