On May 10th, 1876, a tremendous wave swept the Pacific Ocean from Peru northwards, westwards, and southwards, travelling at a rate many times greater than that of the swiftest express train. For reasons best known to themselves, writers in the newspapers have by almost common consent called this phenomenon a tidal-wave. But the tides had nothing to do with it. Unquestionably the wave resulted from the upheaval of the bed of the ocean in some part of that angle of the Pacific Ocean which is bounded by the shores of Peru and Chili. This region has long been celebrated for tremendous submarine and subterranean upheavals. The opinions of geologists and geographers have been divided as to the real origin of the disturbances by which at one time the land, at another time the sea, and at yet other times (oftener, in fact, than either of the others) both land and sea have been shaken as by some mighty imprisoned giant, struggling, like Prometheus, to cast from his limbs the mountain masses which hold them down. Some consider that the seat of the Vulcanian forces lies deep below that part of the chain of the Andes which lies at the apex of the angle just mentioned, and that the direction of their action varies according to the varying conditions under which the imprisoned gases find vent. Others consider that there are two if not several seats of subterranean activity. Yet others suppose that the real seat of disturbance lies beneath179 the ocean itself, a view which seems to find support in several phenomena of recent Peruvian earthquakes.

Although we have not full information concerning the great wave which in May, 1876, swept across the Pacific, and northwards and southwards along the shores of the two Americas, it may be interesting to consider some of the more striking features of this great disturbance of the so-called peaceful ocean, and to compare them with those which have characterized former disturbances of a similar kind. We may thus, perhaps, find some evidence by which an opinion may be formed as to the real seat of subterranean activity in this region.

At the outset it may be necessary to explain why I have asserted somewhat confidently that the tides have nothing whatever to do with this great oceanic wave. It is of course well known to every reader that the highest or spring tides occur always two or three days after new moon and after full moon, the lowest (or rather the tides having least range above and below the mean level) occurring two or three days after the first and third quarters of the lunar month. The sun and moon combine, indeed, to sway the ocean most strongly at full and new, while they pull contrariwise at the first and third quarters; but the full effect of their combined effort is only felt a few days later than when it is made, while the full effect of their opposition to each other, in diminishing the range of the oceanic oscillation, is also only felt after two or three days. Thus in May, 1876, the tidal wave had its greatest range on or about May 16, new moon occurring at half-past five on the morning of May 13; and the tidal wave had its least range on or about May 8, the moon passing her third quarter a little after eleven on the morning of May 4. Accordingly the disturbance which affected the waters of the Pacific so mightily on May 10, occurred two days after the lowest or neap tides, and five days before the highest or spring tides. Manifestly that was not a time when a tidal wave of exceptional height could be expected,180 or, indeed, could possibly occur. Such a wave as actually disturbed the Pacific on that day could not in any case have been produced by tidal action, even though the winds had assisted to their utmost, and all the circumstances which help to make high tides had combined—as the greatest proximity of moon to earth, the conjunction of moon and sun near the celestial equator, and (of course) the exact coincidence of the time of the tidal disturbance with that when the combined pull of the sun and moon is strongest. As, instead, the sun was nearly eighteen degrees from the equator, the moon more than nine, and as the moon was a full week’s motion from the part of her path where she is nearest to the earth, while, as we have seen, only two days had passed from the time of absolutely lowest tides, it will be seen how utterly unable the tidal-wave must have been on the day of the great disturbance to produce the effects presently to be described.

It may seem strange, in dealing with the case of a wave which apparently had its origin in or near Peru on May 9, to consider the behaviour of a volcano, distant 5000 miles from this region, a week before the disturbance took place. But although the coincidence may possibly have been accidental, yet in endeavouring to ascertain the true seat of disturbance we must overlook no evidence, however seemingly remote, which may throw light on that point; and as the sea-wave generated by the disturbance reached very quickly the distant region referred to, it is by no means unlikely that the subterranean excitement which the disturbance relieved may have manifested its effects beforehand at the same remote volcanic region. Be this as it may, it is certain that on May 1 the great crater of Kilauea, in the island of Hawaii, became active, and on the 4th severe shocks of earthquake were felt at the Volcano House. At three in the afternoon a jet of lava was thrown up to a height of about 100 feet, and afterwards some fifty jets came into action. Subsequently jets of steam issued along the line formed by a fissure four miles in length181 down the mountain-side. The disturbance lessened considerably on the 5th, and an observing party examined the crater. They found that a rounded hill, 700 feet in height, and 1400 feet in diameter, had been thrown up on the plain which forms the floor of the crater. Fire and scoria spouted up in various places.

Before rejecting utterly the belief that the activity thus exhibited in the Hawaii volcano had its origin in the same subterrene or submarine region as the Peruvian earthquake, we should remember that other regions scarcely less remote have been regarded as forming part of the same Vulcanian district. The violent earthquakes which occurred at New Madrid, in Missouri, in 1812, took place at the same time as the earthquake of Caraccas, the West Indian volcanoes being simultaneously active; and earthquakes had been felt in South Carolina for several months before the destruction of Caraccas and La Guayra. Now we have abundant evidence to show that the West Indian volcanoes are connected with the Peruvian and Chilian regions of Vulcanian energy, and the Chilian region is about as far from New Madrid as Arica in Peru from the Sandwich Isles.

It was not, however, until about half-past eight on the evening of May 9 that the Peruvian earthquake began. A severe shock, lasting from four to five minutes, was felt along the entire southern coast, even reaching Antofagasta. The shock was so severe that it was impossible, in many places, to stand upright. It was succeeded by several others of less intensity.

While the land was thus disturbed, the sea was observed to be gradually receding, a movement which former experiences have taught the Peruvians to regard with even more terror than the disturbance of the earth itself. The waters which had thus withdrawn, as if concentrating their energies to leap more fiercely on their prey, presently returned in a mighty wave, which swept past Callao, travelling southwards with fearful velocity, while in its train followed wave after wave, until no less than eight had taken182 their part in the work of destruction. At Mollendo the railway was torn up by the sea for a distance of 300 feet. A violent hurricane which set in afterwards from the south prevented all vessels from approaching, and unroofed most of the houses in the town. At Arica the people were busily engaged in preparing temporary fortifications to repel a threatened assault of the rebel ram Huiscar, at the moment when the roar of the earthquake was heard. The shocks here were very numerous, and caused immense damage in the town, the people flying to the Morro for safety. The sea was suddenly perceived to recede from the beach, and a wave from ten feet to fifteen feet in height rolled in upon the shore, carrying before it all that it met. Eight times was this assault of the ocean repeated. The earthquake had levelled to the ground a portion of the custom-house, the railway station, the submarine cable office, the hotel, the British Consulate, the steamship agency, and many private dwellings. Owing to the early hour of the evening, and the excitement attendant on the proposed attack of the Huiscar, every one was out and stirring; but the only loss of life which was reported was that of three little children who were overtaken by the water. The progress of the wave was only stopped at the foot of the hill on which the church stands, which point is further inland than that reached in August, 1868. Four miles of the embankment of the railway were swept away like sand before the wind. Locomotives, cars, and rails, were hurled about by the sea like so many playthings, and left in a tumbled mass of rubbish.

The account proceeds to say that the United States steamer Waters, stranded by the bore of 1868, was lifted up bodily by the wave at Arica, and floated two miles north of her former position. The reference is no doubt to the double-ender Watertree, not stranded by a bore (a term utterly inapplicable to any kind of sea-wave at Arica, where there is no large river), but carried in by the great wave which followed the earthquake of August 13. The description of the wave at Arica on that occasion should be183 compared with that of the wave of May, 1876. About twenty minutes after the first earth shock, the sea was seen to retire, as if about to leave the shores wholly dry; but presently its waters returned with tremendous force. A mighty wave, whose length seemed immeasurable, was seen advancing like a dark wall upon the unfortunate town, a large part of which was overwhelmed by it. Two ships, the Peruvian corvette America, and the American double-ender Watertree, were carried nearly half a mile to the north of Arica, beyond the railroad which runs to Tacna, and there left stranded high and dry. As the English vice-consul at Arica estimated the height of this enormous wave at fully fifty feet, it would not seem that the account of the wave of May, 1876, has been exaggerated, for a much less height is, as we have seen, attributed to it, though, as it carried the Watertree still further inland, it must have been higher. The small loss of life can be easily understood when we consider that the earthquake was not followed instantly by the sea-wave. Warned by the experience of the earthquake of 1868, which most of them must have remembered, the inhabitants sought safety on the higher grounds until the great wave and its successors had flowed in. We read that the damage done was greater than that caused by the previous calamity, the new buildings erected since 1868 being of a more costly and substantial class. Merchandise from the custom-house and stores was carried by the water to a point on the beach five miles distant.

At Iquique, in 1868, the great wave was estimated at fifty feet in height. We are told that it was black with the mud and slime of the sea bottom. “Those who witnessed its progress from the upper balconies of their houses, and presently saw its black mass rushing close beneath their feet, looked on their safety as a miracle. Many buildings were, indeed, washed away, and in the low-lying parts of the town there was a terrible loss of life.” In May, 1876, the greatest mischief at Iquique would seem to have been caused by the earthquake, not by the sea-wave, though184 this also was destructive in its own way. “Iquique,” we are told, “is in ruins. The movement was experienced there at the same time and with the same force [as at Arica]. Its duration was exactly four minutes and a third. It proceeded from the south-east, exactly from the direction of Ilaga.” The houses built of wood and cane tumbled down at the first attacks, lamps were broken, and the burning oil spread over and set fire to the ruins. Three companies of firemen, German, Italian, and Peruvian, were instantly at their posts, although it was difficult to maintain an upright position, shock following shock with dreadful rapidity. Nearly 400,000 quintals of nitrate in the stores at Iquique and the adjacent ports of Molle and Pisagua were destroyed. The British barque Caprera and a German barque sank, and all the coasting craft and small boats in the harbour were broken to pieces and drifted about in every direction.

At Chanavaya, a small town at the guano-loading dép?t known as Pabellon de Pica, only two houses were left standing out of four hundred. Here the earthquake shock was specially severe. In some places the earth opened in crevices seventeen yards deep and the whole surface of the ground was changed.

At Punta de Eobos two vessels were lost, and fourteen ships more or less damaged, by the wave. Antofagasta, Mexillones, Tocopilla, and Cobigo, on the Bolivian coast, suffered simultaneously from the earthquake and the sea-wave. The sea completely swept the business portion of Antofagasta during four hours. Here a singular phenomenon was noticed. For some time the atmosphere was illuminated with a ruddy glow. It was supposed that this light came from the volcano of San Pedro de Atacama, a few leagues inland from Antofagasta. A somewhat similar phenomenon was noticed at Tacna during the earthquake of August, 1868. About three hours after the earthquake an intensely brilliant light made its appearance above the neighbouring mountains. It lasted fully half an hour, and was ascribed to the eruption of some as yet unknown volcano.

185 As to the height of the great wave along this part of the shore-line of South America, the accounts vary. According to those which are best authenticated, it would seem as though the wave exceeded considerably in height that which flowed along the Peruvian, Bolivian, and Chilian shores in August, 1868. At Huaniles the wave was estimated at sixty feet in height, at Mexillones, where the wave, as it passed southwards, ran into Mexillones Bay, it reached a height of sixty-five feet. Two-thirds of the town were completely obliterated, wharves, railway stations, distilleries, etc., all swallowed up by the sea.

The shipping along the Peruvian and Bolivian coast suffered terribly. The list of vessels lost or badly injured at Pabellon de Pica alone, reads like the list of a fleet.

I have been particular in thus describing the effects produced by the earthquake and sea-wave on the shores of South America, in order that the reader may recognize in the disturbance produced there the real origin of the great wave which a few hours later reached the Sandwich Isles, 5000 miles away. Doubt has been entertained respecting the possibility of a wave, other than the tidal-wave, being transmitted right across the Pacific. Although in August, 1868, the course of the great wave which swept from some region near Peru, not only across the Pacific, but in all directions over the entire ocean, could be clearly traced, there were some who considered the connection between the oceanic phenomena and the Peruvian earthquake a mere coincidence. It is on this account perhaps chiefly that the evidence obtained in May, 1876, is most important. It is interesting, indeed, as showing how tremendous was the disturbance which the earth’s frame must then have undergone. It would have been possible, however, had we no other evidence, for some to have maintained that the wave which came in upon the shores of the Sandwich Isles a few hours after the earthquake and sea disturbance in South America was in reality an entirely independent phenomenon. But when we compare the events which happened in May, 1876,186 with those of August, 1868, and perceive their exact similarity, we can no longer reasonably entertain any doubt of the really stupendous fact that the throes of the earth in and near Peru are of sufficient energy to send oceanic waves right across the Pacific,—waves, too, of such enormous height at starting, that, after travelling with necessarily diminishing height the whole way to Hawaii, they still rose and fell through thirty-six feet The real significance of this amazing oceanic disturbance is exemplified by the wave circles which spread around the spot where a stone has fallen into a smooth lake. We know how, as the circles widen, the height of the wave grows less and less, until, at no great distance from the centre of disturbance, the wave can no longer be discerned, so slight is the slope of its advancing and following faces. How tremendous, then, must have been the upheaval of the bed of ocean by which wave-circles were sent across the Pacific, retaining, after travelling 5000 miles from the centre of disturbance, the height of a two-storied house! In 1868, indeed, we know that the wave travelled very much further, reaching the shores of Japan, of New Zealand, and of Australia, even if it did not make its way through the East Indian Archipelago to the Indian Ocean, as some observations seem to show. Although no news has been received which would justify us in believing that the wave of May, 1876, produced corresponding effects at such great distances from the centre of disturbance, it must be remembered that the dimensions of the wave when it reached the Sandwich Isles fell far short of those of the great wave of August 13–14, 1868.

It will be well to make a direct comparison between the waves of May, 1876, and August, 1868, in this respect, as also with regard to the rate at which they would seem to have traversed the distance between Peru and Hawaii. On this last point, however, it must be noted that we cannot form an exact opinion until we have ascertained the real region of Vulcanian disturbance on each occasion. It is possible that a careful comparison of times, and of the direction in which the wave front advanced upon different shores, might serve187 to show where this region lay. I should not be greatly surprised to learn that it was far from the continent of South America.

The great wave reached the Sandwich Isles between four and five on the morning of May 10, corresponding to about five hours later of Peruvian time. An oscillation only was first observed at Hilo, on the east coast of the great southern island of Hawaii, the wave itself not reaching the village till about a quarter before five. The greatest difference between the crest and trough of the wave was found to be thirty-six feet here; but at the opposite side of the island, in Kealakekua Bay (where Captain Cook was killed), amounted only to thirty feet. In other places the difference was much less, being in some only three feet, a circumstance doubtless due to interference, waves which have reached the same spot along different courses chancing so to arrive that the crest of one corresponded with the trough of the other, so that the resulting wave was only the difference of the two. We must explain, however, in the same way, the highest waves of thirty-six to forty feet, which were doubtless due to similar interference, crest agreeing with crest and trough with trough, so that the resulting wave was the sum of the two which had been divided, and had reached the same spot along different courses. It would follow that the higher of the two waves was about twenty-one feet high, the lower about eighteen feet high; but as some height would be lost in the encounter with the shore-line, wherever it lay, on which the waves divided, we may fairly assume that in the open ocean, before reaching the Sandwich group, the wave had a height of nearly thirty feet from trough to crest. We read, in accordance with this explanation, that “the regurgitations of the sea were violent and complex, and continued through the day.”

The wave, regarded as a whole, seems to have reached all the islands at the same time. Since this has not been contradicted by later accounts, we are compelled to conclude that the wave reached the group with its front parallel to the188 length of the group, so that it must have come (arriving as it did from the side towards which Hilo lies) from the north-east It was, then, not the direct wave from Peru, but the wave reflected from the shores of California, which produced the most marked effects. We can understand well, this being so, that the regurgitations of the sea were complex. Any one who has watched the inflow of waves on a beach so lying within an angle of the line that while one set of waves comes straight in from the sea, another thwart set comes from the shore forming the other side of the angle, wil............