The San Francisco calamity by earthquake and fire Part 28

Fujiyama is almost a perfect cone, with, as above said, a truncated top, in which is the crater. It is, however, less steep than Mayon. Its upper part is comparatively steep, even to thirty-five degrees, but below this portion the inclination gradually lessens, till its elegant outlines are lost in the plain from which it rises. The curves of the sides depend partly on the nature, size and shape of the ejected material, the fine uniform pieces remaining on comparatively steep slopes, while the larger and rounder ones roll farther down, resting on the inclination that afterward becomes curved from the subsidence of the central ma.s.s.

The most recent and one of the most destructive of volcanic eruptions recorded in j.a.pan was that of Bandaisan or Baldaisan. For ages this mountain had been peaceful, and there was scarcely an indication of its volcanic character or of the terrific forces which lay dormant deep within its heart. On its flanks lay some small deposits of scoriae, indications of far-past eruptions, and there were some hot springs at its base, while steam arose from a fissure. Yet there was nothing to warn the people of the vicinity that deadly peril lay under their feet.

BANDAISAN'S WORK OF TERROR

This sense of security was fatally dissipated on a day in July, 1888, when the mountain suddenly broke into eruption and flung 1,600 million cubic yards of its summit material so high into the air that many of the falling fragments, in their fall, struck the ground with such velocity as to be buried far out of sight. The steam and dust were driven to a height of 13,000 feet, where they spread into a canopy of much greater elevation, causing pitchy darkness beneath. There were from fifteen to twenty violent explosions, and a great landslide devastated about thirty square miles and buried many villages in the Nagase Valley.

Mr. Norman, a traveler who visited the spot shortly afterward, thus describes the scene of ruin. After a journey through the forests which clothed the slopes of the volcanic mountain and prevented any distant view, the travelers at last found themselves "standing upon the ragged edge of what was left of the mountain of Bandaisan, after two-thirds of it, including, of course, the summit, had been literally blown away and spread over the face of the country.

"The original cone of the mountain," he continues, "had been truncated at an acute angle to its axis. From our very feet a precipitous mud slope falls away for half a mile or more till it reaches the level. At our right, still below us, rises a mud wall a mile long, also sloping down to the level, and behind it is evidently the crater; but before us, for five miles in a straight line, and on each side nearly as far, is a sea of congealed mud, broken up into ripples and waves and great billows, and bearing upon its bosom a thousand huge boulders, weighing hundreds of tons apiece."

On reaching the crater he found it to resemble a gigantic cauldron, fully a mile in width, and enclosed with precipitous walls of indurated mud. From several orifices volumes of steam rose into the air, and when the vapor cleared away for a moment glimpses of a ma.s.s of boiling mud were obtained. Before the eruption the mountain top had terminated in three peaks. Of these the highest had an elevation of about 5,800 feet.

The peak destroyed was the middle one, which was rather smaller than the other two.

"The explosion was caused by steam; there was neither fire nor lava of any kind. It was, in fact, nothing more nor less than a gigantic boiler explosion. The whole top and one side of s...o...b..ndai-san had been blown into the air in a lateral direction, and the earth of the mountain was converted by the escaping steam, at the moment of the explosion, into boiling mud, part of which was projected into the air to fall at a long distance, and then take the form of an overflowing river, which rushed with vast rapidity and covered the country to a depth of from 20 to 150 feet. Thirty square miles of country were thus devastated."

In the devastated lowlands and buried villages below and on the slopes of the mountain many lives were lost. From the survivors Mr. Norman gathered some information, enabling him to describe the main features of the catastrophe. We append a brief outline of his narrative:

MR. NORMAN'S NARRATIVE

"At a few minutes past 8 o'clock in the morning a frightful noise was heard by the inhabitants of a village ten miles distant from the crater.

Some of them instinctively took to flight, but before they could run much more than a hundred yards the light of day was suddenly changed into a darkness more intense than that of midnight; a shower of blinding hot ashes and sand poured down upon them; the ground was shaken with earthquakes, and explosion followed explosion, the last being the most violent of all. Many fugitives, as well as people in the houses, were overwhelmed by the deluge of mud, none of the fugitives, when overtaken by death, being more than two hundred yards from the village." From the statements made by those fortunate enough to escape with their lives, and from a personal examination of the ground, Mr. Norman inferred that the mud must have been flung fully six miles through the air and then have poured in a torrent along the ground for four miles further. All this was done in less than five minutes, so that "millions of tons of boiling mud were hurled over the country at the rate of two miles a minute."

The velocity of the mud torrent may perhaps be overestimated, but in its awful suddenness this catastrophe was evidently one with few equals. The cone destroyed may have been largely composed of rather fine ashes and scoriae, which was almost instantaneously converted into mud by the condensing steam and the boiling water ejected. The quant.i.ty of water thus discharged must have been enormous.

Of the remaining volcanic regions of the Pacific, the New Zealand islands present some of the most striking examples of activity. All the central parts, indeed, of the northern island of the group are of a highly volcanic character. There is here a mountain named Tongariro, on whose snow-clad summit is a deep crater, from which volcanic vapors are seen to issue, and which exhibits other indications of having been in a state of greater activity at a not very remote period of time. There is also, at no great distance from this mountain, a region containing numerous funnel-shaped chasms, emitting hot water, or steam, or sulphurous vapors, or boiling mud. The earthquakes in New Zealand had probably their origin in this volcanic focus.

THE NEW ZEALAND VOLCANOES

Tongariro has a height of about 6,500 feet, while Egmont, 8,270 feet in height, is a perfect cone with a perpetual cap of snow. There are many other volcanic mountains, and also great numbers of mud volcanoes, hot springs and geysers. It is for the latter that the island is best known to geologists. Their waters are at or near the boiling point and contain silica in abundance.

At a place called Rotomahana, in the vicinity of Mount Tarawera, there was formerly a lake of about one hundred and twenty acres in area, which was in its way one of the most remarkable bodies of water upon the earth. Formerly, we say, for this lake no longer exists, it having been destroyed by the very forces to which it owed its fame. Its waters were maintained nearly at the boiling point by the continual accession of boiling water from numerous springs. The most abundant of those sources was situated at the height of about 100 feet above the level of the lake. It kept continually filled an oval basin about 250 feet in circ.u.mference--the margins of which were fringed all round with beautiful pure white stalact.i.tes, formed by deposits of silica, with which the hot water was strongly impregnated. At various stages below the princ.i.p.al spring were several others, that contributed to feed the lake at the bottom, in the centre of which was a small island. Minute bubbles continually escaped from the surface of the water with a hissing sound, and the sand all round the lake was at a high temperature. If a stick was thrust into it, very hot vapors would ascend from the hole.

Not far from this lake were several small basins filled with tepid water, which was very clear, and of a blue color.

The conditions here were of a kind with those to which are due the great geysers of Iceland and the Yellowstone Park, but different in the fact that instead of being intermittent and throwing up jets at intervals, the springs allowed the water to flow from them in a continuous stream.

THE PINK AND WHITE TERRACES

The silicious incrustations left by the overflow from the large pool had made a series of terraces, two to six feet high, with the appearance of being hewn from white or pink marble; each of the basins containing a similar azure water. These terraces covered an area of about three acres, and looked like a series of cataracts changed into stone, each edge being fringed with a festoon of delicate stalact.i.tes. The water contained about eighty-five per cent. of silica, with one or two per cent of iron alumina, and a little alkali.

There were no more beautiful products of nature upon the earth than those "pink and white terraces," as they were called. The hot springs of the Yellowstone have produced formations resembling them, but not their equal in fairy-like charm. One series of these terraced pools and cascades was of the purest white tint, the other of the most delicate pink, the waters topping over the edge of each pool and falling in a miniature cascade to the one next below, thus keeping the edges built up by a continual renewal of the silicious incrustation. But all their beauty could not save them from utter and irremediable destruction by the forces below the earth's surface.

On June 9, 1886, a great volcanic disturbance began in the Auckland Lake region with a tremendous earthquake, followed during the night by many others. At seven the next morning a lead-covered cloud of pumice sand, advancing from the south, burst and discharged showers of fine dust.

The range of Mount Tarawera seemed to be in full volcanic activity, including some craters supposed to be extinct, and embracing an area of one hundred and twenty miles by twenty.

The showers of dust were so thick as to turn day into night for nearly two days. Some lives were lost, and several villages were destroyed, these being covered ten feet deep with ashes, dust and clayey mud. The volcanic phenomena were of the most violent character, and the whole island appears to have been more or less convulsed. Mount Tarawera is said to be five hundred feet higher than before the eruption; glowing ma.s.ses were thrown up into the air, and tongues of fiery hue, gases or illuminated vapors, five hundred feet wide, towered up one thousand feet high. The mountain was 2,700 feet in height.

TARAWERA IN ERUPTION

This eruption presented a spectacle of rarely-equalled grandeur.

To travelers and strangers the greatest resultant loss will be the destruction of those world-famous curiosities, the white and pink terraces, in the vicinity of Lake Rotomahana and the region of the famous geysers. The natives have a superst.i.tion that the eruption of the extinct Tarawera was caused by the profanation of foreign footsteps. It was to them a sacred place, and its crater a repository for their dead.

The first earthquake occurred in this region. One side of the mountain fell in, and then the eruption began. The basin of the lake was broken up and disappeared, but again reappeared as a boiling mud cauldron; craters burst out in various places, and the beautiful terraces were no more. After the first day the violence gradually diminished, and in a week had ceased. Very possibly another lake will be formed, and in time other terraces; but it is hardly within the range of probability that the beauty of the lost terraces will ever be paralleled.

In this eruption, as usual, we find the earthquake preceding the volcanic outburst. New Zealand, like the Philippines, Java and the j.a.panese Islands, is situated over a great earth-fissure or line of weakness. Subsidence or dislocation from tensile strain of the crust took place, and the influx of water to new regions of heated strata may have developed the explosive force. The earthquake and the volcano worked together here, as they frequently do, unfortunately in this case destroying one of the most beautiful scenes on the surface of the globe.

THE ANTARCTIC VOLCANOES

Much further south, on the frozen sh.o.r.e of Victoria Land in the Antarctic regions, Sir James Ross, in 1841, sailing in his discovery s.h.i.+ps the Erebus and Terror, discovered two great volcanic mountains, which he named after those two vessels. Mount Erebus is continually covered, from top to bottom, with snow and glaciers. The mountain is about 12,000 feet high, and although the snow reaches to the very edge of the crater, there rise continually from the summit immense volumes of volcanic fumes, illuminated by the glare of glowing lava beneath them.

The vapors ascend to an estimated height of 2,200 feet above the top of the mountain.

CHAPTER XXV.

The Wonderful Hawaiian Craters and Kilauea's Lake of Fire.

In the central region of the North Pacific Ocean lies the archipelago formerly known as the Sandwich Islands, now collectively designated as Hawaii. The people of the United States should be specially interested in this island group, for it has become one of our possessions, an outlying Territory of our growing Republic, and in making it part of our national domain we have not alone extended our dominion far over the seas, but have added to the many marvels of nature within our land one of the chief wonders of the world, the stupendous Hawaiian volcanoes, before whose grandeur many of more ancient fame sink into insignificance.

THE ISLAND OF HAWAII

The Island of Hawaii, the princ.i.p.al island of the group, we may safely say contains the most enormous volcano of the earth. Indeed, the whole island, which is 4000 square miles in extent, may be regarded as of volcanic origin. It contains four volcanic mountains--Kohola, Hualalia, Mauna Kea and Mauna Loa. The two last named are the chief, the former being 13,800 feet, the latter 13,600 feet, above the sea-level. Although their height is so vast, the ascent to their summits is so gradual that their circ.u.mference at the base is enormous. The bulk of each of them is reckoned to be equal to two and a half times that of Etna. Some of the streams of lava which have emanated from them are twenty-six miles in length by two miles in breadth.

On the adjoining island of Maui is a still larger volcano, the mighty Haleakala, long since extinct, but memorable as possessing the most stupendous crater on the face of the earth. The mountain itself is over 10,000 feet high, and forms a great dome-like ma.s.s of 90 miles circ.u.mference at base. The crater on its summit has a length of 7 1/2 and a width of 2 1/4 miles, with a total area of about sixteen square miles. The only approach in dimensions to this enormous opening exists in the still living crater of Kilauea, on the flank of Mauna Loa.

A VOLCANIC ISLAND GROUP

The peaks named are the most apparent remnants of a world-rending volcanic activity in the remote past, by whose force this whole Hawaiian island group was lifted up from the depths of the ocean, here descending some three and a half miles below the surface level. The coral reefs which abound around the islands are of comparatively recent formation, and rest upon a substratum of lava probably ages older, which forms the base of the archipelago. The islands are volcanic peaks and ridges that have been pushed up above the surrounding seas by the profound action of the interior forces of the earth.

It must not be supposed that this action was a violent perpendicular thrust upward over a very limited locality, for the mountains continue to slope at about the same angle under the sea and for great distances on every side, so that the islands are really the crests of an extensive elevation, estimated to cover an area of about 2000 miles in one direction by 150 or 200 miles in the other. The process was probably a gradual one of up-building, by means of which the sea receded as the land steadily rose. Some idea of the mighty forces that have been at work beneath the sea and above it can be gained by considering the enormous ma.s.s of material now above the sea-level. Thus, the bulk of the island of Hawaii, the largest of the group, has been estimated by the Hawaiian Surveyor General as containing 3,600 cubic miles of lava rock above sea-level. Taking the area of England at 50,000 square miles, this ma.s.s of volcanic matter would cover that entire country to a depth of 274 feet. We must remember, however, that what is above sea-level is only a small fraction of the total amount, since it sweeps down below the waves hundreds of miles on every side.

CRATER OF HALEAKALA