Part 12

=Name= =Location= =Height (feet)= =Altar= Ecuador 17,710 =Antisana= Ecuador 19,335 =Asosan= Japan 5,630 =Cayambi= Ecuador 19,255 =Chimborazo= Ecuador 21,424 =Copiapo= Chile 19,700 =Cotocachi= Ecuador 16,300 =Cotopaxi= Ecuador 18,880 =Demavend= Persia 18,500 =Etna= Sicily 9,652 =Fujiyama= Japan 12,390 =Hecla= Iceland 5,110 =Hood, Mt.= Oregon 11,225 =Iztaccihuati= Mexico 16,076 =Kirishima-yama= Japan 5,530 =Llullaillac= Chile 21,000 =Maipo= Chile 17,670 =Mauna Kea= Hawaii 13,953 =Mauna Loa= Hawaii 13,600 =Misti= Peru 20,015 =Nevado de Colima= Mexico 14,210 =Orizaba= Mexico 18,310 =Pelée= Martinique, W. I. 4,300 =Pichincha= Ecuador 15,918 =Pico, Peak of= Azores 7,013 =Popocatepetl= Mexico 17,748 =Ruiz= Colombia 17,388 =Sahama= Peru 23,000 =Sangai= Ecuador 17,459 =San Jose= Chile 20,020 =St. Elias, Mt.= Alaska 18,024 =St. Helena, Mt.= United States 10,000 =Stromboli= Lipari Islands 3,090 =Tahiti, Peak of= Friendly Islands 7,400 =Teneriffe= Canary Islands 12,000 =Tolima= Columbia 18,069 =Toluco= Mexico 14,950 =Tunguragua= Ecuador 16,690 =Vesuvius= Italy 4,260

EARTHQUAKES

Earthquakes are movements of the earth’s crust, varying in intensity from a slight tremor or shaking of the ground to the most violent convulsions causing enormous destruction over wide areas.

KINDS OF MOTION OBSERVED IN EARTHQUAKES

The wave-like or undulatory motion is most common and least destructive. It appears to be the normal one, and it is possible that the others may be simply the result of various systems of waves intersecting one another. The waves either advance in one direction, like waves of the sea, or spread from a central point, like ripples produced by dropping a pebble into still water.

The earthquakes of the Andes are chiefly linear, being propagated along the mountains, with the undulations perpendicular to the direction of the ranges. The destructive earthquake at Lisbon, was a central one, the concentric waves gradually diminishing in intensity with increasing distance from the place of origin.

The vertical motion acts from beneath like the explosion of a mine, and when violent nothing can resist its force. The earthquake at Calcutta, in September, 1828, owed its great destructiveness to the fact that the main shock was vertical; and one in Murcia, Spain, in 1829, destroyed or injured more than three thousand five hundred houses.

The rotary or whirling motion is the most dangerous, but happily the rarest of all. In the great earthquake of Jamaica, in 1692, the surface of the ground was so disturbed that fields changed places, or were found twisted into each other.

EARTHQUAKE SHOCKS AND SOUNDS

Probably no part of the earth’s surface is entirely free from vibration, but, fortunately, destructive earthquakes are confined to comparatively limited regions. In most cases each shock lasts only a few seconds, but the tremblings that follow may be continued for days, weeks, or even months. Noises of sundry kinds usually precede, accompany, or succeed an earthquake. Some earthquakes, however, are not attended by any subterranean sounds. This has been the case with some of the most destructive South American disturbances. Thus at the time of the terrible shock which destroyed Riobamba in Ecuador in 1797, a complete silence reigned. On the other hand, subterranean sounds may be heard without any earth-tremor being perceived.

The sound which accompanies many earthquakes is due to the transmission to the air of vibrations in the soil. To produce sound-waves in the air, the ground must vibrate like a drumhead. Hence no sound will be heard when the oscillations are horizontal.

The velocity of propagation of an earthquake is very variable. Thus in the case of the earthquake of Lisbon in 1755, it seems to have considerably exceeded one thousand feet per second, while in the Lisbon earthquake of 1761 the rate was three times greater. At Tokio, in 1881, the velocity, as estimated by Professor Milne, varied between four thousand feet and nine thousand feet per second.

DEPTH OF EARTHQUAKES. Various attempts have been made to estimate the depth at which earthquakes originate. Mallet was of opinion that the centrum of the Neapolitan earthquake of 1857 was probably five and one-half miles from the surface. The same eminent physicist thought that an earthquake centrum probably never exceeded a depth of thirty geographical miles. According to Professor Milne, the angles of emergence of the earth-waves obtained during the Yokohama earthquake of 1880 showed that the depth of origin of that earthquake might be between one and one-half and five miles; and he gives a table, compiled from the writings of various observers, which exhibits the mean depths at which certain earthquakes have originated. These estimated depths range from 17,260 feet to 127,309 feet.

The area disturbed by an earthquake is generally proportionate to the intensity of the shock. The great earthquake of Lisbon disturbed an area four times as great as the whole of Europe. In the form of tremors and pulsations, Mr. Milne remarks, it may have shaken the whole globe.

In a violent submarine earthquake the ordinary earth-wave and sound-wave are accompanied by sea-waves. These waves may be twenty, sixty or even eighty feet higher than the highest tide, and are usually more dreaded than the earthquake shock itself in such regions as the maritime districts of South America. The greatest sea-wave on record is that which in 1737, is said to have broken near Cape Lopatka, at the south end of Kamchatka, two hundred and ten feet in height.

=NOTABLY DESTRUCTIVE EARTHQUAKES=

79. One accompanied by the eruption of Vesuvius; the cities of Pompeii and Herculaneum buried.

742. Awful one in Syria, Palestine, and Asia; more than 500 towns were destroyed and the loss of life surpassed all calculations.

936. Constantinople overturned; all Greece shaken.

1137. Catania, in Sicily, overturned, and 15,000 persons buried in the ruins.

1186. At Calabria; one of its cities and all its inhabitants overwhelmed in the Adriatic Sea.

1456. At Naples, 40,000 persons perished.

1537. At Lisbon; 1,500 houses and 30,000 persons buried in the ruins; several neighboring towns ingulfed with their inhabitants.

1596. In Japan; several cities made ruins, and thousands perished.

1662. One in China, when 300,000 persons were buried in Pekin alone.

1693. One in Sicily, which overturned fifty-four cities and towns, and 300 villages. Of Catania and its 18,000 inhabitants not a trace remained; more than 100,000 lives were lost.

1726. Palermo nearly destroyed; 6,000 lives lost.

1731. Again in China; and 100,000 people swallowed up at Pekin.

1746. Lima and Callao demolished; 18,000 persons buried in the ruins.

1754. At Grand Cairo; half of the houses and 40,000 persons swallowed up.

1755. Quito destroyed.

1755. Great earthquake at Lisbon. In about eight minutes most of the houses and upward of 50,000 inhabitants were swallowed up, and whole streets buried. The cities of Coimbra, Oporto, and Braga suffered dreadfully, and St. Ubes was wholly overturned. In Spain, a large part of Malaga became ruins. One-half of Fez, in Morocco, was destroyed, and more than 12,000 Arabs perished there. About half of the Island of Madeira became waste; and 2,000 houses in the Island of Mytilene, in the Archipelago, were overthrown. This awful earthquake extended 5,000 miles; even to Scotland.

1759. In Syria, extended over 10,000 square miles; Baalbec destroyed.

1783. Messina and other towns in Italy and Sicily overthrown; 40,000 persons perished.

1797. The whole country between Santa Fe and Panama destroyed, including Cusco and Quito, 40,000 people buried.

1840. Awful and destructive earthquake at Mount Ararat, in one of the districts of Armenia; 3,137 houses were overthrown, and several hundred persons perished.

1842. At Cape Haytien, St. Domingo, which destroyed nearly two-thirds of the town; between 4,000 and 5,000 lives were lost.

1851. In South Italy; Melfi almost laid in ruins; 14,000 lives lost.

1852. At Philippine Isles; Manila nearly destroyed.

1853. Thebes, in Greece, nearly destroyed.

1854. St. Salvador, South America, destroyed.

1854. Amasca, in Japan, and Simoda, in Nippon, destroyed; Jeddo much injured.

1855. Broussa, in Turkey, nearly destroyed.

1857. In Calabria, Montemurro and many other towns destroyed, and about 22,000 lives lost in a few seconds.

1858. Corinth nearly destroyed.

1859. At Quito; about 5,000 persons killed, and an immense amount of property destroyed.

1868. Cities of Arequipa, Iquique, Tacna, and Chincha, and many small towns in Peru and Ecuador destroyed; about 25,000 perished.

1883. Krakatoa island, between Sumatra and Java, East Indies, was the scene of a series of volcanic discharges in May to August, 1883, constituting the most tremendous eruption known to history. A cubic mile of rock material was hurled into the air, and the explosions were heard 150 miles away. Violent atmospheric disturbances and gigantic sea-waves, the latter causing great loss of life, estimated at more than 30,000. As a result of the explosion, the north part of the island, including its highest peak, altogether disappeared.

1886. Shocks throughout eastern United States; at Charleston, S. C, 41 lives and $5,000,000 worth of property lost.

1893. Islands of Zante and Stromboli, the former west of Greece, the latter one of the Lipari group, west of Calabria, Italy, severely shaken. Great loss of lives and property at Zante.

1906. Severe shocks in California wrecked San Francisco and adjacent towns, and caused the greatest fire in history, lasting two days. Great loss of life, and $300,000,000 of property destroyed; over 300,000 homeless. Stanford University buildings were damaged to the extent of $2,800,000, including the fine Memorial Church.

1906. At Valparaiso, Chile, causing great destruction of life and property.

1907. Large part of Kingston, Jamaica, destroyed.

1909. In Sicily and southern Italy, Messina and many towns and villages desolated. Appalling loss of life; thousands buried alive; the survivors homeless; one of the greatest earthquakes of modern times if not of all time.

GEYSERS

Geysers are eruptive hot springs found chiefly in volcanic districts, but particularly in the Yellowstone Park, Iceland, New Zealand, Tibet and the Azores. At intervals these fountains of hot water and steam sometimes rise to a height of two hundred feet. The eruptions occur at intervals varying from every hour to once a day.

All the geyser waters hold in solution a considerable quantity of silica. The highly heated water decomposes the felspar and other volcanic rocks, and becoming slightly alkaline with the soda or potash these contain, it is enabled to form a silicious solution. The silica taken up is deposited again round the mouth of the orifice. Minute plants termed algæ are known to live in the hot water, and to aid in throwing down the silica from solution to form the sinter deposits.

The cause of the periodical eruptions is probably to be found in the gradual increase of heat with the depth of the tube. In the middle and lower parts the temperature is far above the boiling-point (212° F.) at the ordinary pressure. But at last the lower portion rises to a position where the temperature is above the boiling-point at the pressure it there sustains, and then, flashing into steam, it hurls the column above into the air. After playing for a few minutes the water falls back into the basin, and remains quiet for a time.

WONDERFUL GEYSERS OF THE YELLOWSTONE

The geysers of the Yellowstone region are probably the most picturesque and wonderful in the world. On the Firehole River alone there are probably fifty geysers, throwing columns of water to a height of from fifty to two hundred feet, while smaller jets rise occasionally to two hundred and fifty feet. The “Old Faithful” geyser, in this region, throws up a column of water six feet in diameter to a height of one hundred to one hundred and fifty feet, at intervals of about an hour. Near the north entrance to the National Park, also, are the hot springs of the Gardiner River; here the “White Mountain,” built up of terraces of white calcareous deposits, rises to a considerable height, with a diameter of one hundred and fifty yards at the top.

The geysers of Iceland are situated within sight of Mount Hekla and are the hottest springs in Europe. The principal geysers of this region are known as the “Great Geyser” or “Roarer,” and the “Stroker” or “Churn.”

The geysers of New Zealand attained celebrity chiefly on account of the beautiful terraces associated with them. Unfortunately, volcanic activity manifested itself throughout the region in 1886, resulting in the destruction of the terraces. The basins connected with these geysers, catching the overflow of water, are, like those of Yellowstone region, largely used by bathers, and are much resorted to by invalids.

The three localities mentioned are where geysers attain their highest development; but they also exist in many volcanic regions notably in Japan, South America, and the Malay Archipelago.

THE WATERS OF THE EARTH

Water is found in Nature in three states or conditions--as ice, vapor or steam, and as simple water. These three forms have the same chemical composition--the substance being a compound of oxygen and hydrogen, represented by the formula H₂O; but the physical condition depends entirely on its temperature. Under ordinary atmospheric conditions water is a _solid_ below 32 degrees Fahrenheit; a _gas_ above 212 degrees Fahrenheit, and a _liquid_ between these temperatures.

The purest form of water which exists in nature is rain water, though this always contains a little oxygen and carbon dioxide dissolved from the air. To obtain pure water artificially, any ordinary water is distilled, when all the solids dissolved in it are left behind. River water and spring water always contain a small quantity of solid matter, the amount and nature of the dissolved solids depending on the nature of the rocks over which the water has flowed.

Geographically it may be considered under the four heads of _springs_, _rivers_, _lakes_, and the _ocean_, which taken together forms the _hydrosphere_ of the earth.

WHERE SPRINGS HAVE THEIR SOURCE

SPRINGS, or the natural fountains of water, take their rise from reservoirs stored under ground. Water maintains a level, and hence the height to which a spring will rise depends on that of the level from which it is supplied. If the internal reservoir be on a hill, and the spring should gush out in a valley, the water may rise to a considerable height and form a natural fountain; but, on the other hand, if the reservoir be at some depth below the surface, the water may never reach the surface, and mechanical aid may be required to obtain it.

These internal reservoirs are in a great measure supplied by moisture derived from rain, snow, mist, and dew. The atmospheric water enters the earth through porous rocks, or by means of fissures, and continues to sink until arrested in its progress by rocks, such as clay, which will not permit the water to pass, or by faults which check it from spreading. The waters will then gush forth as a spring, of greater or less size, according to the supplies it may have received.

HOW MINERAL SPRINGS ARE FORMED

All springs contain a certain portion of air and gas, and also some solid matter, usually in the form of salts. When these salts are abundant, mineral springs are the result, which may be classified according to the character of their several properties, as acidulous, chalybeate, sulphurous, saline, calcareous, and silicious.

Acidulous or acid springs are those surcharged with carbonic acid gas.

Chalybeate springs are those in which iron, in the form of carbonate or sulphate, is held in solution.

Sulphur, in the form of sulphureted hydrogen or sulphate of lime, is the distinguishing ingredient in Sulphurous springs.

Saline springs are of two kinds--brine and medicinal; brine when containing a greater or less amount of chloride of sodium or common salt, and medicinal when containing other salts, as sulphate of soda, etc.

Calcareous springs are those highly charged with the salts of lime, and which have the property of petrifying substances placed within their reach, and also of depositing their contents, forming the stalactites and stalagmites of caverns, etc.

Silicious springs are so called from holding silica or flint in solution. The last-named are all hot or thermal as well as mineral springs, deriving their heat either from the natural heat of the earth at great depths, or from volcanic action. When occurring near volcanoes, they are frequently charged with bitumen, petroleum, naptha, asphaltum, etc.

WHY WATER FLOWS FROM ARTESIAN WELLS

An important class of artificial springs or wells is known as Artesian Wells. Where bent pervious beds of rock lie between two bent impervious beds, so as to make a basin-shaped depression, lower in the middle than at the edges, the rain which sinks into the pervious rock where it reaches the surface will begin to gather in the central part of the porous rock as in a reservoir.

If a hole be now bored in the hollow of the upper impervious bed till it reaches the water-bearing stratum, the water will flow out at the top. The water thus obtained may have fallen a distance of many miles several months previously, and if the gathering-ground be high the issue at the well may be forced by the pressure of the water behind to a considerable height.

FORMATION, CHARACTERISTICS AND PECULIARITIES OF RIVERS

Rivers have their sources from springs or from the melting of accumulations of snow. They do not, however, receive their largest supplies from the actual summits of mountains, for copious springs are rarely met with in such situations, nor are glaciers formed on the highest points of mountains, but more usually on slopes of the upper mountain valleys. It is, accordingly, in the latter localities that many of the largest rivers take their rise.

WATERSHED. It not unfrequently happens that several rivers take their rise in one mountain ridge, some flowing in one direction, and others taking an opposite course. Such a ridge is termed a _watershed_. Thus the Rhine, the Rhone, and the Danube all take their rise in the Alps, the first discharging itself into the North Sea, the second into the Mediterranean Sea, and the last into the Black Sea.

BASIN. The portion of country drained by a river and its tributary streams is called its _basin_, from its catching the rains which fall within its circuit, and which the river carries to the sea. The largest river-basin in Europe is that of the Volga, in Asia, that of the Ganges, in Africa that of the Nile, in North America that of the Mississippi, and in South America that of the Amazon.

=THE GREAT RIVERS OF THE WORLD=