EARTHQUAKE.

Dominion, Volume 2, Issue 533, 14 June 1909, Page 7

EARTHQUAKE.

SIXTY DEATHS IN FRANCE. AIX IN DARKNESS. SHIPS STRAINING AT THEIR CABLES. " MARSEILLES EXCITED. (by theoraeh—mess association—cornuoHT.) (Roc. Juno 13, 5.50 p.m.) Paris, Juno 12. Two violent shocks of earthquake havo occurred throughout tho Riviera and at Marseilles, in the south of Franco. The shocks caused great excitement in Marseilles; where the streets and cafes were thronged. : . ■ Ais, in the Department of Bouches-du-Rhono, a town of 25,000 people, 20 miles north of Marseilles, was plunged in darkness through tho failure of the electric light service." ': ' ■ . Faced with this aggravation of the peril, tho entire population of tho town remained out of doors tUI dawn. ■ Houses collapsed in. several towns in the district affected. . . Ships which wore at anchor in the port of Toulon strained at thoir cables, bo poworful was the' submarine effect of the earthquake. ' . . ; DEATH-ROLL. v; '■: '..<■'■; (Roc. June 14, 0.25 a.m.) ; '■ London, June 13. Tho earthquake in the south of Franco caused at least sixty doaUis. .-.; ,

THE TOWN OF AIX.-THE RIVIERA. ■' Aix, formerly capital of Provence,'in the dep. of Bouches-du-Ehone, is 20" milee north of Marseilles. It is believed to have been founded by the Eoman Consul, C. Sextiuß (120 8.C.), on account of the mineral springs in the neighbourhood, and thence to have got the name Aqnno Sextiae. Aix is the seat of an archbishop; and .possesses a college -with a public library of 150,000 volumes and 1100 JISS. Tho baptistery of the cathedral is believed to have been originally a .temple of Apollo. There is also an old clock tower with a quaint mechanical clock. The industry consists chiefly in cot- ' ton-spinning, leather-dressing, and trade in olive oil, wine, almonds, etc. The warm springs are slightly sulphurous, with a temperature from"9o to 100 deg. F.. The field on .which MariuS'defeated tho Teutones lies in th« plain between Aix and Aries. Population is 25,000. . LATEST THEORIES OF EARTHQUAKES. ■'■"',/ FROM LAST'TEAK'S BOOKS. : 'Two .books, amongst others, oh earthquakes were published in 1908; and the latest science on the point—aa taken from, them—was. summarised ■ ■ recently in the "Sydney Morning Herald." The books in question are: "The Physics of Earthquako Phenomena," by Professor. C.G Knott (1908); Earthquakes," by Professor W. H. Hobbs; of Michigan University (1903). , Eefcrenccs wale also taken by "Herald" from Gustave Iβ Bon's "Evolution of Forces," William Morris Bavis's "Physical •Geography," and E.' A. Proctor's "Other Suns than Ours." ■'■..■.; ' ... ■ ■ "The prime cause of earthquakes is the instability of tho earth's crust" (Knott).' Rocks a Thick Liquid. '.' Tho centre of the earth is liquid, though not tho boiling molten cauldron which it used to be thqught. The earth begins to becoiue somethins very, like a thick liquid at'six milee in depth—in this way. The rock deep in tho earth must be looked on as a pillar supporting tho weigbt'of the surface just above it. 'Eocks are . .....'a little less. than three times as heavy as ..... ■'water. At about six- milee beneath the surface tho pressure is such that all rocks known to us would be crushed by it. If wo attempted to tunnel in rock ... at this dopth tho roof of tho tunnel would immediately collapse, arid "the' opening bo entirely pealed up. The microscopic pores in the rocks would likewise bo closed. Under such conditions tho rock could never'be fractured under stress' , —any rrforo than a liquid could, which.flows into any opening as soon as it is made in it—"butwould flow much as a thick liquid" (Hobbs), Any cracks on tho surface must disappear by the time they reach this liquid, ."which has been called the zone of flow'." The'overlying zono . . .in which fractures exist ;s the "zone of fracture. ; ' ..

. It is this crust of tho earth that creases and folds; and sometimes snaps and quakes. .This crtist or zono of fraetnrc, , ' according to Hobbs, is not in the least the stiff,. strong, unsupported crnst that'it used to'be thought. It is exceedingly weak and brittle, and full of cracks and faults. It is. the thick liquid underneath, which is under the enormous pressure of the mas'! above it, which has the strength about it. The hot rocks in the intermediate zono, not quite liquid and yet not full of fissure, aro weak, ready to move under uneron pressure." . . . ; • The Folded, Rocks/ ■ ; The rocks that come molten from below, tho igneous rocks,, are quite obvious.in volcanoes and geysers, says Knott.- They are not folded rocks. 'But the sedimentary ■ rocks, like Bandstones and shale (which were a fiimplo stretch of pebble and sand laid down along the edge of a continent by the action of water and tide) . . . from the date of their deposition have sunk to form tho floor of-lakes and seas, and been raised into plateaux and mountain, masses" (Knott). .''They enter on a j , i° f , cxt ««>f<linarr vicissitudes-aro bent, doubled, folded, drawn out, snapped norosa • and tortured in all kinds of ways. They are continually, sinking : and rising in waves centuries long, like, but none the less eure, he says,, the ocean swell. And. in this bending and unbonding of the'earth's crust there are formed the folded rocksj ■' A Fracture. "If during this process fracture ocenre, immediately an earthquake shock will be transmitted through the neighbouring material." If onorock face, slips against the other a seismio disturbance will take place, which may be felt, sometimes, around tho world. In Professor Hobbs's book there is a picture of suoh a fault running across a Japaneso valley—where one-half of a plain has slipped many feet lower than the other, cutting paths and fields in half. Mountains take many ages to form in this way. But they are being formod oven,now. In William Morris Davis's book there is a photograph of certain mountains in Oregon. formed comparativclv recently. . '' : • The Ultimate Cause. ... ' / ' As to where these.forces come from which fold and unfold the earth's crust, theso very modern books do not agree. Hobbs quotes Professor milue, who has noticed that earthquakes happen when the earth's nxis swings out of its old position—which of course would cause certain strains to work -about the earth. Knott seems to think that the weight of masses of earth such as tho Himalayas (which ■ are 12 miles above the lowest ocean depths) may have something to do with it. At any rate, ho shows that tho greatest density of rock in Southern Italy and Sicily ie jnst over the<line where, this earthquake has happened. Gustavo'le Bon thinks-tha activity of some force like that of radium has something to do with earthquakes. • ' ' .

; Proctor adopts an interesting theory. He says that it has often been noticed that hurricanes, storms, depressions follow after earthquakes, and people thought the earthquakes caused them. But.-, then ■• they also •happen before earthquakes. . At. least "the earth has often been noticed dull and heavy, and : the animals aro frightened. And probably, he saj's, it is tho other way; and what caused the hurricane caused the earthquake passing of a heavy wave of air which was too heavy for tho earth's fractured surface. If the barometer rises half an inch over 10,0(10 square miles (one-sixth life size of England), those square miles, have to bear an additional weight of ■l,2C(l,000,0(iQ tons of air. If it rises nn inch, every foot- of earth bears GiiOlb.. extra, and every squaro mile 852,000 tons. Take thoso changes nlnni; a fen const, whero the heat and cold and the tides also help to increase, them, and they might well caiife a disturbance. All vocanoes, except l one in Asia, are near the sea, he fays.