FORMER EARTHQUAKE EXPERIENCES IN CHILE.

FORMER EARTHQUAKE EXPERIENCES IN CHILE.

Within a very few months, the Pacific coast has again been visited with a most disastrous earthquake, which covered a greater extent of territory than that of San Francisco, and in loss of life and destruction of property has apparently at least rivaled, if it has not exceeded that of the northern city. In many of its features it has very much resembled the Californian visitation. Fire followed in the track and leaped beyond the limits of the earthquake and, as in San Francisco in the interference with the water mains also handicapped the firemen of Valparaiso. No sea-wave accompanied the shock, which seems to show that its centre was inland. Whether there was any connection between this earthquake and that of San Francisco can hardly be more than guessed at even by expert geologists; but the lapse of time that ensued between the two disasters and the separation of the places by several thousands of miles of strata, many of which are rarely, if ever affected by earthquakes seems.to indicate that each was separate from and independent of the other, and was due to local faults which were not in the least related. That fact, however, does not take away from another—namely,’ that a severe rupture—possibly a series of ruptures— of the strata underly-ing the earth’s surface has been going on for some considerable time—it maybe is still going on—and sooner or later may cause another earthquake elsewhere, either within the same seismic South American zone, near the centre of which Valparaiso is situated, or in some unexpected quarter elsewhere. In South America the seismic district lies between latitude 26 and 30, and has frequently been visited with destructive earthquakes, as well as sea waves along the coast. Probable the worst of these happened on August 13, 1808 By it the whole of the Pacific coast of Smith America south of Guayaquil, in Ecuador, was heavily shaken, and at Arica, in northern Chile, a vast sea wave completed the destruction wrought by the earthquake. Large vessels were washed inland nearly a mile and left high and dry far up on the mainland The details of the coast point to the weakness and the unstable equilibrium of the geological strata along that section of the Pacific coast. A few miles inland from Valparaiso Mount Aconcagua rises to a height of nearly 23,(Xto feet. A few miles off the coast the floor of the Pacific is hundreds of fathoms below the sea-level. I he coastal plain in this region is thus merely, as it were, a shelf on the steep side of a vast mountain range six or seven miles in height. An expert in seismology, writing on this subject, without insisting dogmatically on tire absolute correctness of his theory, but appealing to facts as generally bearing it out, says: “In a group of adjacent seismic regions the most unstable are those which present the strongest differences of relief. * * * The unstable regions are associated with the great lines of corrugation of the terrestial crust, either emerged or submerged. I hese variations in the confirmation of the earth’s surface are conspicuous along the land lying on the slope of the Andes toward the Pacific. The differences in height are enormous and sharp—probably more so than anywhere else in the world. Hence, probably, arises that frequent recurrence of destructive earthquakes which lias been so destructive in both Chile and Peru.

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