Page:Great Neapolitan Earthquake of 1857 Vol 2.djvu/158

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REFLECTED WAVES AND EARTHQUAKE ECHO.
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mean of several sets gives a wave-path 45° 30' E. of north, from the S.W. The emergence still is apparently very small, not above 3° or 4° here, or, therefore possibly, horizontal. The whole north side, has been thrown outwards, and the foil indicates the wave-path also towards the N.E.

The smallness of the angle of emergence, I can now see from the highest points of the town, has arisen from its isolated blocks having oscillated separately, and confounded the emergence due to the wave with their own line of oscillation, which was approximately horizontal.

I remark from this point, also, that the mass of the south flank and shoulder of Vulture, lies right in the line of wave-path from the town, which, isolated as its blocks are, may be viewed, as placed upon a free lying surface, in the direction of the wave transit. The Piano della Croce, and other hills to the north and east, must also have sent back reflected waves, and a direct earthquake echo.

The Chiesa Madre was completely demolished in 1851, except one Capella and the Campanile. These show by the old crevasses, that the wave-path was then south to north. They afford no indications as to the recent one.

A very heavy wall (Photog. No. 331, p. 7) adjoining a vault beneath some large building, close to the west of the Chiesa Madre, is far out of plumb, twisted and thrown to the south and west, but still standing. It has been a little supported by a bank of earth to the southward of it, which at the end still remaining nearly plumb, reached to about one-third its height from the base; but the other end, that in front of the photograph, was unsupported.

The precise direction of wave-path cannot be calculated,