Page:Great Neapolitan Earthquake of 1857.djvu/487

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Chapter XV.

Further Discussion of Observations Made at the Certosa and at Padula.


At Padula, while the main wave-path was unmistakably 17° W. of north to south, I found fissures giving extremes of directions from 155° E. of north to 166° E. of north, and evidences of a very subordinate vibration nearly from west to east. The latter, it is highly probable, was due to the partial dispersion of the main wave of shock, as it reached the southern head of the great valley, and passed from its deep formations out into the limestone mountains that shut it in to the south.

I had also evidences of such subordinate movements, and more distinctly marked, at the Certosa.

The great fissures here, by the very construction of the buildings, ran principally east and west, and north and south; the former being by much the wider (transverse to the main shock), but the abutting of the several masses of building upon each other, very generally preventing that freedom of motion, that is essential to enable deductions as to wave-path to be made thus with precision. From some of the main buildings, that rose free and unencumbered above the level of the surrounding ones, however, I obtained measures of direction, the extremes being 116° E. of north to 165° E.