Great Neapolitan Earthquake of 1857/Part II. Ch. XIX

by Robert Mallet

Chapter XIX.

Sarconi.

 

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I left Moliterno at noon for Sarconi, still in heavy rain, with a cold N. E. wind. This town, a place of extreme antiquity and probably of Greek origin, is not above two Italian miles, in a right line nearly, east of the former, crossing the valley of the Sciavra. It stands on the lowest level of the piano, probably 700 feet, if not more, below Moliterno, upon the very edge of the steep and lofty bank of about 100 feet in depth, of deep alluvium and clays, overhanging the north bank of the Moglia, here in winter a large river, whose stony bed is at least 700 feet wide. It is spread out at the town upon horizontal beds of green and grey thin-bedded marls, with calcareous breccias and deep clays above. (See Geolog. section, Diagram No. 242, and Sketch, section, No. 244.)

Directly to the N. E. side of the town, a low colline of limestone rock rises to the height of about 350 feet above it, the hard and nearly horizontal beds of which, pierce up steep and abruptly through the clays, &c. This colline bears round the town a good way, east and north. (See section, Sketch No. 245.) The opposite, or right bank of the Moglia shows limestone in highly inclined beds in some places, and covered with deep alluvium.

Photog. No. 246 (Coll. Roy. Soc.) gives a good notion of the position of the town, and that No. 247, (Coll. Roy. Soc.) of the character of the horizontally bedded limestone found hereabouts, as well as that of the right bank of the Moglia. The town is situated on the tongue, between the Sciavra and the Moglia, and from the general direction of wave-path hereabouts, the blow must have been delivered to it, diagonally transverse to the tongue of land, and from the limestone masses to the east and north, and was necessarily severe. From this, from the antiquity of very many of the buildings, and their ill construction, their ruin is great. The fallen houses and hills of debris are perfectly unintelligible en masse, but two or three isolated buildings only, present fractures or fissures. These gave an average of direction, 175° E. of north, but very unsatisfactory, both from their character, and from the high wind and driving preventing good measurement.

The old church, however, gave better results. It was a building of great antiquity; the axial line was 55° W. of north, and, on entering the western door, I observed that two ancient and probably Roman altars, with nearly effaced inscriptions, had been built into the walls, and formed the pedestals for the stone jambs of the doorway. The building has wholly fallen in, and in great part the walls are down. The belfry tower stood at the north quoin (Photog. No. 248), a tower, of about 20 feet square, of which about 47 feet in height remain standing. The whole of the upper part has been thrown down, and the mass has fallen, partly within and partly without the church, and some on the highest remaining floor of the tower itself, all falling towards the S.E. There was a single bell in the tower, of about six cwt., which hung, as the "Parrochiano" (an aged priest, who politely came out in the rain to give me information, and whose name, I regret to find, I omitted to note) informed me, to a beam in the centre of the tower, and at

a height of 30 palmi above where I found it; namely, lying upon the top remaining floor, amidst rubbish and fallen timbers, with its mouth facing S. E. The centre of gravity of the bell, was 7 feet horizontally, distant from the centre of the tower, and the direction of its throw from the centre of the tower was 149° E. of north (Fig. No. 250).

This direction, I found coincided closely with that given by fissures, Photog. No. 249 (Coll. Roy. Soc.), two pairs of which gave a wave-path of 145° E. of north, and an angle of emergence from the N. W. = 16° 25′. This angle, as given by the isolated buildings before adverted to, appeared to be but 11° to 11° 30′; I rely, however, upon those of the church.

The bell had fallen vertically 30 palmi = 30 × 0.862 ft. = nearly 26 feet English. We have, therefore,

$e=16^{\circ }25'$

$a=7$

$b=26$,

and the value of

$\mathrm {V} =9.78{\mbox{ feet per second;}}$

a result necessarily below the truth, as the effort of the wave, was communicated to the bell, not through the centre of gravity, but by the pintles; so that the first effect, was merely to make it swing, contrary to the direction of throw. We may estimate the velocity as at least 2 feet per second more, or about 12 feet per second for the wave here, which, although not exact, sufficiently corroborates previous determinations.

Several very thick and very ancient walls here, built of small bad rubble, and showing themselves to have been very dead and inelastic, presented quoin fissures, open 4 1/2, 5, and even 6 1/2 inches, at 20 to 30 feet from base; the average might be taken at 4 3/4 to 5 3/4 inches, and seem to indicate a wave of long amplitude here.