Page:Great Neapolitan Earthquake of 1857 Vol 2.djvu/350

Rh observed at Ottajano, will be referred to hereafter. The small spread of the isoseismal of Naples (—····—····—) to the north, between Frigento and Monte Freddano, &c., is due to the extremely broken, irregular, and hummocky nature of the mountains, about these spaces and down to Pagano, as well as to the obstructive effects of the transverse north and south ridges, in producing earthquake shadow, as already explained.