In the immediate neighbourhood of the meizoseismal area, at Perrone, Pennella, and Lower Lacco, the Subsultory movement was still the more prominent; but, farther away, as at Panza, Testacchio, Barano, Ischia, and Bagno, the Subsultory motion was followed by distinctly horizontal undulations, while outside the island of Ischia only slow undulatory movements were perceptible.
"A Study of Recent Earthquakes"
Charles Davison