108 CHARLES DAVISON 
fracture separated by a distance of from 2 to 50 or more yards. 
The most destructive effects of the earthquake are concentrated 
along this fracture, starting from Passopomo, through Linera, to 
beyond Mortara. Here the railway line was seriously damaged, 
the rails being displaced and contorted. The fracture can be 
followed as far as the seacoast, bending slightly to the south in 
the neighborhood of Sta. Tecla. Almost throughout the fractured 
zone there is a change of level, in some places of only an inch or 
two in others of 15 or 16 inches, and in one, near the seacoast, of 
more than 3 feet, the ground of the southwest side being left at 
a higher level than that on the northwest side.t The fracture is 
by no means a recent one, for it has been known since 1879, and 
Professor Platania states that displacements have occurred along 
it in previous earthquakes. Nor is it the only fracture along which 
movements have taken place during this series of earthquakes. 
There is a second at Fiandaca (No. 2), which was observed during 
the earthquakes of 1894 and 1907, and which probably corresponds 
with another at Fossalacqua (No. 3). Near this fracture occurred 
the greatest damage wrought by the two strong fore-shocks of 
May 7. 
During the interval covered by this series of earthquakes 
there was a marked increase in the activity of Etna, though the 
different shocks were not coincident with the volcanic explosions. 
Perimeiric earthquakes.—On September 10, 1911, a great eruption 
of Etna began, and, notwithstanding the extraordinary energy of 
the early phenomena, ceased after only thirteen days of activity. 
Three weeks later occurred the destructive Fondo Macchia earth- 
quake of October 15, t911. ‘This earthquake was, however, pre- 
ceded by at least 1o fore-shocks, the first 5 of which occurred on 
September 30 at Pisano (intensity 7, Mercalli scale), October 9 
(2 shocks) at Piano d’Api (intensity 5), and October 14 at S. 
Venerina (intensity 6). The principal shock (intensity 10) occurred 
at 9:52 A.M. on October 15, and was followed by 4 slight after- 
shocks on October 24 and 1 on November 9. 
‘There is also some evidence of horizontal displacement. A high wall in the 
upper part of the fractured zone is curved and shifted toward the southeast. 
