COMMENTS

The Aspromonte East Source is hypothesised to correspond to a 12.5-km portion of 
the Bagnara Calabra-Bovalino Line, a rather obvious tectonic lineament that so far 
has received very little attention. This line marks the boundary between two portions 
of the Aspromonte Range: a lower (max elevation is ~ 1,000 m), more slowly 
uplifting, NNE-trending elongated section locally known as Dossone della Melia to 
the north; and a higher (~ 2,000 m), faster growing (up to 1.5 mm/y and more), rather 
circular-shaped block known as Aspromonte s.s. (or Montalto) to the south. 
The general NNE trend of local tectonic structures makes a rather sharp right turn as 
they cross the Bagnara Calabra-Bovalino Line.

The Database hypothesises that, simply based on the macro-observations described 
above, this is an active lineament characterised by oblique (normal-right lateral) 
kinematics and mirroring the Nicotera Gioiosa Ionica Line located 25 km to the 
north. The minimum depth of faulting (3 km) is set by similarity with the adjacent 
Gioia Tauro Plain Source. The maximum depth of faulting (11.3 km) is constrained by 
scaling relationships of width vs. magnitude.

The 23 October 1907 earthquake struck the Ionian coast of southern Calabria and the 
northeastern flank of Aspromonte. The distribution of damage was reported to be 
strongly biased by the precarious ground stability conditions and by the poor quality of 
buildings of Ferruzzano and other villages located to the south of the Bagnara 
Calabria-Bovalino Line. For this reason we retain a source hypothesis that is slightly 
asymmetrical (about 7 km shifted to the northeast) with respect to the epicentral 
location of the 1907 earthquake. The hypothesis of the occurrence of this earthquake 
on the southernmost reach of the Bagnara Calabra-Bovalino Line is indeed largely 
speculative; however, the occurrence of the 1894, Palmi-Bagnara and of the 1896, 
SantEufemia on the Tyrrhenian side, and of the 1889, Ferruzzano and 1896, Bianco 
events on the Ionian side in close spatial and temporal proximity with the 1907 
earthquake lends support to a nearly simultaneous activation of the entire lineament 
from coast to coast. 

Unlike the 1894 earthquake, this event did not receive much attention by 
contemporary investigators and was soon obscured  by the occurrence of the 28 
December 1908, Messina Straits earthquake. It also generated a small tsunami that was 
witnessed along the coastal stretch between Bruzzano and Bovalino, that is to say, 
symmetrical with respect to the seaward prolongation of the assumed source. 


OPEN QUESTIONS

1) If the source hypothesis is correct, was the 1907 the easternmost shock to be 
expected on the Bagnara Calabra-Bovalino Line?

2) How large was its dip-slip component?

3) What is the true geometry at depth of this source?

4) What are the geometric, spatial and dynamic relationships between the 1907 shock 
and all preceding shocks (1889, 1894, 1896), and between the 1907 shock and the large 
1908 earthquake?

