COMMENTS

The Aspromonte Northwest Source is hypothesised to correspond to a 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 (7.2 km) is constrained by
scaling relationships of width vs. magnitude.

The 6 February 1783 earthquake occurred certainly to the south of the big shock of 5 
February, but certainly not as far south as the Messina Straits, that were largely 
unaffected except for the port of Messina and for the area around Capo Peloro. The 
accumulation of damage from the previous shock makes the assessment of the effects 
of the 6 February event more difficult, but it is clear that this was probably the 
smallest shock in the sequence (in the magnitude range 5.5 to 6.0). We hypothesise 
that this shock occurred on an inland portion of the Bagnara Calabra-Bovalino Line. 
This solution appears to be in contrast with the occurrence of a large tsunami 
following the 6 February shock, but most investigators believe that this large sea-
wave that killed hundreds of people in Scilla was in fact the result of landsliding of 
Monte Pac (at the southern end of the village) triggered by strong ground shaking. 
The expected size of the earthquake is also largely incompatible with the size and 
destructive power of the tsunami.


OPEN QUESTIONS

1) Was the tsunami that followed the 6 February 1783 shock really generated by a 
landslide? This would allow the earthquake causative fault to be located inland and 
the magnitude to be as small as suggested by the limited available historical evidence, 
probably in the range 5.5 to 6.0.

2) Is there any more specific evidence for active faulting along the Bagnara Calabra-
Bovalino Line?

3) What is the true geometry at depth of this source, and how is it linked with the 
Gioia Tauro Plain Source, which is assumed to be a pure normal fault?
