The 1887 earthquake was studies by several contemporary workers who described in 
great detail the damage associated with the event and the tsunami wave that was 
generated by the mainshock. Unfortunately, very little work exists to date on 
the causative source of this event and on it tectonic framework. For this 
reason, this review will consider also recent papers that deal  with the general 
seismotectonic setting of the western Ligurian Sea, some of which may contribute 
to a better understanding of the 1887 source. 

Fanucci et al. (1989)
These workers use selected focal mechanisms to point out the purely 
compressional nature of earthquake-related deformation in the western Ligurian 
Sea (offshore between Albenga and Nice). This evidence is found in contrast with 
available neotectonic evidence, which according to these investigators does not 
suggest the existence of significant compression. Based on a limited number of 
focal solutions, Fanucci et al. (1989) also discuss evidence for transtensional 
deformation along the Ligurian margin (that is, inland).

Ferrari (1991)
This is a comprehensive summary of all the investigations of the 1887 earthquake 
by contemporary workers and a revised list of over 1000 intensity reports. 
Ferrari (1991) locates the epicenter about 20 km offshore south of Oneglia and 
revises the magnitude up to 6.4-6.5 from the 5.6 estimate originally proposed by 
Capponi et al. (1985).

Bethoux et al. (1992)
These investigators analyse the mechanics of several shocks in the magnitude 
range 3.0 to 6.3 that occurred in the western Ligurian Sea starting with 1963. 
They conclude that all the events indicate compressional tectonics, but also 
that the stress regime is more diverse than previously thought and that the P-
axes exhibit rotations from nearly N-S to nearly E-W. The compressional regime 
is interpreted as due to lateral expulsion of the southwestern Alps along the 
Apulian indenter.

Augliera et al. (1994)
These investigators discuss the general seismotectonic framework of the Western 
Ligurian Sea combining information from background seismicity and evidence from 
reflection seismology profiles. These investigators stress the different nature 
of the onshore area, which is characterized by N120-trending reactivated 
faults, and the margin-offshore area, which is dominated by roughly N160-
trending younger faults. These offshore structures correspond to transverse 
faults perpendicular to the margin and were created during rifting of the 
Ligurian Sea. A series of sedimentary basins aligned ENE-SSW (i.e., parallel to 
the margin) and located 30-40 km from the present coast are bound by a major 
ENE-trending normal fault, but no evidence of its activity exists in the 
seismological record. In contrast, seismicity suggests compression along a 
roughly N-S trend, which is suggestive of the transpressional nature of the 
margin. According to Augliera et al. (1994), seismicity concentrates along zones 
of weakness or reactivated structures, and therefore does not appear to have a 
"primary" nature with respect to the present stress field. No specific 
interpretation is given concerning the source of the 1887 earthquake, which is 
located halfway between the coast and the system of offshore normal faults. 

Eva and Rabinovich (1997)
This paper proposes a numerical model of the tsunami associated with the 1887 
earthquake. Their best fitting model involves normal faulting along an ENE-
trending fault (south side up) located 20 to 30 km offshore in front of Imperia. 
This result is interpreted as being consistent with the postulated existence of 
a system of large normal faults located just at the foot of the continental 
margin and parallel to the coast. This system would be segmented by inferred 
transform faults perpendicular to it and to the coast.

Courboulex et al. (1998)
This paper discusses the source parameters of the 21 April 1995, Ventimiglia 
earthquake (Ml 4.7). According to these investigators, this well-recorded event 
occurred just beneath the coastline at a depth of about 9 km and had a 
dominantly reverse mechanism with a strong strike-slip component. Courboulex et 
al. discuss various lines of evidence suggesting that the event was generated by 
a compressional regime and occurred along one of a series of old NW-SE 
transverse faults that cut the Alpine margin in several narrow slices.

Gruppo di Lavoro CPTI (1999)
This catalogue revises the magnitude down to 6.3 and relocates the event on the 
coast about 5 km NE of Imperia. It should be noted, however, that the method of 
location used by CPTI tends to move towards inland the location of offshore 
earthquakes.
