Calamita et al. (1994)
They study the Quaternary extensional faults of the Umbria-Marche Apennines 
Ridge and show that they cut Neogenic folds and thrusts. The faults form five 
NNW-trending, up to 30 km-long 10-15 km-apart parallel fault zones. These zones 
are from E to W: Monte Vettore-Monte Bove, Monte Fema-Norcia, Ocricchio-Monte 
Alvagnano, Cascia-Monte Boragine, and Monte Cavallo-Colfiorito. The authors 
estimate a total extension across the Cascia-Monte Vettore ENE transect of about 
2 km for the time interval Early Pleistocene-0.23 Myr. This yields an extension 
rate of about 2 mm/yr. They infer a slip rate of 1.3-1.5 mm/yr for faults 
showing maximum cumulative offset of 900-1200 m in the same interval. A similar 
slip rate is computed for faults younger than 0.23 Myr that show cumulative 
offsets of about 350 m, whereas a 1 mm/yr slip rate is calculated for the same 
faults showing 10 m-high post-Wurmian fault scarps. The authors propose a model 
with listric Quaternary normal faults that reactivate thrust. They consider the 
Ocricchio-Monte Alvagnano fault zone as related to the 1979 Norcia earthquake 
(see also IdSource180, Sant'Anatolia Source) whereas no correlation between 
other historical earthquakes and the described fault zones is suggested.

Blumetti (1995)
She reviews the historical descriptions of surface phenomena occurred in the 
Norcia-L'Aquila areas during the 1703 earthquakes sequence and compare them with 
field evidence with the aim of localising the surface ruptures related to 
seismogenic sources. The author concludes that surface ruptures are the result 
of the 14 Jan. I=IX MCS, and the 2 Feb. 1703 I=IX MCS, earthquakes. These 
ruptures occurred close to pre-existing normal faults bounding Meso-Cenozoic 
ridges that are part of a NNW-striking belt about 50 km-long and 5 km-wide, 
extending from Norcia to L'Aquila basins (see also IdSource=15, Montereale 
Source) (see also IdSource=16, Norcia Source). In particular, she infers that 
the 14 Jan. earthquake surface ruptures occurred along the eastern side of the 
Norcia basin (western branch of the Norcia Fault, west-side down) and along the 
southwestern side of the Mt. Alvagnano ridge (Alvagnano Fault, west-side down). 
The western branch of the Norcia Fault is expressed by a 20 m-high fault scarp 
that displaces a 230,000 yr paleosol. From scarp morphology the author 
hypothesises an age for this scarp younger than 100,000 yr and on this 
assumption she calculates a vertical slip rate ranging between 0.09-0.2 mm/yr. 
The ~ 0.2 mm/yr is preferred because is in agreement with that obtained from a 
100 m-high scarp along the Norcia main fault branch displacing alluvial gravel 
about 500 kyr old. In a foundation trench cut across the western branch of the 
Norcia Fault, the stratigraphic sequence exposed shows one-meter thick colluvial 
wedge. This observation is used to infer for the most recent event (the 1703 
event) a Magnitude of ~6.8 according to Wells and Coppersmith (1994) and, 
coupled with the slip rate, to infer an average recurrence time of 5000 yr. The 
author also reports that along the western branch of the Norcia Fault, and the 
Alvagnano-Castel Santa Maria Fault surface ruptures occurred during the Ms 5.9, 
19 Sep. 1979, Norcia earthquake, (see also IdSource=180, Sant'Anatolia Source).

Michetti et al. (1996)
They recognise some fault scarps bounding the western side of the Norcia basin 
and dipping to the E. They report two displaced Holocene alluvial fans that 
produce about two meters of vertical displacement of the ground. Trenches across 
these scarps at Misciano site are used to define two surface faulting events 
occurred after the deposition of an archaeological soil younger than the VIII 
century B.C.

Cello et al. (1997)
They observe that the epicentral area of the 1703 earthquake sequence coincides 
with the Norcia-L'Aquila fault set, that is the central fault set of the so-
called Central Apennines Fault System (CAFS). The CAFS is modelled by means of 
morphotectonic and structural investigations as a system of linked N-S trending 
left-lateral strike-slip faults, and from NNW to WNW-trending transtensional and 
normal faults driven by a crustal, left-lateral, N- striking shear zone. The 
Norcia-L'Aquila fault set is divided into three main N-S trending fault segments 
linked each other: the Norcia, Cittareale and L'Aquila segments. The Norcia 
fault is composed by splays that bounds both the western and eastern sides of 
the Norcia basin cutting Meso-Cenozoic bedrock and Holocene slope deposits with 
vertical movement. The authors conclude that surface ruptures from the 14 Jan. 
1703 earthquake occurred along the western side of the Norcia basin and relate 
the two meters-high Misciano scarps studied by Michetti et al. (1996) to this 
earthquake on the basis of their geomorphic evidence. At its northern and 
southern end the Norcia fault set bends to reach N-S strike joining the 
Cittareale fault set to the South. Surface ruptures from the 1703 earthquake 
sequence are reported to have occurred also along the Castel Santa Maria and 
Monte Pizzuto faults that are connected to the Cittareale fault set. The NNW-SSE 
fault bounding the eastern side of the Castel Santa Maria basin has a 7-m high 
steep scarp in bedrock and bends southward to reach a N-S strike showing a 25-m 
lateral post-Wurmian offset. From these observations the authors obtain a 0.3-
0.5 mm/yr vertical slip rate, and a 0.9-1.5 mm/yr horizontal slip rate during 
Holocene. Horizontal slip rate for a left-lateral strike-slip fault located in 
Manigi, west of Castel Santa Maria, provides similar value. 

Cello et al. (1998)
To investigate further on the tectonic behaviour of the Norcia-L'Aquila fault 
set they develop a fractal analysis providing 1.22 as fractal dimension of the 
Norcia-L'Aquila set. They infer that this is an immature fault structure growing 
by localised strain within discrete fault sets. Furthermore, re-analysing the 
trenches excavated by Michetti et al. (1996) at the Misciano site they infer two 
displacement events occurred since Roman times. Assuming one meter of slip per 
1703-type event, they  also calculate an average recurrence time of about one 
millennium. From the time elapsed since 1703 earthquake they rule out the 
possibility of generation of a comparable earthquake in a near future.

Galadini et al. (personal communication)
These workers excavated some trenches in the Castelluccio Plain, NE of Norcia 
basin. Here they find evidence for historical surface faulting but not recent enough 
to be attributed to the 1703 earthquake.
