The source included in the Database is mainly based on the work of D'Addezio et al. (2001) on the Aremogna-Cinque Miglia fault. These workers found a recurrence interval in the range 2140-5080 years.
Two candidate historical earthquakes that may have been generated by this fault occurred in 801 A.D. and 1349 A.D. If none of these events ruptured this fault, and the true recurrence interval is in the lower part of the estimated range, this source could hold a significant potential for producing a large earthquake in the near future.
1) Are the Aremogna and Cinque Miglia scarps part of a single seismogenic source? Or could they behave independently?
2) When did the last surface faulting earthquake occur? In 1349 A.D., 801 A.D. or even earlier? If none of these earthquakes occurred on the Aremogna-Cinque Miglia source, could the most recent earthquake generated by this source be another known historical earthquake?
3) The 7 May 1984, Valcomino (Abruzzo) earthquake occurred on a Source very close to the Aremogna-Cinque Miglia fault. What are the spatial relationships between these sources? Is the boundary between these sources controlled by the E-W Sangro Valley Fault, proposed as the northern termination of the source by Boncio et al. (1998)?
In his review on active faults of central Italy he describes for the first time the fault scarp of the Cinque Miglia Plain as "likely active".
He describes fault scarps displacing late-glacial and post-glacial 13,000-12,000 years old deposits in the Aremogna and Cinque Miglia plains. On the basis of a detailed aerial photo and field survey he maps the fault scarps and reconstructs the stratigraphic sequence outcropping in the area. According to his mapping the scarps extend for about 10 km, with a vertical throw ranging between 0.1 and 4 m (average 1.5 m) and have a strike changing from NNW-SSE to NW-SE in the Aremogna Plain and in the Cinque Miglia Plain, respectively. Most of the scarps are west-facing, and show a uniform slope. This is interpreted as evidence of the fact that the whole fault scarp is evidence for one large earthquake occurred after 13,000-12,000 y B.P. The writer also observes that the 2000 y long historical catalogue of seismicity does not report any large local earthquake so he concludes that the recurrence time of the local surface faulting earthquakes should be longer than 2000 y.
Giraudi (1989) and Frezzotti and Giraudi (1989a; b)
These papers report on some trenches and shallow hand borings performed in the southern part of the Aremogna Plain with the aim of reconstructing the geological evolution of the Plain and to better constrain the behaviour and the age of faulting of the Aremogna faults. Only one trench was dug across the scarp, this was located at the Gravare Valley (SW side of the Aremogna Plain); here the investigators recognised one episode of faulting and dated it by means of radiocarbon dating between 12850+200 and 5060+150 y B.P. On the basis of climatic and stratigraphic considerations they narrow the time window of faulting between 7500 and 5060+150 y B.P. They propose also a preferred age of faulting: 6000 y B.P. in Giraudi (1989) and 6500-7500 y B.P. in Frezzotti and Giraudi (1989a; b).
D'Addezio et al. (2001)
By means of detailed geomorphic, microtopographic and trench investigations they analyse the seismic potential of the Aremogna-Cinque Miglia Fault. They map a 16 km-long up to 6 m-high complex fault scarp as composed of two main sections one in the Aremogna plain, the other in the Cinque Miglia plain. Both sections are formed by two sub-parallel west dipping scarps: the eastern scarp shows a typical normal fault geomorphology with a mountain range on the footwall and a basin on the hangingwall, while the western scarp produces subsidence where high mountain peaks are located and, as a consequence, causes a reversal of the present topography. Type of movement is prevalently normal although contraddictory evidence for a lateral component was found in the Aremogna area. Two trenches opened across the eastern scarp in the Aremogna Plain (trenches 1-2), a quarry exposure across the western scarp in the Cinque Miglia Plain (trench 3) and the re-interpretation of the trench data published by Frezzotti & Giraudi (1989a; b) are used to show evidence for three normal surface faulting earthquakes that were dated at: 800 B.C.-1030 A.D., 3735-2940 B.C., 3540-5000 B.C. Because part of the age interval defined for the most recent falls in the time interval covered by the historical catalogues of seismicity the authors analyse which historical events could be attributed to this fault: candidates are the 801 A.D. earthquake, which produced some damage in Rome, or even the 9 September 1349 A.D. event given the uncertainties in radiocarbon dating (the charcoal sample could be much older than the hosting deposits). The authors estimated an average recurrence interval of 2140-5080 y, a vertical Holocene slip rate of 0.1-0.5 mm/y, a 0.3-1 m slip per event and a 6.5-6.8 magnitude in the hypothesis that each of these earthquakes ruptured the entire length of the Aremogna-Cinque Miglia Fault.