CASE STUDIES AND IMPLICATIONS ON LONG ...

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Journal of Earthquake Engineering, Vol. 5, No. 1 (2001) 35–68 c Imperial College Press

ARCHAEOSEISMOLOGY IN ITALY: CASE STUDIES AND IMPLICATIONS ON LONG-TERM SEISMICITY

FABRIZIO GALADINI CNR, Instituto di Ricerca sulla Tettonica Recente, via del Fosso del Cavaliere, 00133, Roma, Italy E-mail : [email protected] PAOLO GALLI Servizio Sismico Nazionale, via Curtatone, 3, 00185, Roma, Italy E-mail : [email protected] Received 3 March 1999 Revised 27 March 2000 Accepted 4 April 2000 Four Italian cases from central Apennines and central-eastern Alps show how the use of archaeoseismology and paleoseismological investigations on deformed archaeological remains may improve the knowledge on long-term seismicity. In the Fucino Plain (central Apennines), the displacement of a Roman canal (built during the 1st–2nd century AD) was caused by the movement of one of the active faults affecting the basin. The paleoseismological analysis and available archaeological data permitted to date the event at the 5th–6th century AD and to hypothesise that this earthquake was also responsible for significant damage to the Colosseum in Rome shortly before 508 AD. At the Egna site (Bolzano province, northern Italy), the displacement of a Roman building has been paleoseismologically investigated. It probably resulted from surface faulting, thus permitting to hypothesise the occurrence of strong earthquakes in an area for which seismicity does not show significant historical earthquakes. In the Sulmona Plain (central Apennines) the occurrence of a strong event around the middle of the 2nd century AD is testified by an epigraph. Widespread evidence of building, collapses and abandonments characterise a number of archaeologically investigated sites and confirm the age of occurrence inferred from the epigraph. In the Trento area (northern Italy), evidence of earthquake-induced damage to medieval buildings suggests that the earthquake which affected northern Italy in 1117 may have been responsible for significant damage also in the Adige Valley. Gained experience indicates that in areas where historical research does not contribute significantly to the knowledge of the effects of strong earthquakes, the use of archaeological evidence of past earthquakes may be a valuable tool to obtain information on the historical seismicity related to moderate–large magnitude events.

1. Introduction Italian seismic catalogues provide information on the seismicity over a long time span (about 2500 years in Boschi et al. [1995]). However they are not complete (also in the case of large magnitude events, M ≥ 6) prior to 1200–1300 AD and the effects of some strong earthquakes occurred in the earliest centuries of the second millennium AD are poorly known. 35


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F. Galadini & P. Galli

Archaeoseismology and the application of paleoseismological techniques to deformed archaeological remains may significantly improve the knowledge of large and moderate magnitude seismicity. The collection of archaeoseismological evidence spread over a region allows to hypothesise the damage pattern related to an ancient earthquake. In the case of tectonically-induced displacement of archaeological remains, paleoseismological techniques may provide further information on the characteristics of the deformation and on the fault behaviour. Notably, archaeological data (obtained through the application of modern stratigraphic criteria) permit in each case to relate an event to a very short time interval, thus reducing the uncertainties resulting from the classical dating methods that are usually used in the paleoseismological analysis. However, in many cases uncertainties affect the attribution of archaeologicallyinferred evidence of destruction to specific natural causes. Therefore further information is generally needed, such as paleoseismological, geotechnical and historical data. This paper addresses these issues through the review of four different case studies investigated in Northern and Central Italy (Fig. 1), from the evident case of coseismic deformation of a Roman canal (Fucino Plain) to the case of the probable coseismic destruction of churches which may confirm the evidence derived from the poor historical sources (Trento area).

Fig. 1. Location of the investigated sites: (1) Fucino Plain, (2) Egna archaeological site, (3) Sulmona Plain, (4) Trento area.


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The first two case studies (Fucino Plain and Egna site) have already been the object of past publications (Galadini and Galli, [1996] and [1999]; Galadini et al. [1997a]). Therefore only an updated review of the available data is proposed. In particular, new chronological data (radiocarbon and archaeological dates) are presented to better constrain the age of the seismic event in the Fucino Plain. Each case has some implications for the improvement of the knowledge of the regional seismicity and related seismotectonic aspects. These implications will be discussed in specific sections. 2. The Fucino Plain 2.1. Paleoseismology applied to deformed archaeological remains in the Fucino Plain The Fucino Plain is the largest fault-bounded intermontane basin of the central Apennines (Fig. 2). The area was struck by a destructive earthquake in 1915 (Ms = 7, according to Margottini et al. [1993]) responsible for surface faulting (Galadini et al. [1997b] and references therein). The Fucino basin was a lake until the 19th century, when it was drained for agricultural purposes. A previous attempt to drain the lake had already been made by the Romans in the 1st–2nd century AD, by digging a tunnel through Mt. Salviano and some open canals necessary to drain the water towards the tunnel [Brisse and

Fig. 2. Map of the Fucino basin showing site locations and the surface faulting pattern of the 1915 earthquake inferred from Galadini et al. [1997b]: MHF, Marsicana Highway Fault; SBGF, San Benedetto dei Marsi – Gioia dei Marsi Fault; TF, Trasacco Fault; LMF, Luco dei Marsi Fault.


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De Rotrou, [1883]; Fig. 2]. It is unfortunately unknown when the operation of the Roman drainage works ceased, due to the scarcity of historical information. Although the main drainage canal is completely filled by more recent lacustrine deposits, its faint trace is still visible on aerial photographs and Giraudi [1988] observed that it crosses one of the active fault branches of the Fucino area (Trasacco fault, TF in Fig. 2). Excavations made at this interception (site 1 in Fig. 2) showed that the canal and its fill deposits are displaced by the fault (Fig. 3). The younger sediments affected by the displacement (unit C in Fig. 3) deposited during the earliest lacustrine phase after the Roman hydraulic works ceased to function (Galadini and Galli, [1996]). Displacements are sealed by the youngest lacustrine sediments (unit E in Fig. 3) which deposited just before the final drainage of the lake in the 19th century (Galadini and Galli [1996]) and therefore are the result of an earthquake which occurred before the 1915 one and after the 1st–2nd century AD (age of the Roman hydraulic works in the Fucino basin). Radiocarbon dating of the displaced sediments did not permit to better constrain the chronological interval in which the seismic event occurred. Due to probable isotope fractionation (already described for other lacustrine deposits in central Italy, e.g. Branca et al. [1989]), dates for unit B in Fig. 3 are 3490 ± 70 BP and 3390 ± 70 BP, which are obviously not representative of the true age of sediments filling a Roman canal. 2.2. Chronological constraints for the displacement event The pre-1915 displacement event has been recognised also in a trench excavated on the eastern side of the basin (site 2 in Fig. 2). At this location, a peat level affected by this event yielded a radiocarbon date of 426–782 AD (cal. age). According to Galadini and Galli [1996] the displacement occurred during the peat deposition and therefore around the 5th–8th century AD. The peat represents the first evidence of the “new” high standing lake level after the Roman drainage and on this basis the displacement event is assumed to have occurred immediately after the end of operation of the Roman hydraulic works (Galadini and Galli [1996]). Due to the lack of further chronological constraints, however, the authors considered that the end of operation of the hydraulic works occurred presumably during the decadence of the Roman empire and therefore the earliest part of the above-reported chronological interval was preferred as a possible age of the displacement event. New archaeological data and radiocarbon dates permit to better define when the Roman hydraulic works ceased to function and hence the age of the seismic event responsible for the investigated displacements. On the northern portion of the basin, a long trench excavated (during 1998) for the laying of a gas pipeline crossed another paleo-canal [site 3, Fig. 2 and Fig. 4(a)] filled with organic silts, rich of pottery shards of age older than the 5th–6th century AD (R. Cairoli, pers. comm.). This canal was part of the Roman hydraulic network controlling the water flow through the basin. A sample collected in the lowest portion of the fill succession gave a radiocarbon age of 135–340 AD (cal. age),

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Fig. 3. Geological cross-sections of the SW wall of the transversal trench (a) and the SE wall of the longitudinal trench (b) excavated inside the main Roman channel at site 1 (Fig. 2 for location). Units A, B and C are the displaced channel fill. Sediments D consist of unstructured yellowish sandy silts that likely resulted from strong weathering due to the roots of dry-land or water plants. Observed displacements are sealed by unit E (from Galadini and Galli [1996], modif.).

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Fig. 4. (a) View of the trench excavated for the laying of a gas-pipeline; arrows highlight the bottom of a Roman canal at site 3 (Fig. 2); darkish deposits represent the channel fill; the calibrated radiocarbon date is related to the lower portion of the fill sediments; (b) view of the archaeological excavation at site 4.

showing that the hydraulic works started to loose their operation at least since the 4th century AD. Recent archaeological excavations performed at site 4 (Fig. 2) uncovered the remains of a mill [Fig. 4(b)]. The mill was built on the lacustrine sediments deposited just before the Roman drainage (dated at 50 BC–70 AD, 14C cal. age), and is located along the shoreline related to the natural lake level of the latest centuries prior to the 18th century drainage. Samples of the wooden portions of the mill gave radiocarbon dates of 370–425 AD and 245–410 AD (14C cal. ages). At this site only pottery shards of the 5th–6th century AD were found (R. Cairoli, pers. comm.), along with the calcareous blocks from a previous villa of the Roman imperial age and reused in the building of the mill. These data indicate that the mill was probably built close to the 5th century AD. The lack of more recent pottery limits the period of use of the mill to the above mentioned 5th–6th century AD. The archaeological excavation also brought to light the canal which permitted the drainage of the water towards the mill. A sample collected from the upper portion of the lacustrine succession filling the canal gave a radiocarbon age of 556–688 AD (cal. age), indicating that before this date lacustrine deposition began to affect the


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site area. Therefore, the abandonment of the mill shortly after its building was probably due to the ingression of the lake. Data collected at site 3 indicate that the Roman hydraulic works began to cease operation in the 4th century AD, while data collected at site 4 indicate that the lake ingression at sites located along the natural shoreline related to the “undrained” lake occurred in the 5th–6th century AD. Taking into account that the age of the event responsible for the displacement of the Roman canal is close to the age of the lake ingression at sites located along the “natural” shoreline, we can assume that the event occurred about the 5th–6th century AD. 2.3. Other archaeological evidence of the pre-1915 earthquake in the Fucino area The most significant evidence was reported by Mertens [1969; 1989] and is related to the results of archaeological excavations in the old town of Alba Fucens (Fig. 2). A destruction horizon was found and related to an earthquake by the author. After the catastrophic event some provisional huts were built and fragments of marble sculptures were commonly used to obtain lime mortar. Among the remains buried by the ruins two coins appear to be significant, the first relating to Constans II (346–361 AD) and the second to Valens (364–367 AD). Coins of this period were used until the 7th century (e.g. Reece [1984]; Molinari [1994]) and therefore they suggest that the event occurred between the half of the 4th and the 7th century AD, consistently with the other chronological data available. 2.4. Damaging earthquakes in Rome According to the seismic catalogues (e.g. Molin et al. [1995]) many earthquakes have affected Rome during its long history, and some were strongly felt. Significant damage in Rome was due to the 801, 1349, 1703, 1812 and 1915 earthquakes (e.g. Molin et al. [1995]). Other events were responsible for damage before that of 801 AD, but information on these earthquakes is very poor and the epicentral areas are unknown. Among the above mentioned events, only the 1812 event originated in the southern Rome area, the other representing the largest magnitude earthquakes originated in the central Apennines (Fig. 5). Of the ones reported above, the 1703 and the 1349 events were responsible for further damage to the Colosseum (e.g. Molin et al. [1995] and references therein). 2.5. The 508 AD Rome earthquake Considering that strong earthquakes in the central Apennines are responsible for significant damage in Rome, the interest for the 508 AD earthquake (actually the earthquake occurred slightly before this date) has recently increased owing to direct evidence of damage to the Colosseum. Ongoing collaboration with archaeologists


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Fig. 5. Epicentral distances from Rome for earthquakes with I ≥ 6/7 MCS (in Rome). Intensities are taken from Molin et al. [1995] and Boschi et al. [1997].

Fig. 6. Memorial stones located at the northern entry of the Colosseum in Rome which relate to the restorations of the Colosseum after an “abominandi terraemotus” (frightful earthquake).

working at different sites in Rome is aimed at searching for other possible traces of this earthquake. The effects of the earthquake may be inferred from two epigraphs at the Colosseum in Rome (Fig. 6) recalling significant restorations to the monument due to seismic damage. According to these epigraphs, the restorations had been carried out under Decius Marius Venantius Basilius and due to the lack of an unequivocal date of his consulate, the earthquake was tentatively related to a time shortly before 484 AD or 508 AD (Boschi et al. [1995]; Molin et al. [1995]).


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Recent excavations in the Colosseum highlighted that the event occurred closer to the latter date (Rea [1993] and pers. comm.).

2.6. Implications In the present case two independent archaeological pieces of evidence of earthquake occurrence are available in different places: the epigraph in Rome and the displaced Roman canal in the Fucino Plain. The former is chronologically well constrained and indicates a damaging seismic event occurred shortly before 508 AD. In contrast, chronological data gathered at the site of the Roman canal only permitted to assume that a strong earthquake occurred after the 2nd century AD and before the 1915 one. Further geological and archaeological investigations presented in this paper allow to better constrain the chronology of this event and to relate it to the 5th– 6th century AD. Considering the relation between earthquake-induced damage in Rome and large magnitude events in the central Apennines (Fig. 5), we suggest that the event which affected Rome shortly before 508 AD may have originated in the Fucino Plain. Should this be the case, it would be related to the activation of the same seismogenic structure responsible for the 1915 event and the time interval between the last two events responsible for surface faulting in the Fucino Plain would be slightly longer than 1407 years.

3. The Egna Site 3.1. Archaeological excavations at Egna The archaeological site is located inside the village of Egna (about 30 km North of Trento, in the Adige valley; Fig. 7) on the distal portion of a large alluvial fan. Archaeologists discovered the ruins of a Roman building (1st century AD) under 0.6–1.5 m of recent alluvial fan deposits. The building consisted of several rooms and a large courtyard; the whole structure is 30 × 25 m large. Remains are represented by portions of walls (only few tens of centimetres high), their foundations and parts of mortar floor. All the walls are 45 cm thick, resting on a 70 cm thick and 80–90 cm deep foundation and are made of rounded and subangular pebbles of sandstones and porphyrities. A destruction level, represented by wood/charcoal and bone fragments, embricated tiles and pottery shards, covers the walls. The walls are affected by approximately N–S fractures that displaced the structure both vertically and horizontally (Fig. 8). Considering the southeasternmost shear plane, the courtyard floor and the top of the foundation are vertically displaced by 50–60 cm while the northern wall is left-laterally displaced by about 20 cm (Fig. 9). The mortar floor is lowered by 34 cm towards SE due to the shear planes affecting the NW corner of the structure (Galadini et al., [1997a]; Galadini and Galli [1999]).


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Fig. 7. Seismotectonic map of the Adige Valley area. Earthquakes of the 1000–1980 period are taken from Camassi and Stucchi [1997], while events of the 1982–1997 period are taken from instrumental recordings of the Trentino-Alto Adige seismic network of the Trento Province. Focal mechanisms are taken from Slejko et al. [1989]. Capital letters indicate specific fault names: C, Cortaccia thrust; VN, Val di Non structures; M. Molveno thrust; PZ, Paganella-Zambana thrust; BS, Mt. Baldo-Mt. Stivo thrust (from Galadini and Galli [1999], modif.).


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Fig. 8. Plan map of the Egna archaeological site. The traces of the shear planes affecting the walls of the Roman building are shown along with the seven trenches (light grey) excavated (from Galadini and Galli [1999], modif.)

Fig. 9. View of trench 2 (see Fig. 8 for location). Note the lowering and the dextral displacement of the foundation base on the left side of the photograph.


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Seven trenches were excavated in 1996 across the shear planes (Fig. 8), inside the courtyard and adjacent to the displaced walls (Galadini and Galli [1999]), which made it possible to analyse the displacements affecting the fan deposits below the Roman building (see for example the log of the deepest trench reported in Fig. 10). 3.2. Chronological constraints for the displacement of the Roman walls Archaeological data indicate that the building was constructed during the 1st century AD (Dal Ri and Zangirolami [1985]). This age is consistent with the radiocarbon dating (10–130 AD, cal. age) of a wood fragment (part of the building). Archaeological findings in the stratigraphic unit sealing the displacements and the ruins suggest that the destruction occurred around the middle of the 3rd century AD (Galadini et al. [1997a]; Galadini and Galli [1999]). This unit also represents a level of reutilization of the area, before the progressive alluvial fan deposition and burial of the site by more than 1 m of sands and gravels. This depositional phase was responsible for erasing surface evidence of the most recent displacement, throughout the entire alluvial fan where the archaeological site is located. 3.3. The cause of the displacement Landsliding does not appear among the possible causes of the displacement, since the site area is almost completely flat and far from the hillslope. The hillslope itself does not show any evidence of landslides or deep-seated gravitational movements whose age may be comparable with that of the Roman building. Strong alluvial events of the Adige river may have been responsible for undercutting in the area and triggering landsliding along the river bank. However, evidence of such paroxistic events is lacking in other outcrops investigated in the area between the archaeological site and the Adige river. In contrast, there is clear evidence of deposition in an environment characterised by calm river waters. Stratigraphic data from trenches and four boreholes (dug up to 20 m) show the lack of clayey levels or peats which may have caused differential settlements. Moreover, the sand levels whose liquefaction may have caused the deformations are not thick enough to justify the observed displacements. Hence, the displacement of the Roman walls and the destruction of the building may be related to a seismic event occurred around the middle of the 3rd century AD and the shear planes may represent the surficial expression of an active fault. In this case the peculiar geological evolution of the area (recent alluvial fan deposition) should be responsible for hiding all possible surficial evidence of the recent tectonic activity. Moreover the location of the archaeological site inside a town makes it impossible to perform further excavations. Therefore, although the Egna case is another example of displaced archaeological remain, it is quite different from that studied in the Fucino Plain, where a fault trace is clearly recognisable in the field.

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(a) Log of trench 6 (northern wall); (b) stratigraphic setting of the archaeological site.


Fig. 10.

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Fig. 11. History of ancient settlements in the Trentino-Alto Adige region, reconstructed by means of the available archaeological data. Numbers refer to the site locations reported in Fig. 7. A clustering of abandonment, destruction or rebuilding during the middle of the 3rd century is visible. This evidence of crisis in the investigated region is traditionally related to the Aleman invasions (from Galadini and Galli [1999], modif.).

The seismic assumption may be supported by further archaeological data derived from other sites in the investigated region. Figure 11 highlights the history of ancient settlements, showing building or rebuilding and destruction or abandonment phases. Destruction events occurred in the same period may suggest general and ubiquituous crises (invasions or natural catastrophes). A general crisis seems to affect the investigated sites around the middle of the 3rd century AD. However, this crisis is traditionally attributed to the Aleman invasions occurred after 258 AD, even if historical documents about invasion episodes in the Adige region are lacking (Christlein [1979]).


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3.4. Implications The seismicity in the Adige region (North of Verona) is mostly related to the Giudicarie and Mt. Pasubio structural domains, respectively West and East of the Adige River Valley (Fig. 7). The magnitude of the most significant historical earthquakes is, however, lower than 6 (e.g. Camassi and Stucchi [1997]). Only the 1117 earthquake is reported as a large magnitude event, but its epicentral area is not precisely known (see Sec. 5.4 in this paper), even if it is presently located in the Verona area. The evolution of the Adige region is strongly influenced by the morphogenic processes related to the last glacial maximum and subsequent fluvial regime. For this reason, Quaternary deposits of preglacial age are quite scarce and it is usually difficult to perform studies on the recent tectonic evolution. However, evidence of recent tectonics has been reported in a number of works mainly related to the Lake Garda area (being part of the Giudicarie domain) and to the SW sector of the Lessini Mts. (Baroni [1985]; Carton and Castaldini [1987]; Castaldini et al. [1988]; Cavallin et al. [1988a]; Castellaccio and Zorzin [1996]). North of Trento, the seismicity strongly decreases and no significant earthquakes are known. However, structures of the Giudicarie fault system also affect this region with some evidence (though not conclusive) of recent activity (e.g. Zanferrari et al. [1982]; Cavallin et al. [1988b]). Therefore, understanding whether significant earthquakes may occur also in this area is one of the main problems involved in the study of the seismotectonics in the Adige region. As for the Egna site, the trend of the shear planes affecting the Roman building is consistent with the general trend of the faults affecting the carbonate bedrock on both flanks of the Adige Valley in the investigated area (part of the Giudicarie fault system). The structure affecting the archaeological site resembles a negative flower-like structure related to strike-slip movements. The trend of the investigated shear planes is parallel to that of the so-called North Giudicarie Line, the major structural (basically transpressional) feature affecting this Alpine sector. The recent study by Prosser [1998] has highlighted a complex kinematic history of this important fault system, through dextral transpression (late Oligocene-early Miocene) until the most recent sinistral transpressional phase (middle-late Miocene). The occurrence of strain partition during this phase is indicated by compression along the North Giudicarie Line and pure left-lateral movements along the vertical N–S faults affecting the footwall of the Giudicarie thrust. As for the present strain regime, few focal mechanisms are available and only for the southern portion of the Giudicarie system (Fig. 7), confirming reverse and strike-slip faulting (both dextral and sinistral for about N–S trending fault planes). Therefore, if available kinematic data highlight significant strike-slip components along the Giudicarie system, on the other hand the pre-Quaternary age of the deformations indicated by paleotectonic studies and the few data related to the present kinematic regime (inferred from focal mechanisms) prevent the possibility to compare the local deformation observed at the Egna site with the poorly known present regional kinematic characteristics.


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In short, the Egna case adds to the little evidence of recent tectonics in the Adige region and the discovery of the displaced walls at the archaeological site indicates the possible occurrence of significant earthquakes also in the region north of Trento, where evidence of strong seismicity is presently lacking. Due to the peculiar geological characteristics of the Alpine regions, studies on the seismotectonic and seismic hazard perspectives are always problematic. The results obtained show that in such regions the integration of archaeology and investigations on fault activity may contribute significantly to this kind of studies. 4. The Sulmona Plain 4.1. The Mt. Morrone fault The Sulmona Plain is bordered to the East by a 20-km-long NW–SE trending fault (Mt. Morrone Fault) which is highlighted by bedrock (carbonate) fault scarps. The fault zone is made of two parallel branches affecting the lower and upper portions of the western slope of Mt. Morrone. Fault planes are usually exposed along the scarps and place the carbonate bedrock in contact with late Pleistocene slope deposits which are displaced along the fault (Figs. 12 and 13). From a stratigraphic point of view, these deposits result from the last significant depositional episode along the central Apennine mountain slopes and C14 analyses gave ages between 20 000 and 30 000 years BP in areas close to the Sulmona Plain (e.g. Giraudi [1996]). The fault branch affecting the lower portion of the slope is responsible for the displacement of an alluvial fan succession whose upper portion has been related to the Late Pleistocene-Holocene by Vittori et al. [1995]. The correlation between early Pleistocene deposits in the footwall and in the hangingwall of the fault permitted Galadini and Galli [in press] to assess a long-term minimum vertical slip rate of 0.5–0.66 mm/yr. 4.2. Archaeoseismological evidence in the Sulmona Plain A memorial stone, presently located at the church of San Clemente a Casauria [site 1 in Fig. 12(a)], and originally found in the church area (Ludovico [1977]) testifies to the restoration of a weigh-house damaged by an earthquake (Fig. 14). This is the only source dealing with the event which, based on the age of the memorial stone, can be dated at the 2nd century A.D. (Boschi et al. [1995]). The archaeological excavations made in the villages of the Sulmona Plain [Fig. 12(a)] indicate a widespread crisis around the middle of the 2nd century AD with building collapses (occurred in the same period) extended over the entire area (Tuteri [1996]). At Sulmona [Fig. 12(a)] there are clear traces of rebuilding in this period. The remains of a domus excavated below the palace of SS. Annunziata are particularly interesting. The frescoes which decorated the walls of the domus were preserved by the collapse of entire portions of the walls and their rapid burial (Tuteri [1996]).

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Fig. 12. (a) Location map of the Sulmona Plain and traces of the main active faults affecting the area; sites 1 and 2 are the San Clemente a Casauria church and the Ercole Curino temple respectively; (b) intensity datapoints of the 1349 (I ≥ 8 MCS) and 1456 (I ≥ 7/8 MCS) earthquakes as taken from Boschi et al. [1997]; (c) intensity datapoints of the 1706 earthquake (I ≥ 8 MCS), from Boschi et al. [1997]; (d) intensity datapoints of the 1915 (I ≥ 7/8 MCS, from Galadini et al. [1995]) and 1933 (I ≥ 8 MCS, from Monachesi and Stucchi [1997]).


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Fig. 13. (a) View of the Mt. Morrone fault from Sulmona; (b) the main fault plane placing the cataclastic carbonate bedrock in contact with Late Pleistocene slope deposits.

Fig. 14. Epigraph of San Clemente a Casauria [site 1 in Fig. 12(a)] related to the restoration of a weigh-house damaged by an earthquake occurred around the middle of the 2nd century AD. Part of the word “terraemotus” (earthquake) is preserved at the third line, on the left side of the epigraph.

Subsequently, the building was completely stripped of the materials which could be reused for new buildings. Restorations were carried out extensively, as in the case of the via Mazara site, where even the floor was replaced by a new mosaic. New buildings subsequent to the event have been uncovered in the San Gaetano church (Tuteri [1996]). At all the sites there are traces of collapses and destruction horizons related to the same period. Clear traces of collapses have also been found at the Hercules Curinus temple [site 2 in Fig. 12(a)], located on the SW slope of Mt. Morrone and at the minor settlements located at the base of this slope (R. Tuteri, pers. comm.). Near Cansano the collapse of a temple has been dated around the middle of the 2nd century AD on the basis of the age of the findings buried by the collapsed walls (R. Tuteri, pers. comm.). At Raiano the excavation of a building of the villa rustica type at the Santa Petronilla site indicated the occurrence of a destructive event which affected the building around the middle of the 2nd century (R. Tuteri, pers. comm.).


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At Corfinio chronological constraints are less precise and it is possible to date the traumatic event between the half of the 1st century AD and the 3rd century AD (L. Brunetti, pers. comm.). However, also in this case the traces of collapses are widespread. In a 1st century AD domus the sudden collapse of a false ceiling has been observed. Archaeological excavations have uncovered an entire portion of it measuring 25 m × 2 m. The ante quem date for the event is given by the excavation of a grave in the ruins of the domus at the beginning of the 4th century AD. In a taberna two bronze coins of Antoninus Pius (138–161 AD) have been found in the ruins level, dating the destructive event after 138 AD. Fractures affect the building floors displacing different portions, at least in one case. Strong evidence of restorations has been observed in the thermae, whose operation continued until the 3rd century AD (Brunetti, pres. comm.). This date may represent the closer ante quem date for the catastrophic event. In such a case, synchronous evidence of a destruction affects different places inside one of the largest intermontane basins of central Italy. Considering the political stability of the investigated period (without wars inside this part of the Roman Empire), the ubiquitous evidence of building collapse is the probable effect of the seismic event testified by the above-mentioned memorial stone. Building collapse extended over the entire Sulmona basin and, above all, the complete destruction observed at some of the mentioned archaeological sites indicates the occurrence of a large magnitude event. 4.3. Seismicity of the Sulmona Plain The villages of the Sulmona Plain were significantly damaged by five earthquakes reported in the Italian seismic catalogues, namely the 1349, 1456, 1706, 1915 and 1933 events (Fig. 12) characterised by Ms = 5.9, 6.2, 6.4, 7.0, 5.5 respectively, according to Camassi and Stucchi [1997]. The archaeologically-inferred earthquake which affected this area around the middle of the 2nd century AD could be related to the activation of one of the faults responsible for the abovementioned events. However, in the case of the 1915 event (Fig. 12), as reported in a previous section, the fault responsible for this earthquake (Fucino fault) was probably also responsible for the earthquake occurred shortly before 508 AD, and recent paleoseismological studies allow to exclude the occurrence of a previous event in the 2nd century AD (Galadini et al. [1997b]). According to the most recent study (Boschi et al. [1995]), the 1933 earthquake was responsible for damage related to I = 8 (MCS) at Sulmona, but its effects at Cansano, Raiano, (I = 7 MCS, according to Boschi et al. [1995]) and Corfinio (I = 6/7 MCS; Boschi et al. [1995]) are quite modest (Fig. 12). Hence, the event responsible for the archaeologically-inferred strong damage is not likely to be compared with that occurred in 1933. The 1706 earthquake was responsible for the most significant historical damage in the Sulmona Plain (Fig. 12), in particular, for I = 10 MCS at Corfinio, I = 9/10 at Sulmona and Raiano and I = 8 at Cansano (Boschi et al. [1995]).


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Considering the damage distribution (high intensity values affect the areas to the east and south of the Sulmona Plain), the 1706 earthquake may have originated either by the activation of the NNE–SSW trending Maiella fault (OrtonaRoccamonfina line of Patacca et al. [1990]) or by the activation of the NW–SE trending Mt. Pizzalto fault (Fig. 12). However, the damage related to this earthquake in the Sulmona Plain appears to be consistent with the archaeologically-inferred damage related to the 2nd century AD event. The 1456 and 1349 earthquakes are among the largest events which affected the central-southern Apennines (Fig. 12), actually represented by seismic sequences (Boschi et al. [1995]; Monachesi and Stucchi [1997]). The 1456 earthquake affected large part of the central and the southern Apennines with high damage, though the most severely struck area is located in the southern Apennines (Fig. 12). The Sulmona basin can be considered as the northernmost area showing significant damage: Sulmona is reported with I = 8 MCS both in Boschi et al. [1995] and Monachesi and Stucchi [1997], while Vittorito (close to Raiano) is reported with I = 8/9 by Boschi et al. [1995] and I = 8 by Monachesi and Stucchi [1997]. Taking into account the damage distribution, Meletti et al. [1988] hypothesised that the same structure activated both in 1456 and in 1706. Knowledge on the 1349 events is poorer (Fig. 12). We only have intensity data for the study area related to Sulmona (I = 8/9; Boschi et al. [1995]; Monachesi and Stucchi [1997]), Tocco da Casauria (I = 9, according to Boschi et al. [1995]; I = 8/9, according to Monachesi and Stucchi [1997]), Pacentro (I = 7/8, Boschi et al. [1995]). As shown in Sec. 4.1, the Sulmona Plain is bounded to the east by an active fault, NW–SE trending and more than 20 km long, i.e. the Mt. Morrone Fault [Fig. 12(a)]. Its activation may probably result in earthquakes with M ≥ 6.5 and related catastrophic damage in the Sulmona area. However, available data on the long-term seismicity of this Apennine sector permit to exclude the occurrence of significant earthquakes (since 1000 AD) which may be related to this fault (Fig. 12). Some aspects related to the “silent” behaviour of the Mt. Morrone Fault will be discussed in the next section. 4.4. Implications In the case of the Sulmona Plain the available archaeological data (memorial stone, plus building collapse at five different sites) point to the occurrence of a large earthquake around the middle of the 2nd century AD. However, it is difficult to identify which event reported in the catalogues (1349, 1456, 1706) may be a recent “copy” of the archaeologically-inferred one. Alternatively, the 2nd century AD event may be related to the activation of the major NW–SE “silent” fault closely affecting the investigated area [Mt. Morrone Fault, Fig. 12(a)]. Paleoseismological data gathered on other active faults of the central Apennines, such as the Fucino or the Ovindoli-Pezza Faults indicate recurrence intervals for


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large magnitude earthquakes longer than 1400 years (e.g. Pantosti et al. [1996]; Galadini et al. [1997b]) with slip rates lower than 1 mm/yr. The Mt. Morrone fault has a minimum slip rate (0.5-0.66 mm/yr) which is consistent with that of the other central Apennine faults. The geometry of the fault and the expression of the recent activity (displacement of recent deposits and fault scarps affecting both the bedrock and the Late Pleistocene unconsolidated sediments; Vittori et al. [1995]) are the same as the other major Apennine active faults and suggest the repetition of surface faulting events (hence large magnitude earthquakes). Moreover, the available slip rate is typical of long recurrence intervals for surface faulting related to large magnitude events. The lack of large earthquakes since 1000 AD clearly related to the Mt. Morrone fault seems to confirm recurrence intervals for destructive events (related to this fault) larger than 1000 years. Therefore a strong earthquake of the 2nd century AD, if related to the Mt. Morrone fault, may represent the last episode of fault activation, occurred about 1800 years ago. Further archaeological research is currently being performed in the Sulmona Plain and adjacent areas. More data will probably permit to define a more complete framework of damage distribution related to this earthquake and possibly to make more precise hypotheses about the seismogenic fault.

5. The Trento Area 5.1. Active tectonics in the area between Trento and Verona Available data on this topic have already been reported in the sections dedicated to the Egna site. For the purpose of this section, however, further information about the faults of the Adige region may be useful to address the seismotectonic problems related to the 1117 earthquake (reported with Ms = 6.4 in Camassi and Stucchi [1997] and Me = 6.5 in Boschi et al. [1997]; epicentre location close to Verona in both catalogues). In addition to the already mentioned faults of the Giudicarie system (Sec. 3.4), evidence of recent tectonics affects the Mt. Baldo thrust and the reverse fault bordering the Lessini Mts. to the south, while no conclusive data are available for the NW–SE fault system (Schio–Vicenza system) affecting the Lessini Mts. and the Mt. Pasubio area (Fig. 7). As for the latter, minor seismicity (M = 4 − 5) is probably related to the Schio–Vicenza system and only some geomorphological works are available for the Lessini Mts. sector which hypothesise recent fault activity (Sauro [1978]). Significant seismicity may be related to the Mt. Baldo thrust, and earthquakes with M ≤ 5.5 have been recorded. According to Castaldini et al. [1988] the area of Mt. Baldo has been affected by significant uplift since the Middle Pleistocene. The top of the mountain is affected by a bedrock (carbonate) fault scarp, bordering an about 6 km long narrow valley (Fig. 15). The fault scarp, related to a typical normal


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Fig. 15. Bedrock fault scarp at the top of Mt. Baldo. The scarp has been interpreted as the result of recent normal faulting (gravity driven) at the top of an active compressive structure (Forcella and Sauro [1988]).

fault whose activity is conditioned by gravitational factors, has been reported in several works as an evidence of recent tectonics (e.g. Forcella and Sauro [1988]). Taking into account the seismic activity of this area, normal faulting at the top of this mountain is interpreted as a surficial response to the movements of the Mt. Baldo thrust (Forcella and Sauro [1988]). Regarding the reverse fault bordering the Lessini Mts. to the south, this is part of the long system of south-verging active reverse faults which affect the Alpine sector between the Adige river and the Friuli region (e.g. Castaldini and Panizza [1991]). Although detailed studies on active tectonics are lacking, evidence of recent activity is inferred from the uplift of a large paleo-landsurface in the Lessini Mts. (Castiglioni et al. [1988]), the anomalous trend of the Adige river which maintains its drainage very close to the Lessini fault scarp also in the Verona Plain (Castaldini et al. [1988]), the significant subsidence in this plain testified by the presence of Middle Pleistocene (later part) deposits at 78 m below the sea level (Castaldini et al. [1988]), faulting and fracturing of Quaternary deposits (Castaldini et al. [1988]). 5.2. Archaeological excavations at the San Lorenzo church (Trento) The San Lorenzo church at Trento (see Fig. 7 for location) was built in the second half of the 12th century AD (Gorfer, [1995] and references therein). During archaeological excavations in the area adjacent to the church, the remains of a previous building were discovered (Giovannini, [1997]; De Battaglia, [1997]; Fig. 16). Archaeologists uncovered the walls of the left nave and related apse and a portion


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Fig. 16. Archaeological excavations at the church of San Lorenzo (Trento, see Fig. 7 for location): (a) view of the left apse and related damage visible on the remnants of the wall; (b), (c) wall of the left nave.

of the central apse [Fig. 16(a)] of an ancient church. Remnants of the walls were 2–2.5 m high, 1 m thick and showed open vertical and horizontal fractures affecting the apse and tilting of the walls. In some cases, the walls appeared to be displaced along the fractures. A subhorizontal fracture affected a frescoed wall of the left nave [Figs. 16(b) and 16(c)]. In this case the upper portion of the wall had slid towards the inner part of the church. Vertical fractures also affected a Roman wall on which part of the left apse was built. The inner part of the nave was filled by the ruins of the church. Some boreholes have been made in this area, showing that the building is founded on a succession of sands and gravels and therefore it is unlikely that settlements affected the structure (Fig. 17). Moreover, the described subhorizontal fracture and the related displacement affecting the 1 m thick wall are consistent with an earthquake-induced horizontal acceleration. Therefore, on the basis of the above reported evidence, we suggest a seismic event as the most probable cause for the destruction. After the destructive event, the area adjacent to the destroyed church was progressively flattened with reworked deposits. During this phase, some graves were excavated in these deposits and radiocarbon dating of a human skeleton gave an


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Fig. 17.

Boreholes (and related location) in the area of the San Lorenzo church at Trento.


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age (subsequent to the destructive event) of 1170–1250 AD (cal. age). A date closer to the destructive event has been inferred from radiocarbon dating (995–1160 AD, cal. age) of a wood fragment taken from the helve of a hammer found inside the ruins of the church. The two other major churches in Trento (San Vigilio and Santa Maria Maggiore) were completely rebuilt in the 12th century. The reasons should be archaeologically investigated in the light of the evidence of the San Lorenzo church destruction. 5.3. Archaeological excavations at the San Martino church - Pranzo The medieval San Martino church is located at an archaeological site close to the Pranzo village, north of Lake Garda (Fig. 7). Archaeological excavations have uncovered the remains of an early church, whose construction has to be related to the High Middle Age (G. Ciurletti, pers. comm.; Fig. 18). Remains consist of 1.20 m high, about 0.5 m thick walls affected by open fractures [Figs. 18(a) and 18(b)], particularly evident in the apse. Ruins of the early church fill the inner side of the building and form the basement of a new church [Fig. 18(c)] which is probably related to the 12th century (G. Bernardi, pers. comm.) and whose walls seal the underlying fractures [Fig. 18(b)]. The apse

Fig. 18. Archaeological excavations at the church of San Martino (Pranzo, see Fig. 7 for location): (a), (b) fractures affecting the apse of the High Middle Age church; (c) ruins of the High Middle Age church, filling the area delimited by the remants of the old church and representing the basement of the church probably built in the 12th century AD; (d) concentric apses of the two churches.


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of the new church was built perfectly concentric and external to the earlier and fractured one [Fig. 18(d)]. The history of the church can be summarised as follows: (1) building of a High Middle Age church; (2) destructive event; (3) building of a new church probably in the 12th century. Geomorphological investigations made at the archaeological site and on aerial photographs permit to exclude landsliding among the causes of the destruction. Moreover the church was entirely built on the carbonate bedrock and this permits to exclude differential settlements. Therefore, also in this case, the most probable cause of destruction is seismic shaking and the available chronological constraints show that the age of this event may be comparable with that of the event detected at Trento. 5.4. The 1117 earthquake and the implications of the archaeoseismological research in the Trento area The 1117 earthquake is among the largest events which affected northern Italy (Ms = 6.4 in Camassi and Stucchi [1997]; Me = 6.5 in Boschi et al. [1997]) and according to Boschi et al. [1995] it resulted from two distinct shocks, the first having occurred in the night between January 2nd and 3rd (probably in southern Germany), the second in the early afternoon of January 3rd (in northern Italy). However, synchronous historical sources about this earthquake report few and generic descriptions of the damage. From these descriptions some damage may be inferred for Verona, Ronco all’Adige, Cremona and Parma (Fig. 19). In addition, there are 18 epigraphes (most of which located in the Verona area) 17 of which testify to restoration, building or rededication of churches in the years after the earthquake, while two epigraphes directly mention the earthquake (ENEL[1986]; Fig. 19). Historical data are lacking for the area north of Verona, probably due to the general lack of historical sources during the 12th century; yet information about probable damage in the Adige Valley has been reported by bishop Otto von Freising (Appendix A), who travelled throughout the region for four times some years after the earthquake (ENEL, [1986]). A specific study was carried out by ENEL [1986] on the architectural history of the Romanic churches in a large sector of northern Italy to identify evidence of possible crises related to the earthquake. On the basis of this study, ENEL [1986] identify 33 buildings for which damage due to the 1117 earthquake may be hypothesised. This method can define a sort of trend in the restoration/building activity which may be useful in the identification of possible high damage areas. Available data were reported on a map by Magri and Molin [1986] and have been used for drawing the map of Fig. 19. On this basis the epicentre of the earthquake is located in the Verona area (Boschi et al. [1995]), and the intensity in this area is considered not larger than 9 MCS by Magri and Molin [1986]. The knowledge on the architectural history


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Fig. 19. State of the art about the knowledge on the 1117 earthquake. The original database has been taken from ENEL [1986] and Magri and Molin [1986]. New points related to Romanic buildings have been inferred from Zanolini [1904], Agostini [1977], Ciurletti [1978], Chierici [1978], Rasmo [1981], Gorfer [1983] and [1995], Museo di Chiusa [1983], Stocchi [1984], Fogliardi [1987] and [1989], Bierbrauer and Nothdurfter [1988], Castagnetti and Varanini [1989], Comune di Drena [1990], Kersting [1991], Lorenzi [1991], Suitner [1991], Cavada [1991], [1992], [1996a] and [1996b], Mazzoleni [1993], Dal Ri and Rizzi [1993] and [1994], Alberti et al. [1995] and [1997], Rogger [1996], Trentini [1996], Ciurletti and Rizzi [1996], Dal Ri [1997].

of ancient churches and monuments of the region north of Verona has strongly improved since the second half of the 1980s. A large amount of bibliography has been recently produced on this topic and has permitted to increase the number of points related to the presence of Romanic buildings and to their restoration in the 12th century, after 1117 (Fig. 19). From a general point of view, the map of Fig. 19 shows that data distribution is a crucial point. For example, data on the Romanic buildings are fewer in the Trento and Padova areas than in the Verona one. Moreover, available data do not permit to exclude the reconstruction/restoration during the 12th century for a number of Romanic buildings whose location has been reported as open circles. Therefore, many open circles on the map are related to the location of Romanic buildings for which no data are available about the


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reconstruction/restoration. The map also shows, however, that the destruction of the old San Lorenzo church at Trento and of the San Martino church at Pranzo (which are chronologically constrained at the 12th century) may be consistent with a damage pattern related to the 1117 earthquake and with information from the historical source (Appendix A) and therefore a significant level of damage may have affected the Trento area. The definition of a more reliable damage distribution has profound implications with regards to the identification of the fault responsible for the 1117 earthquake. In fact, considering the Verona area as the epicentral area, the active structure most likely responsible for the 1117 event may be the reverse faults of the Lessini Mts. area (Fig. 7). On the contrary, a significant level of damage in the Trento area may indicate the activation of other structures (i.e. the Giudicarie System, such as the Mt. Baldo fault, the faults of the Garda area or of Mt. Pasubio; Fig. 7) as responsible for the 1117 event. Future archaeological research will cast light on this fundamental topic.

6. Conclusions Four Italian case studies show the use of archaeoseismology and paleoseismological techniques on displaced archaeological remains to improve the knowledge on the long-term seismicity. The use of paleoseismological techniques has been illustrated in the first two cases described. Trench excavation has permitted: (1) to reconstruct the geometric and kinematic characteristics of the shear planes affecting the displaced remains and, along with geomorphological analysis, (2) to collect data necessary for discriminating the cause of the displacements. Archaeological chronology and radiocarbon dating permitted to relate the displacement events to short time intervals. In the case analysed in the Fucino Plain (central Apennine), the displacement is unequivocally related to fault activity, while this origin is likely in the case of the Egna site (Adige Valley, northern Italy). In the two other cases, evidence of damage extended over a large area and related housing crisis or damage to single buildings are described. The damage of a number of buildings around the middle of the 2nd century AD in the Sulmona Plain (central Apennine) confirms that a strong earthquake (already known through epigraphic indication) affected the area. Evidence of earthquake-induced damage to single buildings in the Trento area (northern Italy) suggests that archaeoseismological research may bring significant data for the characterisation of the 1117 earthquake. All the described cases improve the knowledge of the long-term seismicity to a different extent: (1) The earthquake which damaged Rome shortly before 508 AD is likely to have occurred in the Fucino Plain, due to the activation of the same seismogenic structure which activated in 1915; if this is true, one can calculate the almost


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precise time interval between two subsequent activations of the same seismogenic fault (about 1407 years); (2) At Egna there is likely evidence of an earthquake responsible for surface faulting, around the middle of the 3rd century AD; obtained data indicate the possible occurrence of surface faulting in an area whose historical seismicity appears to be characterised by low-magnitude events; (3) The traces of earthquake-induced damage related to the middle of the 2nd century AD in the Sulmona Plain may be related to (a) a “twin” of one of the earthquakes reported in the available seismic catalogues and due to the activation of seismogenic structures affecting areas adjacent to the investigated one or to (b) the activation of the seismogenic fault which closely affects the Sulmona area; in the latter case the elapsed time since the last activation is probably about 1800 years; (4) Evidence of earthquake-induced damage to single buildings in the Trento area along with the only available historical source (Appendix A), suggests the possibility of extended damage related to the 1117 earthquake, whose epicentral area is presently located close to Verona; on this basis it is possible to hypothesise that the 1117 earthquake originated by the activation of one structure among those related to the Giudicarie system, the Mt. Pasubio domain or the flexural system bordering the Alpine chain towards the south. Gained experience shows that due to the abundance of archaeological settlements and seismological information spread over a long time span, Italy represents a valuable test area for archaeoseismological research. The cases reported in the present paper show that if historical research is hindered by the lack of primary sources, archaeoseismology (when applied together with paleoseismology, geomorphological and geotechnical analyses, etc.) represents a valuable tool for improving the knowledge on the long-term seismicity (related to moderate-large magnitude events). Acknowledgements The work has been partly supported by the EC DG XII (project ENV4-CT97-0578). We are grateful to all the archaeologists and geoarchaeologists who discussed with us the topics of this paper, gave us chronological indications about the history of the investigated sites and the available literature: M. Bersani, E. Cavada, G. Ciurletti, N. Pisu, S. Zamboni (Ufficio Beni Archeologici, Provincia Autonoma di Trento), L. Dal Ri (Soprintendenza Provinciale ai Beni Culturali, Bolzano), M. Bassetti (CORA, Trento), G. Bernardi (SAP, Mantova), L. Brunetti, V. D’Ercole, R. Tuteri (Soprintendenza Archeologica dell’Abruzzo, Chieti), R. Cairoli, G. Mieli (Archeores, Avezzano), R. Rea (Soprintendenza Archeologica di Roma). Aspects related to engineering problems have been discussed with G. Di Pasquale and G. Orsini (Servizio Sismico Nazionale, Roma). Discussions with D. Molin (Servizio Sismico


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Nazionale, Roma) about the 1117 earthquake were fundamental to better understand the problems related to this event. C. Giraudi (ENEA, Roma) participated to the fieldwork in the Fucino Plain and the survey of some trenches at the Egna site; P. Messina participated in the fieldwork made at sites 3 and 4 in the Fucino Plain. We are grateful to L. Veronese (Servizio Geologico, Provincia Autonoma di Trento) for the useful discussions, the release of instrumental data concerning regional seismicity and borehole data for the Trento area. Special thanks to M. Sperling (Ufficio Geologia Prove Materiali, Provincia Autonoma di Bolzano) for his continuous logistical support during the investigations at the Egna site, to L. Forgione (Accademia Nazionale dei Lincei, Roma) for helping us with the correct interpretation of the Otto von Freising’s quotation (App. A) and to C. Foti who translated it from Latin into English.

Appendix A “Ottonis Episcopi Frisingensis Chronica sive Historia De Duabus Civitatibus”, ed. Adolfus Hofmeister, in “Scriptores Rerum Germanicarum, in usum scholarum” ex “Monumentis Germaniae Historicis”, Hannoverae et Lipsiae, 1912, p. 330. “Circa idem tempus terrae motus horribilis oppida, templa, villas montesque plurimos, sicut usque hodie in valle Tridentina apparet, subvertit”. “At about the same time a horrible earthquake overturned towns, churches, houses and many mountains, as it is still visible today in the Tridentina Valley”. Note that the Tridentina Valley is the portion of the Adige Valley between Salorno (about 20 km North of Trento) and Verona.

References Agostini, B. [1977] “Appunti per la storia dell’antica pieve di Lomaso,” Trento, 230 pp. Alberti, A., Bombonato, G., Dal Ri, L., Hauser, L. and Rizzi, G. [1995] “Tutela dei Beni Culturali in Alto Adige, 1989/90. Beni Archeologici,” Bolzano, 313 pp. Alberti, A., Bombonato, G., Dal Ri, L., Demetz, S., Nothdurfter, H. and Rizzi, G. [1997] “Tutela dei beni culturali in Alto Adige, 1991/95. Beni archeologici,” Wien, Bolzano, 297 pp. Baroni, C. [1985] “Note sulla paleogeografia olocenica della costa occidentale del lago di Garda,” Geogr. Fis. Dinam. Quat. 8, 49–61. Bierbrauer, V. and Nothdurfter, H. [1988] “Die Ausgrabungen im sp¨ atantik– fr¨ uhmittelalterlichen Bischofssitz Sabiona-S¨ aben,” Der Schlern 62, 243–300. Boschi, E., Ferrari, G., Gasperini, P., Guidoboni, E., Smriglio, G. and Valensise, G. [1995] “Catalogo dei forti terremoti in Italia dal 461 a.C. al 1980,” Istituto Nazionale di Geofisica, SGA storia geofisica ambiente, Bologna, 973 pp. Boschi, E., Guidoboni, E., Ferrari, G., Valensise, G. and Gasperini, P. [1997] “Catalogo dei forti terremoti in Italia dal 461 a.C. al 1990, 2,” Istituto Nazionale di Geofisica, SGA storia geofisica ambiente, Bologna, 644 pp. Branca, M. E., Calderoni, G. and Petrone, V. [1989] “Geochemical and palaeoenvironmental significance of dating reversal in radiocarbon chronostratigraphy of lacustrine


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65

sediments: A case study from Castiglione valley (Latium, Italy),” Abstract 28th Int. Geol. Congr., July 9–19 1989, Washington DC. (USA), 3, 461. Brisse, A. and De Rotrou, L. [1883] “Prosciugamento del Lago Fucino fatto eseguire da sua eccellenza il Principe Alessandro Torlonia. Descrizione storica e tecnica,” Reprint, ed. S. D’Amato e U. M. Palanza, Avezzano, 1983 e 1985, 2 Vols., 322 e, 335 pp. Camassi, R. and Stucchi, M. [1997] “NT4.1, a parametric catalogue of damaging earthquakes in the Italian area (release NT4.1.1),” GNDT, Milano, 66 + XXVII pp. (Internet, http://emidius.itim.mi.cnr.it/NT/home.html). Carton, A. and Castaldini, D. [1987] “Nuovi indizi di neotettonica tra il lago di Garda e Verona,” ENEL (ed.), Contributi di preminente interesse scientifico agli studi di localizzazione di impianti nucleari in Piemonte e Lombardia (unpublished manuscript), 41–69. Castagnetti, A. and Varanini, G. M. [1989] “La cattedrale urbana,” in: Il Veneto nel medioevo. Dalla ‘Venetia’ alla Marca Veronese. Verona, 205–309. Castaldini, D. and Panizza, M. [1991] “Inventario delle faglie attive tra i fiumi Po e Piave e il Lago di Como (Italia settentrionale),” Il Quaternario 4, 333–410. Castaldini, D., Carton, A. and Panizza, M. [1988] “Description of the stops. IGU joint meeting on geomorphological hazards,” Guidebook for the excursions in the Modena and Verona areas, 118–128. Castellaccio, E. and Zorzin, R. [1996] “S. Faustino di Torri del Benaco (Verona): un esempio di evoluzione geomorfologica per frana di un tratto della riviera gardesana,” Il Quaternario, 9, 249–254. Castiglioni, G. B., Meneghel, M. and Sauro, U. [1988] “Elementi per una ricostruzione dell’evoluzione morfotettonica delle Prealpi Venete,” Suppl. Geogr. Fis. Dinam. Quat. 1, 31–43. Cavada, E. [1991] “La chiesa di S. Giuliana a Vigo di Fassa: Una stratigrafia archeologica per la storia del monumento,” in: Per Padre Frumenzio Ghetta. Scritti di storia e cultura ladina, trentina, tirolese e nota bio-bibliografica in occasione del settantesimo compleanno. Comune di Trento, Istitut Cultural Ladin, Vich-Vigo di Fassa, pp. 151–188. Cavada, E. [1992] “Elementi romani e germani nel territorio alpino tra Adige e Sarca: Aspetti e continuit` a dell’ insediamento,” in: Il territorio tra tardoantico e altomedioevo, metodi di indagine e risultati, Biblioteca di Archeologia Medievale, pp. 100–131. Cavada, E. [1996a] “La chiesa ‘scomparsa’: Indagini archeologiche nella chiesa di S. Vigilio a Molveno,” E. Cavada (ed.): S. Vigilio a Molveno. Una chiesa ritrovata. Comune di Moveno, Trento, pp. 31–62. Cavada, E. [1996b] “Persistenze edilizie nell’area della cappella,” in G. Fogliardi (ed.): Le pitture murali della cappella di S. Martino nel castello di Stenico. Beni Artistici e Storici del Trentino, Quaderni, 4, 22–35. Cavallin, A., Orombelli, G. and Sauro, U. [1988a] “Studio neotettonico del settore centromeridionale del ‘fascio giudicariense’,” ENEL (ed.), Contributi di preminente interesse scientifico agli studi di localizzazione di impianti nucleari in Piemonte e Lombardia (unpublished manuscript), pp. 210–231. Cavallin, A., Forcella, F., Orombelli, G. and Sauro, U. [1988b] “Le ‘scarpate-pareti di faglia’ del settore centro-meridionale del ‘fascio giudicariense’,” ENEL (ed.), Contributi di preminente interesse scientifico agli studi di localizzazione di impianti nucleari in Piemonte e Lombardia (unpublished manuscript), pp. 24–37. Chierici, S. [1978] “Lombardia,” in: Italia Romanica, Milano, 389 pp. Christlein, R. [1979] “Die Alamannen. Arch¨ aologie eines lebendingen Volkes,” Stuttgart und Aalen, pp. 179.


66

00023


Ciurletti. G [1978] “La zona archeologica di S. Maria Maggiore-Trento,” ed. Restauri acquisizioni 1973/78. Provincia Autonoma di Trento, Assessorato Attivit` a Culturali, pp. 305–310. Ciurletti, G. and Rizzi, G. [1996] “Santo Stefano di Fornace,” Provincia Autonoma di Trento, Societ` a Ricerche Archeologiche S.n.C., Trento, 20 pp. Comune di Drena [1990] “Castel Drena: Storia di una collina. Cinque anni di ricerca archeologica e di restauro monumentale,” Mori (Trento), 15 pp. Dal Ri, L. [1997] “Testimonianze di edifici sacri di epoca carolingia e ottoniana nell’alta valle dell’Adige. Gli scavi di Castel Tirolo,” Hortus Artium Medievalium, 3, 81–100. Dal Ri, L. and Zangirolami, P. [1985] “Egna, via Bolzano (sondaggi 1979),” in: “Scavi nella conca di Bolzano e nella bassa Atesina, 1976–1985”, catalogo mostra, Bolzano, pp. 231–234. Dal Ri, L. and Rizzi, G. [1993] “Bronzolo-San Leonardo,” in: Tutela dei Beni Culturali in Alto Adige, 1987/88. Beni Archeologici, Bolzano, pp. 21–22. Dal Ri, L. and Rizzi, G. [1994] “Territorio altoatesino,” in: Citt` a, castelli, campagne nei territori di frontiera (secoli VI-VII). Proc. of the 5th workshop on “Tardoantico e atomedioevo in Italia centrosettentrionale,” Monte Barro–Galbiate (Lecco), June 9–10, 1994, pp. 87–97. De Battaglia, F. [1997] “Muri romani oltre l’Adige. Una chiesa pi` u antica vicino a San Lorenzo,” Alto Adige, Dec. 3, 1997, p. 23. ENEL [1986] “Studi ed indagini per l’accertamento della idoneit` a tecnica delle aree suscettibili di insediamento di impianti nucleari, Regione Lombardia, Area Viadana, indagini di sismicit` a storica, rapporto finale, il terremoto del 3 gennaio 1117,” ISMES unpublished report RAT- DGF-0012, 907 pp. Fogliardi, G. [1987] “I frammenti altomedievali inseriti nell’abside romanica di San Lorenzo a Tenno: significato primario e traslato,” Studi Trentini di Scienze Storiche 66, 5–39. Fogliardi, G. [1989] “Gli affreschi romanici trentini di San Lorenzo a Tenno e di San Biagio a Mori,” Arte Veneta, 43, 13–24. Forcella, F. and Sauro, U. [1988] “Evoluzione morfotettonica del settore meridionale della dorsale del Monte Baldo (Prealpi Venete),” Suppl. Geogr. Fis. Dinam. Quat. 1, 83–87. Galadini, F. and Galli, P. [in press] “Active tectonics in the central Apennines (Italy) — input data for seismic hazard assessment,” Natural Hazards. Galadini, F. and Galli, P. [1999] “Paleoseismology related to the displaced Roman archaeological remains at Egna (Adige valley, northern Italy),” Tectonophysics 308, 171–191. Galadini, F. and Galli, P. [1996] “Paleoseismology related to deformed archaeological remains in the Fucino Plain, implications for subrecent seismicity in central Italy,” Annali di Geofisica 39, 925–940. Galadini, F., Galli, P., Bassetti, M. and Di Stefano, S. [1997a] “The displaced Roman building of Egna (Adige valley), northern Italy,” Il Quaternario 10, 407–410. Galadini, F., Galli, P. and Giraudi, C. [1997b] “Paleosismologia della Piana del Fucino (Italia centrale),” Il Quaternario 10, 27–64. Galadini, F., Galli, P., Giraudi, C. and Molin, D. [1995] “Il terremoto del 1915 e la sismicit` a della Piana del Fucino (Italia centrale),” Boll. Soc. Geol. It. 114, 635–663. Giovannini, M. [1997] “Un’antica chiesa sotto S. Lorenzo,” l’Adige, Dec. 3, 1997, p. 17. Giraudi, C. [1988] “Evoluzione geologica della Piana del Fucino (Abruzzo) negli ultimi 30.000 anni,” Il Quaternario 1, 131–159. Giraudi, C. [1996] “L’impronta del Younger Dryas degli Heinrich Events nell’evoluzione climatica e ambientale dell’Italia centrale,” Il Quaternario 9, 533–540. Gorfer, A. [1983] “Le valli del Trentino. Trentino occidentale,” Calliano (Trento), 895 pp.


00023


67

Gorfer, A. [1995] “Trento citta’ del Concilio,” Trento, 474 pp. Kersting, T. [1991] “La chiesa e le prime tombe: Evidenze archeologiche,” in: San Procolo a Naturno. La storia attraverso gli scavi. Gli uomini dell’alto medioevo e del tempo della peste. Catalogue of the exhibition, Museo Archeologico Provinciale di Castel Tirolo, July 12–November 3, 1991, pp. 12–26. Lorenzi, D. [1991] “I castelli del Trentino e Alto Adige,” Milano, 159 pp. Ludovico, D. [1977] “Il luogo e il nome della basilica di San Clemente a Casauria,” L’Universo 57, 833–864. Magri, G. and Molin, D. [1986] “I terremoti del 3 gennaio 1117 e del 25 dicembre 1222,” ENEA report, RTI PAS-ISP-GEOL LO (86)2, Roma, 9 pp. Margottini, C., Ambraseys, N. N. and Screpanti, A. [1993] “La magnitudo dei terremoti italiani del XX secolo,” ENEA report, Direzione Relazioni Esterne, Roma, 57 pp. Mazzoleni, D. [1993] “Mosaici pavimentali paleocristiani in territorio trentino,” Archeoalp Archeologia delle Alpi 2, 159–173. Meletti, C., Patacca, E., Scandone, P. and Figliuolo, B. [1988] “Il terremoto del 1456 e la sua interpretazione nel quadro sismotettonico dell’Appennino meridionale,” ed. B. Figliuolo “Il terremoto del 1456,” Osservatorio Vesuviano, Istituto Italiano di Studi Filosofici, Storia e Scienze della Terra 1, 71–108. Mertens, J. [1969] “Alba Fucens,” Centre Belge de Recherches Archéologiques en Italie centrale et Méridionale. Bruxelles, 2 vols., 105 and 124 pp. Mertens, J. [1989] “Recenti scavi ad Alba Fucens,” Proc. of the congress “Il Fucino e le aree limitrofe nell’antichit´ a,” Avezzano (Italia), 10–11 November 1989, pp. 387–405. Molin, D., Castenetto, S., Di Loreto, E., Guidoboni, E., Liperi, L., Narcisi, B., Paciello, A., Riguzzi, F., Rossi, A., Tertulliani, A. and Traina, G. [1995] “Sismicit` a di Roma,” Mem. Descr. Carta Geol. d’Italia 50, 327–408. Molinari, M. C. [1994] “Discussione,” ed. Francovich R and Noyé G. “La Storia dell’alto Medioevo italiano (VI-X secolo) alla luce dell’archeologia,” Firenze, 540–541. Monachesi, G. and Stucchi, M. [1997] “DOM 4.1 an intensity database of damaging earthquakes in the Italian area,” Internet address, http://emidius.itim.mi.cnr.it/DOM/ home.html Museo di Chiusa [1983] “Gli scavi di Sabiona,” Catalogue of the exhibition, June–October 1983, 2 pp. Pantosti, D., D’Addezio, G. and Cinti, F. R. [1996] “Paleoseismicity of the Ovindoli-Pezza fault, central Apennines, Italy: A history including a large, previously unrecorded earthquake in the Middle Ages (860–1300 AD),” J. Geophys. Res. 101, 5937–5959. Patacca, E., Sartori, R. and Scandone, P. [1990] “Tyrrhenian basin and penninic arcs: kinematic relations since Late Tortonian times,” Mem. Soc. Geol. It. 45, 425–451. Prosser, G. [1998] “Strike-slip movements and thrusting along a transpressive fault zone: The North Giudicarie line (Insubric line, northern Italy),” Tectonics 17, 921–937. Rasmo, N. [1981] “San Benedetto a Malles,” Bolzano, 18 pp. Rea, R. [1993] “Il Colosseo e la valle da Teodorico ai Frangipane: Note di studio,” eds. Paroli, L. and Delogu, P., “La storia economica di Roma nell’alto Medioevo alla luce dei recenti scavi archeologici,” Firenze, pp. 71–88. Reece, R. [1984] “Coins,” eds. Hurst, H. R. and Roskams, S. P. “Excavations at Carthage: the British Mission,” Sheffield, 1, pp. 171–181. Rogger, I. [1996] “La basilica paleocristiana di S. Vigilio,” ed. Primerano, D.: Il museo Diocesano Tridentino, Trento, pp. 137–144. Sauro, U. [1978] “Forme strutturali e neotettoniche nei Monti Lessini,” Gruppo di Studio del Quaternario Padano 4, 31–60. Slejko, D., Carulli, G. B., Nicolich, R., Rebez, A., Zanferrari, A., Cavallin, A., Doglioni,


68

00023


C., Carraro, F., Castaldini, D., Iliceto, V., Semenza, E. and Zanolla, C. [1989] “Seismotectonics of the eastern Southern-Alps: a review,” Boll. di Geof. Teor. ed Appl. 31, 109–136. Stocchi, S. [1984] “L’Emilia-Romagna,” in: Italia Romanica, Milano, 483 pp. Suitner, G. [1991] “Le Venezie,” in: Italia Romanica, Milano, 436 pp. Trentini, C. [1996] “Da Pons Drusi a Bolzano. Iconografia e icnografia della citt` a,” Bolzano, 110 pp. Tuteri, R. [1996] “Il contesto urbano: Le porte malchiuse dell’antica Sulmo,” In: Mattiocco E and Papponetti G. (eds.), “Sulmona citt` a d’arte e poeti,” Pescara, 30–40. Vittori, E., Cavinato, G. P. and Miccadei, E. [1995] “Active faulting along the northeastern edge of the Sulmona basin, Central Apennines, Italy,” Ass. of Eng. Geologists, Spec. 6, 83–100. Zanferrari, A., Bollettinari, G., Carobene, L., Carton, A., Carulli, G. B., Castaldini, D., Cavallin, A., Panizza, M., Pellegrini, G. B., Pianetti, F. and Sauro, U. [1982] “Evoluzione neotettonica dell’Italia nord-orientale,” Mem. di Sc. Geologiche, 35, 355–376. Zanolini, P. [1904] “La chiesa di S. Michele di Riva. Cenni Storici,” Riva del Garda (Trento), 13 pp.