Academia.eduAcademia.edu

Figure 23 – uploaded by Paolo Galli

See full PDFdownloadDownload figure
Fig. 23. View looking ~south of a trench dug in the modern settlement of Cittanova close to the site pictured in Fig. 1. This excavation was very difficult, as it was carried out across the only remains of the fault scarp, between two houses (see Galli and Bosi, 2002). The footwall is composed of ~ LGM alluvial and colluvial deposits, and is faulted against Holocene colluvia.

Figure 23 View looking ~south of a trench dug in the modern settlement of Cittanova close to the site pictured in Fig. 1. This excavation was very difficult, as it was carried out across the only remains of the fault scarp, between two houses (see Galli and Bosi, 2002). The footwall is composed of ~ LGM alluvial and colluvial deposits, and is faulted against Holocene colluvia.

Related Figures (26)

Fig. 1. May 22, 1783, Calabria — Southern Italy. Sitting on his folding-stool, Pompeo Schiantarelli draws the strange chasm he is facing at the foothill of the Aspromonte massif. In the days before, he has seen burning towns razed to the ground, dead bodies, landslides and hundreds of newly formed lakes; but this capriccio of Nature, cutting through the road towards the Ionian coast of Calabria, is an absolutely new and intriguing fact for him. While he is wondering how many miles long his finding is, Michele Sarconi, the chief of the expedition, collects news on the earthquake effects in the nearby Casalnuovo village. Here, more than on the death of Princess Grimaldi under the ruins of her own palace, the survivors are holding forth on that infinite split which lowered the entire plain where they live. Actually, neither one nor the other of the scholars are aware that they are immortalizing the first surface faulting case ever portrayed in history (Cittanova fault, earthquake of February 5, 1783. Mw=6.9). Note the main free-face (A) along the fault scarp (C), and the blocks that have fallen down from the hanging wall (B). Considering the height of the man measuring a secondary splay across the road, the free-face in A is 1.2+0.1 m high. This is the place where Galli and Bosi (2002) excavated one of their paleoseismic trenches across this fault.
Fig. 1. May 22, 1783, Calabria — Southern Italy. Sitting on his folding-stool, Pompeo Schiantarelli draws the strange chasm he is facing at the foothill of the Aspromonte massif. In the days before, he has seen burning towns razed to the ground, dead bodies, landslides and hundreds of newly formed lakes; but this capriccio of Nature, cutting through the road towards the Ionian coast of Calabria, is an absolutely new and intriguing fact for him. While he is wondering how many miles long his finding is, Michele Sarconi, the chief of the expedition, collects news on the earthquake effects in the nearby Casalnuovo village. Here, more than on the death of Princess Grimaldi under the ruins of her own palace, the survivors are holding forth on that infinite split which lowered the entire plain where they live. Actually, neither one nor the other of the scholars are aware that they are immortalizing the first surface faulting case ever portrayed in history (Cittanova fault, earthquake of February 5, 1783. Mw=6.9). Note the main free-face (A) along the fault scarp (C), and the blocks that have fallen down from the hanging wall (B). Considering the height of the man measuring a secondary splay across the road, the free-face in A is 1.2+0.1 m high. This is the place where Galli and Bosi (2002) excavated one of their paleoseismic trenches across this fault.
Fig. 2. View looking NE of the fault rupture of the 1980 earthquake (Mw=6.9) at Piano di Pecore (Irpinia, southern Italy). Note the superficial break associated wit the warping of the field. In this site, Pantosti et al. (1993) excavated one of their trenches, finding evidence of several previous twin events (photo by courtesy of M Sorriso Valvo).
Fig. 2. View looking NE of the fault rupture of the 1980 earthquake (Mw=6.9) at Piano di Pecore (Irpinia, southern Italy). Note the superficial break associated wit the warping of the field. In this site, Pantosti et al. (1993) excavated one of their trenches, finding evidence of several previous twin events (photo by courtesy of M Sorriso Valvo).
Fig. 3. Main structural and kinematics features of the Italian orogen, within the relative motion of the Europe, Adria and Africa plates. The thin dashed arrows roughly indicate the slip-vectors of Adria vs Europe (see rotation pole, RP, according to Meletti et al., 2000) and Africa vs Europa. Black arrows indicate VLBI and SRL velocities (mm/yr; Ward, 1994). The bold continuous line is the compressive front of the Alpine—Apennine chain (northern and southern Apennine Arcs, NAA and SAA, respectively). Quaternary volcanoes and isobaths (in km) of the Ionian lithospheric slab (dashed lines in southern Tyrrhenian basin) are also shown. Gray circles are the M>5.5 earthquakes (only for Italy; CPTI04). Note that the seismicity occurs mainly along the central- southern Appenine chain, and partly in eastern Sicily and the eastern southern Alps. The “fragmented” line along the Apennine axis depicts the known outcropping seismogenetic faults; most of which have been investigated by means of paleoseismological studies that are partly described in this manuscript.
Fig. 3. Main structural and kinematics features of the Italian orogen, within the relative motion of the Europe, Adria and Africa plates. The thin dashed arrows roughly indicate the slip-vectors of Adria vs Europe (see rotation pole, RP, according to Meletti et al., 2000) and Africa vs Europa. Black arrows indicate VLBI and SRL velocities (mm/yr; Ward, 1994). The bold continuous line is the compressive front of the Alpine—Apennine chain (northern and southern Apennine Arcs, NAA and SAA, respectively). Quaternary volcanoes and isobaths (in km) of the Ionian lithospheric slab (dashed lines in southern Tyrrhenian basin) are also shown. Gray circles are the M>5.5 earthquakes (only for Italy; CPTI04). Note that the seismicity occurs mainly along the central- southern Appenine chain, and partly in eastern Sicily and the eastern southern Alps. The “fragmented” line along the Apennine axis depicts the known outcropping seismogenetic faults; most of which have been investigated by means of paleoseismological studies that are partly described in this manuscript.
Fig. 4. Shaded relief map of north-eastern Italy, showing the main Pleistocene thrust system (mainly buried; bold lines refer to S-verging Alpine structures) and major earthquakes (from CPTI, 2004). The two boxes indicate the possible locations of two different 1117 sources; modified from Galadini et al., 2005; Galli, 2006). EF, Egna fault (part of the NNE—SSW Giudicarie fault system); MBF, Mount Baldo fault (Giudicarie fault system) and OF, Orsara fault (Lessini Mounts fault system) are the only trenched faults in the Alps. The thrusts responsible for almost all of the destructive earthquakes of north-eastern Italy are mainly blind, and have not allowed, to date, any paleoseismological trenching. Conversely, the three trenched faults have been seismically silent in historical times.
Fig. 4. Shaded relief map of north-eastern Italy, showing the main Pleistocene thrust system (mainly buried; bold lines refer to S-verging Alpine structures) and major earthquakes (from CPTI, 2004). The two boxes indicate the possible locations of two different 1117 sources; modified from Galadini et al., 2005; Galli, 2006). EF, Egna fault (part of the NNE—SSW Giudicarie fault system); MBF, Mount Baldo fault (Giudicarie fault system) and OF, Orsara fault (Lessini Mounts fault system) are the only trenched faults in the Alps. The thrusts responsible for almost all of the destructive earthquakes of north-eastern Italy are mainly blind, and have not allowed, to date, any paleoseismological trenching. Conversely, the three trenched faults have been seismically silent in historical times.
Fig. 5. The image shows the impressive faulting of the walls of the Imperial Roman villa of Endidae (currently Egna-Neumarkt); panel A shows a detail of the faulted northern wall, where A is the stone-wall (lost in the footwall), B the foundation, and C the alluvial deposits that the villa was built on. Note both the vertical (0.7 m) and horizontal (0.2 m) shifting of the building wall. In panel B, the courtyard floor (D) unearthed by the archaeologists shows the fossilized free-face (E). This earthquake was dated around halfway through the 3rd century AD, whereas a previous event occurred in the middle of the 3rd millennium BC. Unfortunately, at present, this site has been mostly destroyed by a residential house that was built both on the Roman villa, and across the fault (photos by P.G.).
Fig. 5. The image shows the impressive faulting of the walls of the Imperial Roman villa of Endidae (currently Egna-Neumarkt); panel A shows a detail of the faulted northern wall, where A is the stone-wall (lost in the footwall), B the foundation, and C the alluvial deposits that the villa was built on. Note both the vertical (0.7 m) and horizontal (0.2 m) shifting of the building wall. In panel B, the courtyard floor (D) unearthed by the archaeologists shows the fossilized free-face (E). This earthquake was dated around halfway through the 3rd century AD, whereas a previous event occurred in the middle of the 3rd millennium BC. Unfortunately, at present, this site has been mostly destroyed by a residential house that was built both on the Roman villa, and across the fault (photos by P.G.).
Fig. 8. A, View looking NW of the superficial break caused by one the 1997 main shocks (October 14, Mw=5.6), cutting the road between the villages of Mevale and Renaro (arrows). Along the 5-km-long rupture, the offset ranged between 2—3 cm and 20 cm. Trench analysis carried out in the field below and above (panel B) this road (Pantosti et al., 1999) revealed the occurrence of a previous, stronger event, possibly related to the 1279 earthquake (Mw=6.3). B, southern wall of the Mevale trench, revealing the complex deformation affecting the historical colluvia and the ground surface (photos by P.G.). [1 T; 2 PE]. The SW slope of the arenaceous Mount Gorzano ridge (2458 m a.s.1.; part of the Laga chain) is bounded by a 30- km-long, NW-—SE-tending fault that is part of the EFS. This fault controls the Campotosto (south) and Amatrice (north) inter- montane basins (Bachetti et al., 1990), with late-Pleistocene activity suggested by fault scarps in both the bedrock and the middle Holocene alluvial terraces (Galadini and Galli, 2000). Because this evidence of activity is confined in the Campotosto [10 T; 2 PE]. This fault is located along the WFS and i: part of the 27-km-long Norcia fault system (Galadini anc Galli, 2000), which since early Pleistocene, has bound anc controlled the opening of the homonymous basin (Calamita e al., 1982). The entire system is segmented into four en: echelon main faults (Preci, Campi, Norcia, Mount Alvag.
Fig. 8. A, View looking NW of the superficial break caused by one the 1997 main shocks (October 14, Mw=5.6), cutting the road between the villages of Mevale and Renaro (arrows). Along the 5-km-long rupture, the offset ranged between 2—3 cm and 20 cm. Trench analysis carried out in the field below and above (panel B) this road (Pantosti et al., 1999) revealed the occurrence of a previous, stronger event, possibly related to the 1279 earthquake (Mw=6.3). B, southern wall of the Mevale trench, revealing the complex deformation affecting the historical colluvia and the ground surface (photos by P.G.). [1 T; 2 PE]. The SW slope of the arenaceous Mount Gorzano ridge (2458 m a.s.1.; part of the Laga chain) is bounded by a 30- km-long, NW-—SE-tending fault that is part of the EFS. This fault controls the Campotosto (south) and Amatrice (north) inter- montane basins (Bachetti et al., 1990), with late-Pleistocene activity suggested by fault scarps in both the bedrock and the middle Holocene alluvial terraces (Galadini and Galli, 2000). Because this evidence of activity is confined in the Campotosto [10 T; 2 PE]. This fault is located along the WFS and i: part of the 27-km-long Norcia fault system (Galadini anc Galli, 2000), which since early Pleistocene, has bound anc controlled the opening of the homonymous basin (Calamita e al., 1982). The entire system is segmented into four en: echelon main faults (Preci, Campi, Norcia, Mount Alvag.
Fig. 7. January 1915; view looking west of Avezzano and its medieval castl (right), completely razed to the ground by the Mw=7 earthquake (Fucino faul system; unpublished photo). Avezzano had >80% mortality, with ~ 11,00( casualties. This event was totally unexpected at the time, and just one hundrex years ago we would probably have considered the Fucino faults as “silent” Recent paleoseismological investigations have shown that the Fucino basin ha: been periodically struck by earthquakes like this.
Fig. 7. January 1915; view looking west of Avezzano and its medieval castl (right), completely razed to the ground by the Mw=7 earthquake (Fucino faul system; unpublished photo). Avezzano had >80% mortality, with ~ 11,00( casualties. This event was totally unexpected at the time, and just one hundrex years ago we would probably have considered the Fucino faults as “silent” Recent paleoseismological investigations have shown that the Fucino basin ha: been periodically struck by earthquakes like this.
Fig. 10. View looking south of a cellar excavated inside Late Pleistocene cemented gravels, across the Norcia fault (central Italy). During the 1979 Mw=5.9 earthquake, this fault ruptured, generating discontinuous superficial breaks, with centimeter offsets. The photo shows the normal faulting effects on walls, ceiling and floor (the famous Norcia ham is aged in cellars like this, with the special earthquake flavour; photo by P.G.).
Fig. 10. View looking south of a cellar excavated inside Late Pleistocene cemented gravels, across the Norcia fault (central Italy). During the 1979 Mw=5.9 earthquake, this fault ruptured, generating discontinuous superficial breaks, with centimeter offsets. The photo shows the normal faulting effects on walls, ceiling and floor (the famous Norcia ham is aged in cellars like this, with the special earthquake flavour; photo by P.G.).
Fig. 9. View looking north of the Mount Vettore slope, and of the Castelluccio intermontane basin. Note the prominent fault scarp affecting the upper part of the hillslope. The bulldozer indicates the site where Galadini and Galli (2003) dug four trenches across a secondary fault splay (photo by P.G.).
Fig. 9. View looking north of the Mount Vettore slope, and of the Castelluccio intermontane basin. Note the prominent fault scarp affecting the upper part of the hillslope. The bulldozer indicates the site where Galadini and Galli (2003) dug four trenches across a secondary fault splay (photo by P.G.).
Fig. 11. View looking north of one of the excavations across the urban sector of the Norcia fault (note the house behind; grid 1 m). The dark paleosol (A) interbedded in the alluvial fan gravel (B) has been dated ~ 25 kyr BP. Colluvia in the hanging wall are of late Holocene—18th century AD. Note the colluvial wedge (C) made up of the coarse gravels fallen down from B, which has been faulted by a later event (i.e., the 1703 earthquake). D is the fault zone (photo by P.G.; unpublished data).
Fig. 11. View looking north of one of the excavations across the urban sector of the Norcia fault (note the house behind; grid 1 m). The dark paleosol (A) interbedded in the alluvial fan gravel (B) has been dated ~ 25 kyr BP. Colluvia in the hanging wall are of late Holocene—18th century AD. Note the colluvial wedge (C) made up of the coarse gravels fallen down from B, which has been faulted by a later event (i.e., the 1703 earthquake). D is the fault zone (photo by P.G.; unpublished data).
Fig. 12. View looking north of the Valle Venacquaro fault (Gran Sasso fault system), running along the northern slopes of the Gran Sasso massif. The fault dips southwards, damming the natural drainage. The arrow indicates the site where Giraudi and Frezzotti (1995) dug a hand-made trench (photo by C. Giraudi). trenches that were excavated in the Campo Imperatore plain across secondary faults (Galli et al., 2002b; Galadini et al., 2003) showed evidence of: a more recent event that occurred after 3480-3400 BP; a penultimate event that occurred between 7155-7120 BP and 5545-5475 BP; and the oldest event that was during the Late Pleistocene. The data from the two sites are in agreement and support the hypothesis of the rupture of the 3.2./. [he Cerasitto-Campo Felice-Ovindoli-Pezza fault system [13 T; 3 PE]. This 27-km-long fault system is composed of four main strands, tending from NNW-SSE (Ovindoli strand),
Fig. 12. View looking north of the Valle Venacquaro fault (Gran Sasso fault system), running along the northern slopes of the Gran Sasso massif. The fault dips southwards, damming the natural drainage. The arrow indicates the site where Giraudi and Frezzotti (1995) dug a hand-made trench (photo by C. Giraudi). trenches that were excavated in the Campo Imperatore plain across secondary faults (Galli et al., 2002b; Galadini et al., 2003) showed evidence of: a more recent event that occurred after 3480-3400 BP; a penultimate event that occurred between 7155-7120 BP and 5545-5475 BP; and the oldest event that was during the Late Pleistocene. The data from the two sites are in agreement and support the hypothesis of the rupture of the 3.2./. [he Cerasitto-Campo Felice-Ovindoli-Pezza fault system [13 T; 3 PE]. This 27-km-long fault system is composed of four main strands, tending from NNW-SSE (Ovindoli strand),
Fig. 13. View of one of the trenches excavated by Pantosti et al. (1996) across the Piano di Pezza border fault. Paleoseismological analysis accounted for thr Holocene events, the last one occurred during the Middle Ages (photo by D.P.). Since the paleosol was buried by a fault scarp-related colluvial wedge, it is probable that the earthquake occurred at a time that was very close to the paleosol age. This earthquake does not match with any known historical earthquake of the region. The penultimate event was dated ~3900 BP, whereas the oldest probably occurred between 7000 and 5300 BP. On the other hand, Salvi et al. (2003) dug five trenches across the northernmost strand (the Colle Cerasitto fault), and found evidence for four surface faulting events in the past 20 kyr. The last three of these occurred after 7.2 BP, with the datings roughly fitting with those obtained at Piano di Pezza. In particular, the most recent event is dated between 3640 BP and 1700 AD, the penultimate between 7570 and 3375 BP, and the previous one shortly after 7000 BP. However, it is possible that the Ovindoli-Pezza and Campo Felice-Colle Cerasitto faults can rupture separately, thus originating earthquakes of lower magnitude (~ 6.3) than the one expected for the entire fault system rupture (/=6.7). The time recurrence for this fault has been evaluated as ~3 kyr. [15 I; 10 PE}. The Fucino Plain 1s the major intermontane basin of the central Apennines, and it is filled with more than 1 km of lacustrine and fluvial Plio-Quaternary deposits and surrounded by Meso-Cenozoic carbonate mountains (at an average of 2000 ma.s.1.). Since the Late Pliocene, the NW-SE tending faults that are located along the eastern border of the plain (Marsicana Hwy fault and San Benedetto dei Marsi-Gioia dei Marsi fault) have controlled the development of the basin, together with secondary splays, i.e., the Trasacco and the Luco dei Marsi faults. Together with the neighboring Velino fault, these faults form a 38-km-long system within the WFS. On 13 January, 1915, the plain was struck by one of the most catastrophic earthquakes ever to be recorded in all of the Mediterranean area, which caused more than 30,000 casualties (Molin et al., 1999) and surface faulting (Oddone, 1915; Serva et al., 1986; Galadini et al., 1993, 1995a,b, 1997a,b, 1999a,b; Michetti et al., 1996). The 1915 catastrophe surprised Italian seismologists at the time (i.e., Baratta, 1915), because the Fucino was considered as an aseismic area. Today, its long prehistory of seismicity is known due to the excavation ofa dozen trenches across the faults, bounding and crossing the former lake that was reclaimed by the Torlonia family at the end of the 1800’s. The first paleoseismic information derives from recognition of contemporary collapses in caves by Giraudi (1988): these collapse events were dated at 5.5—5.0 kyr BP, 3.5—3.0 kyr BP, and the late Roman-high Middle Age period. Later, two trenches were dug across the San Benedetto dei Marsi fault (Brunamonte et al., 1991; Michetti et al., 1996) that exposed the traces of two events of surface deformation, one occurred after 1375+75 BP, and the other between the 9th and 14th century AD. Thirteen new excavations and cores across the four main faults of the basin have provided a more complete history of the activity of this structure (Galadini et al., 1997a,b; Galadini and Galli, 1996, 1999a). These
Fig. 13. View of one of the trenches excavated by Pantosti et al. (1996) across the Piano di Pezza border fault. Paleoseismological analysis accounted for thr Holocene events, the last one occurred during the Middle Ages (photo by D.P.). Since the paleosol was buried by a fault scarp-related colluvial wedge, it is probable that the earthquake occurred at a time that was very close to the paleosol age. This earthquake does not match with any known historical earthquake of the region. The penultimate event was dated ~3900 BP, whereas the oldest probably occurred between 7000 and 5300 BP. On the other hand, Salvi et al. (2003) dug five trenches across the northernmost strand (the Colle Cerasitto fault), and found evidence for four surface faulting events in the past 20 kyr. The last three of these occurred after 7.2 BP, with the datings roughly fitting with those obtained at Piano di Pezza. In particular, the most recent event is dated between 3640 BP and 1700 AD, the penultimate between 7570 and 3375 BP, and the previous one shortly after 7000 BP. However, it is possible that the Ovindoli-Pezza and Campo Felice-Colle Cerasitto faults can rupture separately, thus originating earthquakes of lower magnitude (~ 6.3) than the one expected for the entire fault system rupture (/=6.7). The time recurrence for this fault has been evaluated as ~3 kyr. [15 I; 10 PE}. The Fucino Plain 1s the major intermontane basin of the central Apennines, and it is filled with more than 1 km of lacustrine and fluvial Plio-Quaternary deposits and surrounded by Meso-Cenozoic carbonate mountains (at an average of 2000 ma.s.1.). Since the Late Pliocene, the NW-SE tending faults that are located along the eastern border of the plain (Marsicana Hwy fault and San Benedetto dei Marsi-Gioia dei Marsi fault) have controlled the development of the basin, together with secondary splays, i.e., the Trasacco and the Luco dei Marsi faults. Together with the neighboring Velino fault, these faults form a 38-km-long system within the WFS. On 13 January, 1915, the plain was struck by one of the most catastrophic earthquakes ever to be recorded in all of the Mediterranean area, which caused more than 30,000 casualties (Molin et al., 1999) and surface faulting (Oddone, 1915; Serva et al., 1986; Galadini et al., 1993, 1995a,b, 1997a,b, 1999a,b; Michetti et al., 1996). The 1915 catastrophe surprised Italian seismologists at the time (i.e., Baratta, 1915), because the Fucino was considered as an aseismic area. Today, its long prehistory of seismicity is known due to the excavation ofa dozen trenches across the faults, bounding and crossing the former lake that was reclaimed by the Torlonia family at the end of the 1800’s. The first paleoseismic information derives from recognition of contemporary collapses in caves by Giraudi (1988): these collapse events were dated at 5.5—5.0 kyr BP, 3.5—3.0 kyr BP, and the late Roman-high Middle Age period. Later, two trenches were dug across the San Benedetto dei Marsi fault (Brunamonte et al., 1991; Michetti et al., 1996) that exposed the traces of two events of surface deformation, one occurred after 1375+75 BP, and the other between the 9th and 14th century AD. Thirteen new excavations and cores across the four main faults of the basin have provided a more complete history of the activity of this structure (Galadini et al., 1997a,b; Galadini and Galli, 1996, 1999a). These
Fig. 14. View of one of the thirteen trenches excavated by Galadini et al. (1997a,b) across the Fucino fault system (Trasacco fault). 1, gravel; 2—3 grey clay (2v, tephr: level); 4—5, laminated silt; 6, brown silt (Roman age before Ist cent. BC); 7—9, silt (post-1st BC age). Five Holocene events have been detected in this site, the last on being the Mw=7.0, 1915 earthquake (photo by P.G.).
Fig. 14. View of one of the thirteen trenches excavated by Galadini et al. (1997a,b) across the Fucino fault system (Trasacco fault). 1, gravel; 2—3 grey clay (2v, tephr: level); 4—5, laminated silt; 6, brown silt (Roman age before Ist cent. BC); 7—9, silt (post-1st BC age). Five Holocene events have been detected in this site, the last on being the Mw=7.0, 1915 earthquake (photo by P.G.).
Fig. 15. Top, view looking SW of the “graben” that opened along the Aremogna fault segment (eastern border of the Aremogna basin). D’ Addezio et al. (2001) openec two trenches across both the synthetic and antithetic faults of this feature. Bottom, view looking north of the trench excavated by Galli et al. (2006c) across the easter border fault; the dark paleosol (5) is offset by at least 11 m across the whole fault zone (i.e., the main fault affecting the Mesozoic carbonate on the right; photos by P.G.)
Fig. 15. Top, view looking SW of the “graben” that opened along the Aremogna fault segment (eastern border of the Aremogna basin). D’ Addezio et al. (2001) openec two trenches across both the synthetic and antithetic faults of this feature. Bottom, view looking north of the trench excavated by Galli et al. (2006c) across the easter border fault; the dark paleosol (5) is offset by at least 11 m across the whole fault zone (i.e., the main fault affecting the Mesozoic carbonate on the right; photos by P.G.)
Fig. 16. Shaded relief of southern Apennines with certain and trenched seismogenetic faults (modified from Galli and Galadini, 2003) and major earthquakes (modified from CPTI, 2004). AFI, Aquae Iuliae fault (Galli and Naso, in prep); NMFS, northern Matese Mounts faults; UF, Ufita fault; MFS, Mount Marzano fault system; CF, Caggiano fault. This image, with few scattered faults, reflects the poor knowledge concerning seismogenetic structures in this sector of the chain, which is, conversely, affected by strong and frequent earthquakes.
Fig. 16. Shaded relief of southern Apennines with certain and trenched seismogenetic faults (modified from Galli and Galadini, 2003) and major earthquakes (modified from CPTI, 2004). AFI, Aquae Iuliae fault (Galli and Naso, in prep); NMFS, northern Matese Mounts faults; UF, Ufita fault; MFS, Mount Marzano fault system; CF, Caggiano fault. This image, with few scattered faults, reflects the poor knowledge concerning seismogenetic structures in this sector of the chain, which is, conversely, affected by strong and frequent earthquakes.
[5 T; >6 PE]. This fault system became known only after the 1980 Irpinia earthquake (Mw=6.9; 3000 casualties), for which it was responsible. It is composed of 3—5 main 310° N normal faults (responsible for the main shock and for the 20-s sub- event). The discontinuous, ~ 35-km-long surface ruptures have been followed in many studies (Bollettinari and Panizza, 1981; Cinque et al., 1981; Westaway and Jackson, 1984, 1987; Pantosti and Valensise, 1990) as this was the first case of surface faulting that was recognized by earthquake geologists in Italy. The fault trace is easily visible on vintage aerial photos since it was mainly carved into Mesozoic carbonate rocks, similar to the central Apennine faults. Moreover, for long segments the fault reverses the present topography, creating uphill-facing scarps; in some places this has produced the damming of local streams and the formation of small marsh-basins. The area crossed by the Mount Marzano fault system has been affected by other two disruptive earthquakes in the past five centuries: the oldest was the 1466 event (Mw=6.6, Galli et al., 2006a), and it was followed by the 1694 one (Mw=6.9; ~ 6000 casualties). Even though both of these events had different geometries and extensions, they shared the same mesoseismic area as the 1980 earthquake. Two distant segments of the structure have been investigated through paleoseismological trenching (Pantosti et al., 1990, 1993; D’Addezio et al., 1991). Two trenches where excavated at Piano di Pecore in the central part of the fault (Fig. 18), and two at Pantano San Gregorio in the southern part of the fault. Four paleoearthquakes were dated by Pantosti et al. (1993), and five by D’Addezio et al. (1991), not including the 1980 one. Combining the results from the two sites, the pre-1980 event occurred between 1415 and 2570 BP, a previous event between 3507 and 4283 BP, with three older ones between 4411-6736 BP, between 6736-8600 BP, and between 11180— 19660 BP. It is thus worth noting that neither the 1466 nor the Fig. 17. View looking ~ south of the Hercules Sanctuary area (Molise, southern Italy). Note the 4th century BC wall and pavement offset by the Bojano fault (normal, with a dextral component). The house was rebuilt after the ~ 280 BC earthquake, leveling the hanging wall sector, and then again faulted (probably in 1456 and 1805). The fault scarp in the original 4th century BC cobbles-pavement has been exhumed by archaeological excavation, while a paleoseismological trench has been dug in the area marked by the arrows (photo by P.G.). The most striking evidence of recent activity of the fault is the oblique (right-lateral) offset of archaeological remains (the Samnitic 4th BC Hercules sanctuary) that were cut by the fault, and which were investigated also by means of a paleoseismic trench dug within the sanctuary area (Fig. 17). Through the archaeologically precise datings of coins, pottery and other findings, the oldest paleoevent recognized was placed at ~280 BC and is unknown to the CPTI04. The remaining offsets of the wall and pavement have been related to both the 1456 and the 1805 surface ruptures. A new trench was excavated across the northern tip of the fault (Mount Patalecchia strand; Blumetti et al., 2000), which also showed evidence of repeated surface faulting across alluvial fan deposits. The oldest event was dated soon after 2838-— 2472 BP, in agreement with the date from Galli and Galadini (2003) of ~280 BC. Thus, the return time for this structure appears to be very irregular, with two events separated by 1.7 kyr and followed by another one 0.3 kyr later.
[5 T; >6 PE]. This fault system became known only after the 1980 Irpinia earthquake (Mw=6.9; 3000 casualties), for which it was responsible. It is composed of 3—5 main 310° N normal faults (responsible for the main shock and for the 20-s sub- event). The discontinuous, ~ 35-km-long surface ruptures have been followed in many studies (Bollettinari and Panizza, 1981; Cinque et al., 1981; Westaway and Jackson, 1984, 1987; Pantosti and Valensise, 1990) as this was the first case of surface faulting that was recognized by earthquake geologists in Italy. The fault trace is easily visible on vintage aerial photos since it was mainly carved into Mesozoic carbonate rocks, similar to the central Apennine faults. Moreover, for long segments the fault reverses the present topography, creating uphill-facing scarps; in some places this has produced the damming of local streams and the formation of small marsh-basins. The area crossed by the Mount Marzano fault system has been affected by other two disruptive earthquakes in the past five centuries: the oldest was the 1466 event (Mw=6.6, Galli et al., 2006a), and it was followed by the 1694 one (Mw=6.9; ~ 6000 casualties). Even though both of these events had different geometries and extensions, they shared the same mesoseismic area as the 1980 earthquake. Two distant segments of the structure have been investigated through paleoseismological trenching (Pantosti et al., 1990, 1993; D’Addezio et al., 1991). Two trenches where excavated at Piano di Pecore in the central part of the fault (Fig. 18), and two at Pantano San Gregorio in the southern part of the fault. Four paleoearthquakes were dated by Pantosti et al. (1993), and five by D’Addezio et al. (1991), not including the 1980 one. Combining the results from the two sites, the pre-1980 event occurred between 1415 and 2570 BP, a previous event between 3507 and 4283 BP, with three older ones between 4411-6736 BP, between 6736-8600 BP, and between 11180— 19660 BP. It is thus worth noting that neither the 1466 nor the Fig. 17. View looking ~ south of the Hercules Sanctuary area (Molise, southern Italy). Note the 4th century BC wall and pavement offset by the Bojano fault (normal, with a dextral component). The house was rebuilt after the ~ 280 BC earthquake, leveling the hanging wall sector, and then again faulted (probably in 1456 and 1805). The fault scarp in the original 4th century BC cobbles-pavement has been exhumed by archaeological excavation, while a paleoseismological trench has been dug in the area marked by the arrows (photo by P.G.). The most striking evidence of recent activity of the fault is the oblique (right-lateral) offset of archaeological remains (the Samnitic 4th BC Hercules sanctuary) that were cut by the fault, and which were investigated also by means of a paleoseismic trench dug within the sanctuary area (Fig. 17). Through the archaeologically precise datings of coins, pottery and other findings, the oldest paleoevent recognized was placed at ~280 BC and is unknown to the CPTI04. The remaining offsets of the wall and pavement have been related to both the 1456 and the 1805 surface ruptures. A new trench was excavated across the northern tip of the fault (Mount Patalecchia strand; Blumetti et al., 2000), which also showed evidence of repeated surface faulting across alluvial fan deposits. The oldest event was dated soon after 2838-— 2472 BP, in agreement with the date from Galli and Galadini (2003) of ~280 BC. Thus, the return time for this structure appears to be very irregular, with two events separated by 1.7 kyr and followed by another one 0.3 kyr later.
Fig. 18. View of one of the trenches excavated in the Piano di Pecore, across the 1980 earthquake fault scarp. The dashed line demonstrates the warping of th palustrine clay and silt (~ 4th millennium BP), which has infilled the small basin dammed by the fault. This sequence records five paleoearthquakes prior to the 198 event, the penultimate of which was probably the 1466 earthquake (photo by D-.P., unpublished data).
Fig. 18. View of one of the trenches excavated in the Piano di Pecore, across the 1980 earthquake fault scarp. The dashed line demonstrates the warping of th palustrine clay and silt (~ 4th millennium BP), which has infilled the small basin dammed by the fault. This sequence records five paleoearthquakes prior to the 198 event, the penultimate of which was probably the 1466 earthquake (photo by D-.P., unpublished data).
Fig. 19. A, one of the trenches excavated across the Caggiano fault, where indications of repeated surface faulting events in the past 7 kyr have been found, amongst which there was the 1561 event. B, view looking NE of the impressive bedrock fault scarp (photos by P.G.). [3 T; 5 PE]. This is the southernmost active fault in the Apennines carbonate chain that has been paleoseismologically investigated; its presence is highlighted by an impressive bedrock scarp along the SW-facing slope of the Mesozoic rocks of Mount San Giacomo (Fig. 19). The structure follows a 120° The data account for several surface faulting events that occurred during the past 7 kyr. Time constrains are available for only some of them: one occurred between 6504-5900 BP, whereas the latest ones occurred in the past 2 kyr BP, and probably during/after slope-debris deposition related to the Little Ice Age (~ 1400-1800 AD). According to Castelli et al.
Fig. 19. A, one of the trenches excavated across the Caggiano fault, where indications of repeated surface faulting events in the past 7 kyr have been found, amongst which there was the 1561 event. B, view looking NE of the impressive bedrock fault scarp (photos by P.G.). [3 T; 5 PE]. This is the southernmost active fault in the Apennines carbonate chain that has been paleoseismologically investigated; its presence is highlighted by an impressive bedrock scarp along the SW-facing slope of the Mesozoic rocks of Mount San Giacomo (Fig. 19). The structure follows a 120° The data account for several surface faulting events that occurred during the past 7 kyr. Time constrains are available for only some of them: one occurred between 6504-5900 BP, whereas the latest ones occurred in the past 2 kyr BP, and probably during/after slope-debris deposition related to the Little Ice Age (~ 1400-1800 AD). According to Castelli et al.
Fig. 20. Shaded relief of Calabria, with primary Late Pleistocene faults (bold indicates certain Holocene active faults; modified from Galli and Scionti, 2006) and major earthquakes (modified after CPTI, 2004; Galli and Molin, 2007). MPF, Mount Pollino and Frascineto faults; RF, Rossano fault; WCFS, western Crati basin fault system; CLF, Cecita lake fault; LF, Lakes fault; SEFF, Sant’Eufemia-Feroleto fault (part of Lamezia-Catanzaro fault Auctorum); NSF, North-Serre fault; SSF, South-Serre fault (Eastern Mesima graben faults); CF, Cittanova (Aspromonte) fault; RCFS, Reggio Calabria fault system (Delianova- Sant’Eufemia-Reggio Calabria and Armo faults). The square symbol is the CPT104 epicenter of the June 1638 event, shifted to the Lakes fault by Galli and Bosi (2003). Note the “seismic gap” in the northern area of the region, where Michetti et al. (1997) and Cinti et al. (2002) hypothesize the occurrence of strong earthquakes caused by the Mount Pollino fault system during historical times. The Tyrrhenian side of Calabria has been struck by the strongest earthquakes of the whole Apennine chain. Among these, the ones characterized by the largest magnitude (M>7) have not been associated with any certain faults yet (e.g., March 1638, March 1783°, 1908; the M,=7.5 1905 earthquake has been tentatively related to slab-bending by Galli and Molin, 2007).
Fig. 20. Shaded relief of Calabria, with primary Late Pleistocene faults (bold indicates certain Holocene active faults; modified from Galli and Scionti, 2006) and major earthquakes (modified after CPTI, 2004; Galli and Molin, 2007). MPF, Mount Pollino and Frascineto faults; RF, Rossano fault; WCFS, western Crati basin fault system; CLF, Cecita lake fault; LF, Lakes fault; SEFF, Sant’Eufemia-Feroleto fault (part of Lamezia-Catanzaro fault Auctorum); NSF, North-Serre fault; SSF, South-Serre fault (Eastern Mesima graben faults); CF, Cittanova (Aspromonte) fault; RCFS, Reggio Calabria fault system (Delianova- Sant’Eufemia-Reggio Calabria and Armo faults). The square symbol is the CPT104 epicenter of the June 1638 event, shifted to the Lakes fault by Galli and Bosi (2003). Note the “seismic gap” in the northern area of the region, where Michetti et al. (1997) and Cinti et al. (2002) hypothesize the occurrence of strong earthquakes caused by the Mount Pollino fault system during historical times. The Tyrrhenian side of Calabria has been struck by the strongest earthquakes of the whole Apennine chain. Among these, the ones characterized by the largest magnitude (M>7) have not been associated with any certain faults yet (e.g., March 1638, March 1783°, 1908; the M,=7.5 1905 earthquake has been tentatively related to slab-bending by Galli and Molin, 2007).
Fig. 21. View looking ~north of one of the trenches excavated on the ~N-S Frascineto faults (Mount Pollino fault system). This and other paleoseismolo- gical trenches showed the late Holocene activity of the structure, which falls within a historical seismic gap.
Fig. 21. View looking ~north of one of the trenches excavated on the ~N-S Frascineto faults (Mount Pollino fault system). This and other paleoseismolo- gical trenches showed the late Holocene activity of the structure, which falls within a historical seismic gap.
Fig. 22. View looking north of one of the trenches dug across the Lakes fault (Sila Massif, Calabria, southern Italy). Arrows point to the fault affecting late Holocene fluvial and colluvial deposits (left) and crystalline rocks (right). This site is a leveled fluvial terrace, and was chosen because it was expected to contain abundant datable material and correlative markers across the fault. The fault displacements dammed up a local stream, inducing a swampy area (clay, bottom-left). The sequence records the June 1638 earthquake, an unknown 7th century AD event, and two other previous ones. (photo by P.G).
Fig. 22. View looking north of one of the trenches dug across the Lakes fault (Sila Massif, Calabria, southern Italy). Arrows point to the fault affecting late Holocene fluvial and colluvial deposits (left) and crystalline rocks (right). This site is a leveled fluvial terrace, and was chosen because it was expected to contain abundant datable material and correlative markers across the fault. The fault displacements dammed up a local stream, inducing a swampy area (clay, bottom-left). The sequence records the June 1638 earthquake, an unknown 7th century AD event, and two other previous ones. (photo by P.G).
Paleoearthquake catalogue of Italy since 19 kyr ago Bold events are those already quoted by the CPTI04. Acronyms in REF (references) include: C, Cinti; D, D’Addezio; Ga, Galadini; G, Galli; Gi, Giraudi; M, Michetti; Mo, Moro; P., Pantosti; S, Salvi; &, et al. Numbers are the year of publication (e.g., G&07=Galli et al., 2007). (1), value associated with the Mount Baldo thrust; (2) value associate with the Lessini fault system. Both | and 2 refer to multiple events (two or more). See text for further details. Table 1
Paleoearthquake catalogue of Italy since 19 kyr ago Bold events are those already quoted by the CPTI04. Acronyms in REF (references) include: C, Cinti; D, D’Addezio; Ga, Galadini; G, Galli; Gi, Giraudi; M, Michetti; Mo, Moro; P., Pantosti; S, Salvi; &, et al. Numbers are the year of publication (e.g., G&07=Galli et al., 2007). (1), value associated with the Mount Baldo thrust; (2) value associate with the Lessini fault system. Both | and 2 refer to multiple events (two or more). See text for further details. Table 1
Fig. 24. Plot of fault length (km) against magnitude (Mw) for the few, availabl Italian cases.
Fig. 24. Plot of fault length (km) against magnitude (Mw) for the few, availabl Italian cases.
Fig. 25. A, plot of all of the paleoearthquakes reported in the PCI. Error bars indicate the time span within which each single event should have occurred (see Table 1); error scale (in kyr) can be read on the right axis. B, plot of earthquakes with Mw = 6.5 currently reported in the CPTI (note that A and B have different time windows). It has also been demonstrated that although complete, the historical record is much shorter than the recurrence time of the largest earthquakes; therefore, it under-represents the long-term, average seismic moment rates (Ward, 1998), and possibly the seismic potential of a region (Jenny et al., 2006). By including the paleoearthquakes in the seismic catalogue, the lower boundaries of the regional seismic strain rates would probably be shifted (but not necessary raised) towards more realistic values, making geologic, geodetic and seismic data more comparable (e.g., Ward, 1998; Selvaggi, 1998; Montone et al., 2004; Pondrelli et al., 2006; Serpelloni et al., 2005). Actually, while there are many geological and geophysical approaches for investigating whether a fault was active in Quaternary times (or during the Late Pleistocene), in many situations, the paleoseismological approach can definitively show whether this fault is currently active, and what its seismic
Fig. 25. A, plot of all of the paleoearthquakes reported in the PCI. Error bars indicate the time span within which each single event should have occurred (see Table 1); error scale (in kyr) can be read on the right axis. B, plot of earthquakes with Mw = 6.5 currently reported in the CPTI (note that A and B have different time windows). It has also been demonstrated that although complete, the historical record is much shorter than the recurrence time of the largest earthquakes; therefore, it under-represents the long-term, average seismic moment rates (Ward, 1998), and possibly the seismic potential of a region (Jenny et al., 2006). By including the paleoearthquakes in the seismic catalogue, the lower boundaries of the regional seismic strain rates would probably be shifted (but not necessary raised) towards more realistic values, making geologic, geodetic and seismic data more comparable (e.g., Ward, 1998; Selvaggi, 1998; Montone et al., 2004; Pondrelli et al., 2006; Serpelloni et al., 2005). Actually, while there are many geological and geophysical approaches for investigating whether a fault was active in Quaternary times (or during the Late Pleistocene), in many situations, the paleoseismological approach can definitively show whether this fault is currently active, and what its seismic
Fig. 26. A, extension direction within the Apennine chain given by the kinematics and attitude of all of the paleoseismologically investigated faults (i.e., all normal o: slightly transtensional), coupled with GPS-derived average extensional rates (from strain-rate values calculated within GPS subnetworks; E. Serpelloni, unpublishec data). Arrows are invariant with rates. B, available CMT for the same area (1976—2006; modified from Pondrelli et al., 2006). Note that all of the dataset, each piece o: which covers a different time span, shows coherent NE—SW extensions along the Apennine chain, ~ N—S in northern Calabria, and NW-SE in southern Calabria- Messina Straits.
Fig. 26. A, extension direction within the Apennine chain given by the kinematics and attitude of all of the paleoseismologically investigated faults (i.e., all normal o: slightly transtensional), coupled with GPS-derived average extensional rates (from strain-rate values calculated within GPS subnetworks; E. Serpelloni, unpublishec data). Arrows are invariant with rates. B, available CMT for the same area (1976—2006; modified from Pondrelli et al., 2006). Note that all of the dataset, each piece o: which covers a different time span, shows coherent NE—SW extensions along the Apennine chain, ~ N—S in northern Calabria, and NW-SE in southern Calabria- Messina Straits.
Related topics:
Geomorphology and Active tectonicsActive TectonicsEarthquake Seismology
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved