Istituto nazionale di geofisica e vulcanologia
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Individual Seismogenic Sources

General information
ITIS066
Orciano Pisano
Vannoli P.(1)
Vannoli P.(1)
1) Istituto Nazionale di Geofisica e Vulcanologia; Sismologia e Tettonofisica; Via di Vigna Murata, 605, 00143 Roma, Italy
08-Nov-2005
08-Nov-2005
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Parametric information
ParameterQualityEvidence
43.52 / 10.49 OD Based on macroseismic and geological data.
7.9 ER Calculated using the relationships from Wells and Coppersmith (1994).
6.4 ER Calculated using the relationships from Wells and Coppersmith (1994).
2.0 EJ Inferred from geological observations.
6.9 EJ Inferred from geological observations.
337 EJ Inferred from geological data.
50 EJ Inferred from geological data.
270 EJ Inferred from geological data.
0.3 ER Calculated from Mo using the relationship from Hanks and Kanamori (1979).
0.1…1.0 EJ Unknown, values assumed from geodynamic constraints.
300…3000 EJ Inferred from slip rate and average displacement.
5.7 LD Value adopted from the historical earthquake catalogue CPTI04.
LD=Literature Data; OD=Original Data; ER=Empirical Relationship; AR=Analytical Relationship;EJ=Expert Judgement;
 
Information about the associated Earthquakes
14 Aug 1846 CPTI04.
Unknown See "Commentary" for information.
 
 
Active Faults
Active Folds
Commentary

 

 COMMENTS

We propose the existence of this Source based on the recent tectonic activity of the inner Northern Apennines and on the occurrence of the 14 August 1846 earthquake.

The internal (and western) portion of the chain is traditionally considered an area bearing major extensional tectonics that have affected the pre-existing compressional structures of the inner Northern Apennines. Two extensional stages have been recognized in the Tertiary evolution of the Tuscany region. The first tectonic phase has occurred between the Late Oligocene and Late Tortonian and caused a stretching of 120% or greater. The second phase has occurred between the Late Tortonian and Quaternary time. The main result of the second extensional phase is represented by high-angle normal faults which dissect all previous structures. These faults border the NW-SE trending horst and graben that developed during the late Miocene-Pleistocene (e.g. Carmignani et al., 1994, 2001).

According to this view, most of the regional deformation would be exerted by a few extensional fault systems responsible for the large scale landscape features of the inner Northern Apennines. Instrumental catalogues show a seismic sequence (with max Mw of 4.2) that hit the offshore area located about 15 km west of the Orciano Pisano source in April 1984 (Castello et al., 2006). Out of the sequence, the 22 April 1984 earthquake, showing a normal fault plane solution (Pondrelli et al., 2006) with two conjugate NNW-SSE planes, can help defining the seismotectonics of the area.

In Tuscany, reflection seismic data have revealed a regional reflector referred to as the K-horizon (Batini et al., 1978), a layer of fractured rocks hosting high-pressure fluids that usually coincides with the top of the crustal brittle-ductile transition, which ranges in depth between 4 and 9 km (Cameli et al., 1998).

We propose the following geometrical parameters for the source:

  • the strike is chosen according to that of the T. Tora valley, at the northern end of the well-known Val di Fine graben;
  • the fault dips towards the East, according to the main axis of the 1846 earthquake macroseismic pattern;
  • the rake is assumed to be pure normal faulting, based on geodynamic considerations constrained by mesostructures affecting recent deposits of the area;
  • maximum depth is constrained by the K-horizon;
  • length and width are constrained by scaling relationships with the 1846 earthquake magnitude.

This Source is associated with the 14 August 1846 earthquake (Mw 5.7) reported by CPTI (2004) and having its epicentral area between Orciano Pisano, Lorenzana, and Fauglia. Our source model is well consistent with the highest damage of the earthquake, and with the possible surface expression identified at the base of the eastern slope of the Livorno Hills (Piccardi et al., 2017).

OPEN QUESTIONS

1) What is the average return period of this Source?

2) Is this Source a normal fault?

 
Pictures

 

Heat flow, hot springs and gas emissions Details
Location of Plio-Quaternary basins, gas vents and associated waters Details
Distribution of the post-orogenic basins Details
Active faults and perspective view of the Orciano Pisano fault Details
References

 

Ambrosetti, P., M. G. Carboni, M. A. Conti, A. Costantini, D. Esu, A. Gadin, O. Girotti, A. Lazzarotti, R. Mazzanti, U. Nicosia, G. Parisi and F. Sandrelli 1978 Evoluzione paleogeografica e tettonica dei bacini tosco-umbro-laziali nel Pliocene e nel Pleistocene inferiore. Mem. Soc. Geol. It., 19, 573-580.
Bartole, R. 1995 The North Tyrrhenian-Northern Apennines post-collisional system: constraints for geodinamic model. Terra Nova, 7, 7-30.
Bartolini, C., M. Bernini, G. C. Carloni, A. Costantini, P. R. Federici, G. F. Gasperi, A. Lazzarotto, M. Marchetti, R. Mazzanti, G. Papani, G. Pranzini, A. Rau, F. Sandrelli, P. L. Vercesi, D. Castaldini and F. Francavilla 1982 Carta neotettonica dell’Appennino Settentrionale. Note illustrative. Boll. Soc. Geol. It., 101, 523-549.
Batini, F, P. D. Burgassi, G. M. Cameli, R. Nicolich and P. Squarci 1978 Contribution to the study of the deep lithospheric profiles: Deep reflecting horizons in Larderello-Travale Geothermal field. Mem. Soc. Geol. It., 19, 477-484.
Bellani, S., A. Brogi, A. Lazzarotto, D. Liotta and G. Ranalli 2004 Heat flow, deep temperatures and extensional structures in the Larderello Geothermal Field (Italy): constraints on geothermal fluid flow. J. Volcanol. Geoth. Res., 132, 15-29.
Boccaletti, M., and F. Sani 1998 Cover thrust reactivations related to internal basement involvement during Neogene-Quaternary evolution of the northern Apennines. Tectonics, 17, 112-130.
Boccaletti, M., M. Coli, C. Eva, G. Ferrari, G. Giglia, A. Lazzarotto, F. Merlanti, R. Nicolich, G. Papani and D. Postpischl 1985 Considerations on the seismotectonics of the Northern Apennines. Tectonophysics, 117, 7-38.
Bortolotti, V. 1966 La tettonica trasversale dell'Appennino. La linea Livorno-Sillaro. Boll. Soc. Geol. It., 85, 529-540.
Bossio, A., A. Costantini, L. M. Foresi, A. Lazzarotto, R. Mazzanti, R. Mazzei, V. Pascucci, G. Salvatorini, F. Sandrelli and A. Terzuoli 1998 Space-time sedimentary evolution of the Neogene-Quaternary sediments of the western side of the Northern Apennines (Italy). Mem. Soc. Geol. It., 52, 513-525.
Bossio, A., R. Cerri, A. Costantini, A. Gandin, A. Lazzarotto. M. Magi, R. Mazzanti, R. Mazzei, M. Sagri and G. Salvatorini 1992 I bacini distensivi neogenici e quaternari della Toscana. 76a Adunanza Estiva Soc. Geol. It., Guida alle escursioni, Firenze.
Cameli, G. M., I. Dini and D. Liotta 1998 Brittle/ductile boundary from seismic reflection lines of southern Tuscany (Northern Apennines, Italy). Mem. Soc. Geol. It., 52, 153-163.
Carmignani, L., F. A. Decandia, L. Disperati, P. L. Fantozzi, R. Kligfield, A. Lazzarotto, D. Liotta and M. Meccheri 2001 Inner Northern Apennines. in: G. B. Vai and I. P. Martini (eds), Anatomy of an Orogen: the Apennines and Adjacent Mediterranean Basins. Kluwer Academic Publishers, Dordrecht, 2001, 197-214.
Carmignani, L., F. A. Decandia, P. L. Fantozzi, A. Lazzarotto, D. Liotta and M. Meccheri 1994 Tertiary extensional tectonics in Tuscany (Northern Apennines, Italy). Tectonophysics, 238, 295-315.
Castello, B., G. Selvaggi, C. Chiarabba and A. Amato 2006 CSI Catalogo della sismicità italiana 1981-2002, versione 1.1. INGV-CNT, Roma, http://www.ingv.it/CSI/.
Costantini, A., A. Lazzarotto, and F. Sandrelli 1982 Conoscenze geologico strutturali. In: Il graben di Siena. C.N.R. Progetto finalizzato energetica, sottoprogetto energia geotermica, RF-9, 11-34.
D'Agostino, N., and G. Selvaggi 2004 Crustal motion along the Eurasia-Nubia plate boundary in the Calabrian Arc and Sicily and active extension in the Messina Straits from GPS measurements. J. Geophys. Res., 109, B11402, 10.1029/2004JB002998.
Elter, P., G. Giglia, M. Tongiorgi and L. Trevisan 1975 Tensional and compressional areas in the recent (Tortonian to present) evolution of the Northern Apennines. Boll. Geof. Teor. Appl., 17, 3-18.
Giannini, E. 1955 Osservazioni sulla geologia del bacino della Fine e delle colline fra Rosignano Marittimo e la Valle della Cecina. Boll. Soc. Geol. It., 74, 297-316.
Heidbach, O., M. Tingay, A. Barth, J. Reinecker, D. Kurfeß, and B. Müller 2008 The world stress map database release 2008. 10.1594/GFZ.WSM.Rel2008.
Liotta, D., and G. Ranalli 1999 Correlation between seismic reflectivity and rheology in extended lithosphere: Southern Tuscany, inner northern Apennines, Italy. Tectonophysics, 315, 109-122.
Martini, I. P., and M. Sagri 1993 Tectono-sedimentary characteristics of Late Miocene-Quaternary extensional basins of the Northern Apennines, Italy. Earth-Sci. Rev., 34, 197-233.
Minissale, A., G. Magro, G. Martinelli, O. Vaselli and G. F. Tassi 2000 Fluid geochemical transect in the Northern Apennines (central-northern Italy): fluid genesis and migration and tectonic implications. Tectonophysics, 319, 199-222.
Pascucci, V. 1997 Seismic comparative study of an onshore and offshore basin of Tuscany and Tuscan Shelf (Italy). Giorn. Geol., 59, 289-300.
Patacca, E., R. Sartori and P. Scandone 1990 Tyrrhenian basin and Apenninic Arcs: Kinematic relations since Late Tortonian times. Mem. Soc. Geol. It., 45, 425-451.
Piccardi, L., E. Vittori, A. M. Blumetti, V. Comerci, P. Di Manna, L. Guerrieri, M. Baglione, and V. D'Intinosante 2017 Mapping capable faulting hazard in a moderate-seismicity, high heat-flow environment: The Tuscia province (southern Tuscany-northern Latium, Italy). Quatern. Int., 451, Supplement C, 11-36, https://doi.org/10.1016/j.quaint.2017.07.018.
Pilla, L. 1846 Istoria del tremuoto che ha devastato i paesi della costa toscana il dì 14 agosto 1846. R. Vannucchi, Pisa.
Pilla, L. 1846 Poche parole sul tremuoto che ha desolato i paesi della costa toscana. R. Vannucchi, Pisa.
Pondrelli, S., S. Salimbeni, G. Ekström, A. Morelli, P. Gasperini and G. Vannucci 2006 The Italian CMT dataset from 1977 to the present. Phys. Earth Planet. In., 159, 286-303.
Savi, P. 1846 Relazione de' fenomeni presentati dai terremoti di Toscana dell'agosto 1846 e considerazioni teoretiche sopra i medesimi. Tipografia Nistri, Pisa.
Tabani, G. 1846 Del terremoto accaduto in Toscana il 14 agosto 1846. Narrazione storica. Tipografia Nistri, Pisa.
Zitellini, N., F. Tricardi, M. Marani and A. Fabbri 1986 Neogene tectonics of the Northern Tyrrhenian sea. Giorn. Geol., 48, 25-40.
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