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Coseismic and postseismic displacements related with the 1997 earthquake sequence in Umbria-Marche (central Italy)
Language
English
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
14/28 (2001)
Publisher
American Geophysical Union
Pages (printed)
2695–2698
Issued date
February 2001
Alternative Location
Subjects
Abstract
We study the coseismic and postseismic displacements related with the 1997 Umbria-Marche earthquake sequence by means of leveling lines along a deformed aqueduct located in the epicentral area. Comparing the 1960 and 10/1997 measurements we obtain 0.49 0.10 m of coseismic displacement distributed along 3 km across the normal fault zone. Modeling of the coseismic surface dislocation is obtained from a combination of low angle (38°) faults at depth and high angle (80°) upper fault branches. The best fit model indicates that the upper branches stop at 0.4 km below the ground surface and have 60% of slip with respect to the lower faults. The postseismic displacement measured during 1998 is 0.18 m and represents 36% of the apparent coseismic deformation. Moderate earthquakes in the Apennines and related surface deformation may thus result from curved faults that reflect the brittle-elastic properties of the uppermost crustal structures.
Sponsors
Data collection was made while both authors were at Istituto di Ricerca per la Tettonica Recente – CNR (GNDT Project), Roma, Italy. M. Copparoni (ASM, Foligno) and M. Raponi and S. Pacico (Studio Topografico s.n.c., Foligno) provided data about aqueduct and leveling lines. Analysis of data and modeling were done while RB was visiting EOST-IPG, Strasbourg, France. Preparation of the paper benefited from discussion with R. Armijo, S. Barba, P. Gomez and G. Valensise. A. Amato and an anonymous reviewer are thanked for their constructive remarks.
References
Amato, A., and 18 others (1998) The 1997 Umbria-Marche, Italy, earthquake sequence: a first look at main shocks and aftershocks. Geophys. Res. Lett., 25, 2861-2864.
Barba, S., and R. Basili (2000) Analysis of seismological and geological observations for moderate size earthquakes: the Colfiorito Fault System (Central Apennines, Italy). Geophys. J. Int., 141, 241-252.
Basili, R., V. Bosi, F. Galadini, P. Galli, M. Meghraoui, P. Messina, M. Moro and A. Sposato (1998) The Colfiorito earthquake sequence of September-October 1997: Surface breaks and seismotectonic implications for the central Apennines (Italy). J. Earthquake Engrg., 2, 291-302.
Bray, J. D., R. B. Seed and H. B. Seed (1994) Analysis of earthquake fault rupture propagation through soil. J. Geotech. Engrg., 120, 562-580.
De Martini, P. M., and G. Valensise (1999) Pre-seismic slip on the 26 September 1997, Umbria-Marche earthquake fault? Unexpected clues from the analysis of 1951-1992 elevation changes. Geophys. Res. Lett., 26, 1953-1956.
Ekström, G., A. Morelli, A. M. Dziewonski and E. Boschi (1998) Moment tensor analysys of the Umbria-Marche earthquake sequence of September-October 1997. Geophys. Res. Lett., 25, 1971-1974.
Feigl, K. L., and E. Dupré (1999) RNGCHN: a program to calculate displacement components from dislocations in an elastic half-space with applications for modeling geodetic measurements of crustal deformation. Computer & Geosciences, 25, 695-704.
Hunstad, I., M. Anzidei, M. Cocco, P. Baldi, A. Galvani and A. Pesci (1999) Modelling coseismic displacements during the 1997 Umbria-Marche earthquake (central Italy). Geophys. J. Int., 139, 283-295.
Liu, H. P., R. L. Hagman and R. F. Scott (1978) Centrifuge modeling of earthquakes. Geophys. Res. Lett., 5, 333-336.
Meghraoui, M., V. Bosi and T. Camelbeeck (1999) Fault fragment control in the 1997 Umbria-Marche, central Italy, earthquake sequence. Geophys. Res. Lett., 26, 1069-1072.
Mooney, W., G. Laske and T. G. Masters (1998) CRUST 5.1: A global crustal model at 5°x5°. J. Geophys. Res., 103 B1, 727-747.
Okada, Y. (1985) Surface deformation due to shear and tensile faults in a half-space. Bull. Seism. Soc. Am., 75, 1135-1154.
Salvi, S., and 13 others (2000) Modeling coseismic displacements resulting from SAR interferometry and GPS measurements during the 1997 Umbria-Marche seismic sequence. Journ. of. Seismology, special volume, 4, 479-499.
Stein, R. S., and M. Lisowsky (1983) The 1979 Homestead Valley earthquake sequence, California: control of aftershocks and postseismic deformation. J. Geophys. Res., 88 B8, 6477-6490.
Stramondo, S., and 12 others (1999) The September 26, 1997 Colfiorito, Italy, earthquakes: modeled coseismic surface displacement from SAR interferometry and GPS. Geophys. Res. Lett., 26, 883-886.
Withjack, M. O., J. Olson and E. Peterson (1990) Experimental models of extensional forced folds. AAPG Bull., 74, 1038-1054.
Zollo, A., S. Marcucci, G. Milana and P. Capuano (1999) The 1997 Umbria-Marche (Central Italy) earthquake sequence: Insights on the mainshock ruptures from near source strong motion records. Geophys. Res. Lett., 26, 3165-3168.
Barba, S., and R. Basili (2000) Analysis of seismological and geological observations for moderate size earthquakes: the Colfiorito Fault System (Central Apennines, Italy). Geophys. J. Int., 141, 241-252.
Basili, R., V. Bosi, F. Galadini, P. Galli, M. Meghraoui, P. Messina, M. Moro and A. Sposato (1998) The Colfiorito earthquake sequence of September-October 1997: Surface breaks and seismotectonic implications for the central Apennines (Italy). J. Earthquake Engrg., 2, 291-302.
Bray, J. D., R. B. Seed and H. B. Seed (1994) Analysis of earthquake fault rupture propagation through soil. J. Geotech. Engrg., 120, 562-580.
De Martini, P. M., and G. Valensise (1999) Pre-seismic slip on the 26 September 1997, Umbria-Marche earthquake fault? Unexpected clues from the analysis of 1951-1992 elevation changes. Geophys. Res. Lett., 26, 1953-1956.
Ekström, G., A. Morelli, A. M. Dziewonski and E. Boschi (1998) Moment tensor analysys of the Umbria-Marche earthquake sequence of September-October 1997. Geophys. Res. Lett., 25, 1971-1974.
Feigl, K. L., and E. Dupré (1999) RNGCHN: a program to calculate displacement components from dislocations in an elastic half-space with applications for modeling geodetic measurements of crustal deformation. Computer & Geosciences, 25, 695-704.
Hunstad, I., M. Anzidei, M. Cocco, P. Baldi, A. Galvani and A. Pesci (1999) Modelling coseismic displacements during the 1997 Umbria-Marche earthquake (central Italy). Geophys. J. Int., 139, 283-295.
Liu, H. P., R. L. Hagman and R. F. Scott (1978) Centrifuge modeling of earthquakes. Geophys. Res. Lett., 5, 333-336.
Meghraoui, M., V. Bosi and T. Camelbeeck (1999) Fault fragment control in the 1997 Umbria-Marche, central Italy, earthquake sequence. Geophys. Res. Lett., 26, 1069-1072.
Mooney, W., G. Laske and T. G. Masters (1998) CRUST 5.1: A global crustal model at 5°x5°. J. Geophys. Res., 103 B1, 727-747.
Okada, Y. (1985) Surface deformation due to shear and tensile faults in a half-space. Bull. Seism. Soc. Am., 75, 1135-1154.
Salvi, S., and 13 others (2000) Modeling coseismic displacements resulting from SAR interferometry and GPS measurements during the 1997 Umbria-Marche seismic sequence. Journ. of. Seismology, special volume, 4, 479-499.
Stein, R. S., and M. Lisowsky (1983) The 1979 Homestead Valley earthquake sequence, California: control of aftershocks and postseismic deformation. J. Geophys. Res., 88 B8, 6477-6490.
Stramondo, S., and 12 others (1999) The September 26, 1997 Colfiorito, Italy, earthquakes: modeled coseismic surface displacement from SAR interferometry and GPS. Geophys. Res. Lett., 26, 883-886.
Withjack, M. O., J. Olson and E. Peterson (1990) Experimental models of extensional forced folds. AAPG Bull., 74, 1038-1054.
Zollo, A., S. Marcucci, G. Milana and P. Capuano (1999) The 1997 Umbria-Marche (Central Italy) earthquake sequence: Insights on the mainshock ruptures from near source strong motion records. Geophys. Res. Lett., 26, 3165-3168.
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