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Journal of Seismology

, Volume 4, Issue 4, pp 479–499 | Cite as

Modeling coseismic displacements resulting from SAR interferometry and GPS measurements during the 1997 Umbria-Marche seismic sequence

  • S. Salvi
  • S. Stramondo
  • M. Cocco
  • M. Tesauro
  • I. Hunstad
  • M. Anzidei
  • P. Briole
  • P. Baldi
  • E. Sansosti
  • G. Fornaro
  • R. Lanari
  • F. Doumaz
  • A. Pesci
  • A. Galvani
Article

Abstract

In this study we analyse coseismic GPS displacements and DInSAR data to constrain a dislocation model for the three largest earthquakes of the 1997 Umbria-Marche seismic sequence. The first two events, which occurred on September 26 at 00:33 GMT (Mw 5.7) and 09:40 GMT (Mw 6.0) respectively, are investigated using both GPS displacements and DInSAR interferograms. We discuss and compare the results of previous studies which separately modeled a smaller subset of geodetic data. We provide a dislocation model for these two earthquakes which fits well both GPS and DInSAR data and agrees with the results of seismological and geological investigations. The first event consists of a unilateral rupture towards the southeast with a uniform dislocation. The strike, rake and dip angles are those resulting from the CMT solution. The second event consists of an unilateral rupture towards the northwest and a variable slip distribution on the fault plane. The strike and the rake are consistent with the CMT solution, but the dip angle has been slightly modified to improve the simultaneous fit of GPS and DInSAR data. While the second rupture (09:40 GMT) arrived very close to the surface, the fit to geodetic data shows that the first rupture (00:33 GMT) is deeper (2 km), despite the more evident surface geological effects. The analysis of new SAR interferograms allows the identification of a 5–6 cm additional displacement caused by the October 3 (Mw 5.2) and 6 (Mw 5.4) seismic events.We use data from a new DInSAR interferogram to model the displacement field of the Sellano earthquake of October 14, 1997. For this event significant GPS measurements were not available. We tested two different fault plane geometries: a blind, planar fault (top depth = 2.4 km), and a curved (listric) fault reaching the surface. The two models provide a generally similar fit to the data, and show that most of the slip was released at depths greater than 2.4 km along a gently dipping (40°–45°) fault surface. They also show that a unilateral rupture does not allow fitting the interferometric fringes since there is evident surface deformation to the northwest of the hypocenter. Moreover, we suggest that the concentration of high residuals in the southern part of our uniform slip model may in fact indicate a certain slip variability in this area.We conclude that, despite the moderate magnitudes and the lack of significant surface faulting, the space geodetic data allowed to constrain dislocation models giving new insights in the rupture process of the three largest events of the sequence.

coseismic displacement dislocation models earthquake faulting GPS measurements SAR interferometry 

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References

  1. Amato, A., Azzara, R., Chiarabba, C., Cimini, G.B., Cocco, M., Di Bona, M., Margheriti, L., Mazza, S., Mele, F., Selvaggi, G., Basili, A., Boschi, E., Courboulex, F., Deschamps, A., Gaffet, S., Bittarelli, G., Chiaraluce, L., Piccinini, D. and Ripepe, M., 1998, The 1997 Umbria-Marche, central Italy earthquake sequence: a first look at main shocks and aftershocks, Geophys. Res. Lett. 25(15), 2861–2864.Google Scholar
  2. Anzidei, M., Baldi, P., Coticchia, A., Del Mese, S., Galvani, A., Hunstad, I., Pesci, A., Pierozzi, M., Surace, L. and Zanutta, A., 1998, Utilizzo della rete GPS IGM95 per lo studio delle deformazioni cosismiche dei terremoti umbro-marchigiani del 26 settembre 1997, Bollettino di Geodesia e Scienze Affini 3, 325–335.Google Scholar
  3. Basili, R., Bosi, V., Galadini, F., Galli, P., Meghraoui, M., Messina, P., Moro, M. and Sposato, A., 1998, The Colfiorito earthquake sequence of September-October 1997: Surface breaks and seismotectonic implications for the central Apennines (Italy), J. Earthquake Eng. 2, 291–302.Google Scholar
  4. 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, Book edited by the Istituto Nazionale di Geofisica, Rome, 973 pp.Google Scholar
  5. Capuano, P., Zollo, A., Emolo, A., Marcucci, S. and Milana, G., 1999, Rupture mechanism and source parameters of Umbria-Marche mainshocks from strong motion data, Journ. of Seism., (this volume).Google Scholar
  6. Cattaneo, M., Augliera, P., De Luca, G., Gorini, A., Govoni, A., Marcucci, S., Michelini, A., Monachesi, G., Spallarossa, D., Trojani, L. and XGUMS, 1999, The 1997 Umbria-Marche (Italy) earthquake sequence: analysis of the data recorded by the local and temporary networks, Journ. of Seism., (this volume).Google Scholar
  7. Cello G., Deiana, G., Ferreli, L., Marchegiani, L., Maschio, L., Mazzoli, S., Michetti, A., Serva, L., Tondi, E. and Vittori, T., 1999, Geological constraints for earthquake faulting analysis in the Colfiorito area, Journ. of Seism., (this volume).Google Scholar
  8. Cello, G., Mazzoli, S., Tondi, E. and Turco, E., 1997, Active tectonics in the Central Apennines and possible implication for seismic hazard analysis in peninsular Italy, Tectonophysics 272, 43–60.Google Scholar
  9. Cello, G., Deiana, G., Mangano, P., Mazzoli, S., Tondi, E., Ferreli, L., Maschio, L., Michetti, A.M., Serva, L. and Vittori, E., 1998, Evidence for surface faulting during the September 26, 1997, Colfiorito (Central Italy) Earthquakes, J. Earthquake Engineering 2, 303–324.Google Scholar
  10. Cinti, F.R., Cucci, L., Marra, F. and Montone, P., 1999, The 1997 Umbria-Marche (Italy) earthquake sequence: relationship between ground deformation and seismogenic structure, Geophys. Res. Lett. 26, 895–898.Google Scholar
  11. Cinti F.R., Cucci, L., Marra, F. and Montone, P., 1999, Surface tectonic effects vs seismological data of 1997 Umbria-Marche earthquakes (Italy), Journ. of Seism., (this volume).Google Scholar
  12. De Martini, P.M. and Valensise, G., 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. Letters., (in press).Google Scholar
  13. Deschamps, A. et al., 1999, Spatio-temporal distribution of seismic activity during the Umbria-Marche crisis, 1997, Journ. of Seism., (this volume).Google Scholar
  14. Deschamps, A., Iannaccone, G. and Scarpa, R., 1984, The Umbrian earthquake (Italy) of 19 September 1979, Annales Geophysicae 2(1), 29–36.Google Scholar
  15. Ekström, E., Morelli, A., Boschi, E. and Dziewonski, A.M., 1998, Moment tensor analysis of the Central Italy earthquake sequence of September-October 1997, Geophys. Res. Lett. 25, 1971–1974.Google Scholar
  16. Fornaro, G., Franceschetti, G., Lanari, R., Rossi, D. and Tesauro, M., 1997, nterferometric SAR phase unwrapping via the Finite Element Method, Proceedings of the IEEE Part F, 144, 266–274.Google Scholar
  17. Galli, P. and Galadini, F., 1999, Seismotectonic framework of the 1997- 1998 Umbria-Marche (Central Italy) carthquakes, Seism. Res. Letters. 70(4), 417–427.Google Scholar
  18. Haessler, H., Gaulon, R., Rivera, L., Console, R., Frogneux, M., Gasparini, C., Martel, L., Patau, G., Siciliano, M. and Cisternas, A., 1988, The Perugia (Italy) earthquake of 29 April 1984: a microearthquake survey, Bull. Seism. Soc. Am. 78(6), 1948–1964.Google Scholar
  19. Hunstad, I., Anzidei, M., Cocco, M., Baldi, P., Galvani, A. and Pesci, A., 1999, Modelling coseismic displacement during the 1997 Umbria-Marche earthquake (Central Italy), Geoph. Journ. Inter., (accepted).Google Scholar
  20. Massonnet, D., Rossi, M., Carmona, C., Adragna, F., Peltzer, G., Feigl, K. and Rabaute, T., 1993a, The displacement field of the Landers earthquake mapped by radar interferometry, Nature 364, 138–142.Google Scholar
  21. Massonnet, D., Rabaute, T., Radar Interferometry: limits and potential, 1993b, IEEE Trans. On Geosci. and Remote Sensing 31(2), 455–464.Google Scholar
  22. Massonnet, D., Thatcher, W. and Vadon, H., 1996, Detection of postseismic fault-zone collapse following the Landers earthquake, Nature 382, 612–616.Google Scholar
  23. Massonnet, D. and Feigl, K., 1998, Radar interferometry and its applications to the changes in the Earth's surface, Reviews of Geophysics 36, 441–500.Google Scholar
  24. Murakami, M., Tobita, M., Fujiwara, S., Saito, T. and Masaharu, H., 1996, Coseismic crustal deformations of the 1994 Northridge, California, earthquake detected by interferometric JERS 1 synthetic aperture radar, J. Geophys. Res. 101(B4), 8605–8614.Google Scholar
  25. Okada, Y., 1985, Surface deformations due to shear and tensile faults in a half-space, Bull. Seism. Soc. Am. 75, 1135–1154.Google Scholar
  26. Olivieri, M. and Ekström, E., 1999, Rupture depths and source processes of the 1997- 1998 earthquake sequnce in Central Italy, Bull. Seism. Soc. Am. 89(1), 305–310.Google Scholar
  27. Peltzer, G. and Rosen, P., 1995, Surface displacement of the 17 May 1993 Eureka Valley, California, earthquake observed by SAR interferometry, Science 268, 1333–1336.Google Scholar
  28. Pino, N.A., Mazza, S. and Boschi, E., 1999, Rupture directivity of the major shocks in the 1997 Umbria-Marche (Central Italy) sequence from regional broadband waveforms, Geophys. Res. Lett. 26, 2101–2104.Google Scholar
  29. Pino, N.A. and Mazza, S., 1999, The Umbria-Marche (Central Italy) earthquakes: relation between rupture directivity and sequence evolution for the Mw > 5 shocks, Journ. of Seism., (this volume).Google Scholar
  30. Stramondo, S., Tesauro, M., Briole, P., Sansosti, E., Salvi, S., Lanari, R., Anzidei, M., Baldi, P., Fornaro, G., Avallonc, A., Buongiorno, M.F., Franceschetti, G. and Boschi, E., 1999, The September 26, 1997 Colfiorito, Italy, earthquakes: modeled coseismic surface displacement from SAR interferometry and GPS, Geophys. Res. Lett. 26(7), 883–886.Google Scholar
  31. Surace, L., 1993, Il progetto IGM95, Bollettino di Geodesia e Scienze Affini 3, 220–230.Google Scholar
  32. Surace, L., 1997, La nuova rete geodetica nazionale IGM95: risultati e prospettive di applicazione, Bollettino di Geodesia e Scienze Affini 3, 357–377.Google Scholar
  33. Wells, D.L. and Coppersmith, K.J., 1994, New empirical relationships among magnitude, Rupture length, rupture width, rupture area and surface displacement, Bullettin of the Seismological Society of America 84(4), 974–1002.Google Scholar
  34. Wright, T., Parsons, B., Jackson, J., Haynes, M., Fielding, E., England, P. and Clarke, P., 1999, Source parameters of the 1 October 1995 Dinar (Turkey) earthquake from SAR interferometry and seismic body wave modelling, Abstract of FRINGE '99 ESA workshop, Liege, Belgium.Google Scholar

Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • S. Salvi
    • 1
  • S. Stramondo
    • 1
  • M. Cocco
    • 1
  • M. Tesauro
    • 2
  • I. Hunstad
    • 1
  • M. Anzidei
    • 1
  • P. Briole
    • 3
  • P. Baldi
    • 4
  • E. Sansosti
    • 2
  • G. Fornaro
    • 2
  • R. Lanari
    • 2
  • F. Doumaz
    • 1
  • A. Pesci
    • 1
  • A. Galvani
    • 1
  1. 1.Istituto Nazionale di GeofisicaRomeItaly
  2. 2.CNR-IRECENaplesItaly
  3. 3.Institute de Physique du GlobeParisFrance
  4. 4.Università di BolognaBolognaItaly

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