pure and applied geophysics

, Volume 144, Issue 2, pp 277–300 | Cite as

Possible creep-related tilt precursors obtained in the Central Apennines (Italy) and in the Southern Caucasus (Georgia)

  • F. Bella
  • P. F. Biagi
  • M. Caputo
  • G. Della Monica
  • A. Ermini
  • P. V. Manjgaladze
  • V. Sgrigna
  • D. O. Zilpimiani
Article

Abstract

Daily averaged tilt component data from two sites of the Central Apennines (Italy) and of the Southern Caucasus (Georgia), respectively, revealed intermediate-term tilts as possible precursors to earthquakes (M=3.0÷4.7) which occurred in the above-mentioned seismic areas within a distance of 50 km from the sites. A good temporal correlation as well as a fair spatial correspondence between these residual tilts (with amplitude and duration of some microradians and months, respectively) and main shocks were pointed out, by removing both secular trends and seasonal thermoelastic effects from the raw tilts. An attempt was made to justify the above-mentioned results, based on the assumption that the observed intermediate-term preseismic tilts are the manifestation of aseismic creep episodes of comparable duration in the fault materials of thrust faults close to the tilt sites. The mechanism refers to a strain field slowly propagating from the preparation focal area to the tilt site, through crustal blocks separated by weak transition zones. This propagation is thought to be the cause of the local aseismic fault slip recorded by the tiltmeters. Previously, both discrete structures and strain propagation effects were revealed in the Central Apennines and are thought also to exist in the Southern Caucasus. As in the past, the rheological properties of fault materials are revealed as viscoelastic ones. In fact, creep equations obtained by applying several viscoelastic models on our data, proved to fit quite well some of the observed tilt precursors, producing viscosity and rigidity values very similar to those reported in literature.

Key words

Fault creep ground tilt earthquake precursors 

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References

  1. Alfonsi, L., Funiciello, R., andMattei, M. (1991),Strike-slip Tectonics in the Sabine Area, Boll. Soc. Geol. It.110, 481–488.Google Scholar
  2. Bella, F., Bella, R., Biagi, P. F., Ermini, A., andSgrigna, V. (1986a),Possible Precursory Tilts Preceding Some Earthquakes (3.0≤M≤3.8) Occurred in Central Italy between February 1981 and June 1983, Earthq. Predict. Res.4, 147–154.Google Scholar
  3. Bella, F., Biagi, P. F., Ermini, A., Manjgaladze, P., andSgrigna, V. (1986b),Possible Propagation of Tilt and Strain Anomalies: Velocity and other Characteristics, Earthq. Predict. Res.4, 195–209.Google Scholar
  4. Bella, F., Bella, R., Biagi, P. F., Della Monica, G., Ermini, A., andSgrigna, V. (1987),Tilt Measurements and Seismicity in Central Italy over a Period of Approximately Three Years, Tectonophys.139, 334–338.Google Scholar
  5. Bella, F., Biagi, P. F., Della Monica, G., Ermini, A., andSgrigna, V. (1989),A Horizontal Pendulum Tiltmeter with Digital Recording System, Nuovo Cimento12C, 799–809.Google Scholar
  6. Bella, F., Biagi, P. F., Caputo, M., Della Monica, G., Ermini, A., andSgrigna, V. (1990),Very Slow-moving Crustal Strain Disturbances, Tectonophys.179, 131–139.Google Scholar
  7. Bella, F., Biagi, P. F., Caputo, M., Della Monica, G., Ermini, A., andSgrigna, V. (1993a),Ground Tilt Anomalies Accompanying the Main Earthquakes Occurred in the Central Apennines (Italy) during the Period 1986–1989, Nuovo Cimento16C, 393–406.Google Scholar
  8. Bella, F., Biagi, P. F., Caputo, M., Della Monica, G., Ermini, A., andSgrigna, V. (1993b),Ground Tilt Variations Detected in the Central Apennines (Italy) in the Period 1986–1989 and their Correlation with the Seismicity, Nuovo Cimento16C, 303–311.Google Scholar
  9. Bilham, R. G.,Delays in the onset times of near-surface strain and tilt precursors to earthquakes. InEarthquake Prediction: An International Review (eds. Simpson, P. J., and Richards, P. G.) (Geophysical Union, Washington, D.C. 1981) pp. 411–421.Google Scholar
  10. Bilham, R. G., Beavan, J., Evans, K., andHurst, K. (1985),Crustal Deformation Meteorology at Lamont-Doherty Geological Observatory, Earthq. Predict. Res.3, 391–411.Google Scholar
  11. Bonafede, M., andDragoni, M. (1982),Implication of Stress Concentration on a Strike-slip Fault in an Elastic Plate Subjected to Basal Shear Stress, Geophys. J. R. Astr. Soc.69, 369–382.Google Scholar
  12. Bonafede, M., Boschi, E., andDragoni, M. (1983),Viscoelastic Stress Relaxation on Deep Fault Sections as a Possible Source of Very Long Period Elastic Waves, J. Geophys. Res.88, 2251–2260.Google Scholar
  13. Buckley, C. P., Maloney, N. J., Wright, N. A., andKohlenberger, C. W. (1975),Variations of Crustal Tilt Patterns Preceding Southern California Earthquakes of 4.0 Magnitude or Larger (abstract), EOS Trans. AGU56, 1059.Google Scholar
  14. Caputo, M. (1967),Linear Models of Dissipation whose Q is Almost Frequency-independent, Geophys. J. R. Astr. Soc.13, 529–539.Google Scholar
  15. Caputo, M., andMainardi, F. (1971),Linear Models of Dissipation in Anelastic Solids, Riv. Nuovo Cimento1, 161–198.Google Scholar
  16. Caputo, M., Keilis-Borok, V. I., Oficerova, E., Ranzman, E. Ia., Rotwain, I., andSolovjeff, A. (1980),Pattern Recognition of Earthquake-prone Areas in Italy, Phys. Earth Planet. Inter.21, 305–320.Google Scholar
  17. Cosentino, D., andParotto, M. (1986),Assetto strutturale dei Monti Lucretili (Sabina): nuovi dati e schema tettonico preliminare, Geol. Rom.25, 73–90.Google Scholar
  18. Dobrowolsky, I. P., Zubkov, S. I., andMiachkin, V. I. (1979),Estimation of the Size of Earthquake Preparation Zones, Pure and Appl. Geophys.117, 1025–1044.Google Scholar
  19. Dragoni, M., Bonafede, M., andBoschi, E. (1982),Stress Relaxation in the Earth and Seismic Activity, Riv. Nuovo Cimento5, 1–34.Google Scholar
  20. Dragoni, M., Bonafede, M., andBoschi, E. (1984/85),On the Interpretation of Slow Ground Deformation Precursory to the 1976 Friuli Earthquake, Pure and Appl. Geophys.122, 781–792.Google Scholar
  21. Dragoni, M., Bonafede, M., andBoschi, E. (1986),Shallow Earthquakes in a Viscoelastic Shear Zone with a Depth-dependent Friction and Rheology, Geophys. J. R. Astr. Soc.86, 617–633.Google Scholar
  22. Dragoni, M.,Aseismic propagation of dislocations: A model for tilt anomalies. In Proc. 7th GNGTS National Meeting, National Research Council of Italy (ESA ed., Rome, 1988) pp. 923–934 (in Italian).Google Scholar
  23. Gabrielan, A., Sarkisin, O., andSimonian, G. (1984),Seismotectonics of the Armenia SSR, Akad. Nauk (Erevan Univ., USSR).Google Scholar
  24. Gelfand, I. M., Guberman, Sh. A., Izvekova, M. L., Keilis-Borok, V. I., Ranzman, E. Ia, (1972),Criteria of high seismicity determined by pattern recognition. InThe Upper Mantle (ed. Titsema, A. R.) Tectonophys.13, 415–422.Google Scholar
  25. Ida, Y. (1974),Slow-moving Deformation Pulses along Tectonic Faults, Phys. Earth Planet. Inter.9, 328–337.Google Scholar
  26. Jaeger, J. C., andCook, N. G. W.,Fundamentals of Rock Mechanics (Chapman and Hall, London 1979).Google Scholar
  27. Kasahara, K. (1979),Migration of Crustal Deformation, Tectonophys.52, 311–329.Google Scholar
  28. Körnig, M., andMüller, G. (1989),Rheological Models and Interpretation of Postglacial Uplift, Geophys. J. Int.,98, 243–253.Google Scholar
  29. Langbein, J. O., Burford, R. O., andSlater, L. E. (1990),Variations in Fault Slip and Strain Accumulation at Parkfield, California: Initial Results Using Two-color Geodimeter Measurements, 1984–1988, J. Geophys. Res.95, 2533–2552.Google Scholar
  30. McHugh, S., andJohnston, M. J. S.,A review of observations and dislocation modeling of some creep-related tilt perturbations from Central California. InTerrestrial and Space Techniques in Earthquake Prediction (ed. Vogel, A.) (Vieweg and Sohn, Braunschweig, Wiesbaden 1979) pp. 181–201.Google Scholar
  31. Mortensen, C. E., andJohnston, M. J. S. (1975),The Nature of Surface Tilt along 85 km of the San Andreas Fault: Preliminary Results from a 14-instrument Array, Pure and Appl. Geophys.113, 237–249.Google Scholar
  32. Parotto, M. (1980), Apennine Central, Proc. XXVI Cong. Geol. Int., Paris, 26, 33.Google Scholar
  33. Rice, J. R., andSimons, D. A. (1976),The Stabilization of Spreading Shear Faults by Coupled. Deformation-diffusion Effects in Fluid-infiltrated Porous Materials, J. Geophys. Res.81, 5322–5334.Google Scholar
  34. Salvini, F. (1993),Block Tectonics in Thin-skin Style-deformed Regions: Examples from Structural Data in the Central Apennines, Ann. Geofis.XXXVI, 97–109.Google Scholar
  35. Savage, J. C., andBurford, R. O. (1973),Geodetic Determination of Relative Plate Motion in Central California, J. Geophys. Res.78, 832–845.Google Scholar
  36. Savage, J. C., andPrescott, W. H. (1978),Asthenosphere Readjustment and the Earthquake Cycle, J. Geophys. Res.83, 3369–3376.Google Scholar
  37. Scholz, C. H. (1977),A Physical Interpretation of the Haicheng Earthquake Prediction, Nature267, 121–124.Google Scholar
  38. Spain, B., andSmith, M. G.,Functions of Mathematical Physics (Van Norstrand Reinhold Co., London 1970).Google Scholar
  39. Stuart, W., Archuleta, R. J., andLindh, A. G. (1985),Forecast Model for Moderate Earthquakes near Parkfield, California, J. Geophys. Res.90, 592–604.Google Scholar
  40. Thatcher, W. (1983),Nonlinear Strain Build-up and the Earthquake Cycle on the San Andreas Fault, J. Geophys, Res.88, 5893–5902.Google Scholar
  41. Thatcher, W., andFujita, N. (1984),Deformation of the Mikata Rhombus: Strain Buildup Following the 1923 Kanto Earthquake, Central Honshu, Japan, J. Geophys, Res.89, 2102–3106.Google Scholar
  42. Thatcher, W., andHanks, T. C. (1973),Source Parameters of Southern California Earthquakes, J. Geophys. Res.75, 8547–8576.Google Scholar
  43. Walcott, R. (1970),Flexural Rigidity, Thickness and Viscosity of the Lithosphere, J. Geophys. Res.75, 3941–3952.Google Scholar
  44. Wyss, M., andBrune, J. N. (1968),Seismic Moment, Stress, and Source Dimension for Earthquakes in the California-Nevada Region, J. Geophys. Res.73, 4681–4694.Google Scholar
  45. Zschau, J., andErgünay, O.,Turkish-German Earthquake Research Project (eds. Zschau, J., and Ergünary, O.) (Kiel Univ., Germany and Ankara Earthq. Res. Inst., Turkey 1989) pp 197–211.Google Scholar

Copyright information

© Birkhäuser Verlag 1995

Authors and Affiliations

  • F. Bella
    • 1
  • P. F. Biagi
    • 1
  • M. Caputo
    • 2
  • G. Della Monica
    • 1
  • A. Ermini
    • 1
  • P. V. Manjgaladze
    • 3
  • V. Sgrigna
    • 1
  • D. O. Zilpimiani
    • 3
  1. 1.Dipartimento di FisicaIII Università di RomaRomeItaly
  2. 2.Dipartimento di FisicaUniversità “La Sapienza”RomeItaly
  3. 3.Institute of GeophysicsGeorgian Academy of SciencesTbilisiGeorgia

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