Earthquakes on dipping faults: The effects of broken symmetry

Science

Volumn 280, Issue 5366, 1998, Pages 1055-1059

  Oglesby, David D ^a   Archuleta, Ralph J ^a   Nielsen, Stefan B ^a  

^a UNIVERSITY OF CALIFORNIA   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EARTHQUAKE; FAULT GEOMETRY; GROND MOTION; SEISMICITY; STRESS;

ARTICLE; EARTHQUAKE; GEOLOGY; GEOMETRY; MATHEMATICAL COMPUTING; MOTION; PRIORITY JOURNAL; SHEAR STRESS; TENSILE STRENGTH; UNITED STATES;

EID: 0032524382     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.280.5366.1055     Document Type: Article

References (40)

1. A recent example of an earthquake in a compressional regime is the 1994 Northridge earthquake, which was modeled by D. Wald et al. [Bull. Seismol. Soc. Am. 86, S49 (1996)]. One earthquake in an extensional regime is the 1983 Borah Peak, Idaho, earthquake, which is described by W. D. Richins et al. [ibid. 77, 694 (1987)].
2. A recent example of an earthquake in a compressional regime is the 1994 Northridge earthquake, which was modeled by D. Wald et al. [Bull. Seismol. Soc. Am. 86, S49 (1996)]. One earthquake in an extensional regime is the 1983 Borah Peak, Idaho, earthquake, which is described by W. D. Richins et al. [ibid. 77, 694 (1987)].
3. A normal fault is one in which the hanging wall moves down and outward with respect to the foot wall. A thrust or reverse fault is one in which the hanging wall moves up and inward with respect to the foot wall. A thrust fault has a dip angle <45° with respect to the free surface, and a reverse fault has a dip angle >45°. For simplicity, however, we will refer to all thrust and reverse earthquakes as thrust. The hanging wall of a dipping fault is defined as the block on top of the fault, which includes the acute angle with the free surface (Fig. 1). The footwall is the block below the fault, which includes the obtuse angle with the free surface.
4. N. Abrahamson and P. Somerville, Bull. Seismol. Soc. Am. 86, S93 (1996).
5. K. Steinbrugge et al., in San Fernando, California, Earthquake of 9 February 1971, G. Oakeshott, Ed. [Calif. Div. Mines Geol. Bull. 196, 323 (1975)] .
6. K. Steinbrugge et al., in San Fernando, California, Earthquake of 9 February 1971, G. Oakeshott, Ed. [Calif. Div. Mines Geol. Bull. 196, 323 (1975)] .
7. R. Nason, in San Fernando, California, Earthquake of February 9, 1971, L. Murphy, Ed. (U.S. Department of Commerce-NOAA, Washington, DC, 1973), vol. 3, p. 123.
8. P. Jungels and G. Frazier, J. Geophys. Res. 78, 5062 (1973); T. Heaton, Phys. Earth Planet. Int. 64, 1 (1990).
9. P. Jungels and G. Frazier, J. Geophys. Res. 78, 5062 (1973); T. Heaton, Phys. Earth Planet. Int. 64, 1 (1990).
10. J. Brune, Proc. Indian Acad. Sci. (Earth Planet. Sci.) 105, L197 (1996).
11. A. McGarr, J. Geophys. Res. 89, 6969 (1984); N. Abrahamson and K. Shedlock, Seismol. Rev. Lett. 68, 9 (1997).
12. A. McGarr, J. Geophys. Res. 89, 6969 (1984); N. Abrahamson and K. Shedlock, Seismol. Rev. Lett. 68, 9 (1997).
13. R. Whirley et al., DYNA2D: A Nonlinear, Explicit, Two-Dimensional Finite Element Code for Solid Mechanics - User Manual (UCRL-MA-110630, University of California, Lawrence Livermore National Laboratory, Livermore, CA, 1992).
14. D. Andrews, J. Geophys. Res. 81, 3575 (1976); ibid., p. 5679; R. Archuleta, thesis, University of California, San Diego (1976); _ and P. Frazier, Bull. Seismol. Soc. Am. 68, 541 (1978); S. Day, ibid. 72, 705 (1982); ibid., p. 1881; A. Ruina, J. Geophys. Res. 88, 10359 (1983); T. Mikumo and T. Miyatake, Geophys. J. Int. 112, 481 (1993); R. Madariaga and A. Cochard, Proc. Natl. Acad. Sci. U.S.A. 93, 3819 (1996).
15. D. Andrews, J. Geophys. Res. 81, 3575 (1976); ibid., p. 5679; R. Archuleta, thesis, University of California, San Diego (1976); _ and P. Frazier, Bull. Seismol. Soc. Am. 68, 541 (1978); S. Day, ibid. 72, 705 (1982); ibid., p. 1881; A. Ruina, J. Geophys. Res. 88, 10359 (1983); T. Mikumo and T. Miyatake, Geophys. J. Int. 112, 481 (1993); R. Madariaga and A. Cochard, Proc. Natl. Acad. Sci. U.S.A. 93, 3819 (1996).
16. D. Andrews, J. Geophys. Res. 81, 3575 (1976); ibid., p. 5679; R. Archuleta, thesis, University of California, San Diego (1976); _ and P. Frazier, Bull. Seismol. Soc. Am. 68, 541 (1978); S. Day, ibid. 72, 705 (1982); ibid., p. 1881; A. Ruina, J. Geophys. Res. 88, 10359 (1983); T. Mikumo and T. Miyatake, Geophys. J. Int. 112, 481 (1993); R. Madariaga and A. Cochard, Proc. Natl. Acad. Sci. U.S.A. 93, 3819 (1996).
17. D. Andrews, J. Geophys. Res. 81, 3575 (1976); ibid., p. 5679; R. Archuleta, thesis, University of California, San Diego (1976); _ and P. Frazier, Bull. Seismol. Soc. Am. 68, 541 (1978); S. Day, ibid. 72, 705 (1982); ibid., p. 1881; A. Ruina, J. Geophys. Res. 88, 10359 (1983); T. Mikumo and T. Miyatake, Geophys. J. Int. 112, 481 (1993); R. Madariaga and A. Cochard, Proc. Natl. Acad. Sci. U.S.A. 93, 3819 (1996).
18. D. Andrews, J. Geophys. Res. 81, 3575 (1976); ibid., p. 5679; R. Archuleta, thesis, University of California, San Diego (1976); _ and P. Frazier, Bull. Seismol. Soc. Am. 68, 541 (1978); S. Day, ibid. 72, 705 (1982); ibid., p. 1881; A. Ruina, J. Geophys. Res. 88, 10359 (1983); T. Mikumo and T. Miyatake, Geophys. J. Int. 112, 481 (1993); R. Madariaga and A. Cochard, Proc. Natl. Acad. Sci. U.S.A. 93, 3819 (1996).
19. D. Andrews, J. Geophys. Res. 81, 3575 (1976); ibid., p. 5679; R. Archuleta, thesis, University of California, San Diego (1976); _ and P. Frazier, Bull. Seismol. Soc. Am. 68, 541 (1978); S. Day, ibid. 72, 705 (1982); ibid., p. 1881; A. Ruina, J. Geophys. Res. 88, 10359 (1983); T. Mikumo and T. Miyatake, Geophys. J. Int. 112, 481 (1993); R. Madariaga and A. Cochard, Proc. Natl. Acad. Sci. U.S.A. 93, 3819 (1996).
20. D. Andrews, J. Geophys. Res. 81, 3575 (1976); ibid., p. 5679; R. Archuleta, thesis, University of California, San Diego (1976); _ and P. Frazier, Bull. Seismol. Soc. Am. 68, 541 (1978); S. Day, ibid. 72, 705 (1982); ibid., p. 1881; A. Ruina, J. Geophys. Res. 88, 10359 (1983); T. Mikumo and T. Miyatake, Geophys. J. Int. 112, 481 (1993); R. Madariaga and A. Cochard, Proc. Natl. Acad. Sci. U.S.A. 93, 3819 (1996).
21. D. Andrews, J. Geophys. Res. 81, 3575 (1976); ibid., p. 5679; R. Archuleta, thesis, University of California, San Diego (1976); _ and P. Frazier, Bull. Seismol. Soc. Am. 68, 541 (1978); S. Day, ibid. 72, 705 (1982); ibid., p. 1881; A. Ruina, J. Geophys. Res. 88, 10359 (1983); T. Mikumo and T. Miyatake, Geophys. J. Int. 112, 481 (1993); R. Madariaga and A. Cochard, Proc. Natl. Acad. Sci. U.S.A. 93, 3819 (1996).
22. D. Andrews, J. Geophys. Res. 81, 3575 (1976); ibid., p. 5679; R. Archuleta, thesis, University of California, San Diego (1976); _ and P. Frazier, Bull. Seismol. Soc. Am. 68, 541 (1978); S. Day, ibid. 72, 705 (1982); ibid., p. 1881; A. Ruina, J. Geophys. Res. 88, 10359 (1983); T. Mikumo and T. Miyatake, Geophys. J. Int. 112, 481 (1993); R. Madariaga and A. Cochard, Proc. Natl. Acad. Sci. U.S.A. 93, 3819 (1996).
23. n, where μ′ is the sliding frictional coefficient.
24. The stress drop is a cosine function from with a drop time of 0.2 s. This form corresponds to a slip-weakening friction law, with an effective slip-weakening distance (15) of 1 to 20 cm, depending on the slip rate.
25. We derive a general solution for the change in rupture criterion in a manner analogous to that of S. Nielsen [Geophys. Rev. Lett. 25, 125 (1998)].
26. The stress field in the vicinity of a slip-weakening crack has been explored [Y. Ida, J. Geophys. Res. 77, 3796 (1972); D. Andrews, ibid. 81, 5679 (1976)].
27. The stress field in the vicinity of a slip-weakening crack has been explored [Y. Ida, J. Geophys. Res. 77, 3796 (1972); D. Andrews, ibid. 81, 5679 (1976)].
28. J. Rudniki and M. Wu, ibid. 100, 22173 (1995).
29. Breakout phases (large radiation pulses emitted when the rupture front breaks through the free surface) are examined in R. Burridge and G. Halliday, Geophys. J. R. Astron. Soc. 25, 261 (1971).
30. B. J. Shi et al., in preparation.
31. P. Davis and L. Knopoff, Geophys. J. Int. 106, 581 (1991).
32. This may be an indication that our friction law or healing criterion, or both, may not be valid right at the free surface.
33. 0 = μs̄A, where μ is the shear modulus, s̄ is the average slip on the fault, and A is the area on the fault in which slip occurred.
34. Examples of aftershock locations are seen in the 1983 Coalinga, California, earthquake; the 1981 Corinth, Greece, earthquake; the 1980 El Asnam, Algeria, earthquake; the 1982 Miramichi, Canada, earthquake [D. Eberhart-Phillips and P. Reasenberg, in The Coalinga, California, Earthquake of May 2, 1983, M. Rymer and W. Ellsworth, Eds., U.S. Geol. Surv. Prof. Pap. 1487, 171 (1990)]; and the 1994 Northridge earthquake [H. Thio and H. Kanamori, Bull Seismol. Soc. Am. 86, S84 (1996)].
35. Examples of aftershock locations are seen in the 1983 Coalinga, California, earthquake; the 1981 Corinth, Greece, earthquake; the 1980 El Asnam, Algeria, earthquake; the 1982 Miramichi, Canada, earthquake [D. Eberhart-Phillips and P. Reasenberg, in The Coalinga, California, Earthquake of May 2, 1983, M. Rymer and W. Ellsworth, Eds., U.S. Geol. Surv. Prof. Pap. 1487, 171 (1990)]; and the 1994 Northridge earthquake [H. Thio and H. Kanamori, Bull Seismol. Soc. Am. 86, S84 (1996)].
36. Y. Zeng, personal communication; R. Sibson, personal communication.
37. Y. Zeng, personal communication; R. Sibson, personal communication.
38. Fault friction and weakness are discussed in detail in C. Scholz, The Mechanics of Earthquakes and Faulting (Cambridge Univ. Press, Cambridge, 1989), pp. 44-91.
39. J. Byerlee, Pure Appl. Geophys. 116, 615 (1978).
40. Computations for this study were carried out primarily on the SGI Origin 2000 at the Materials Research Laboratory, University of California, Santa Barbara (UCSB) (NSF grant CDA96-01954). This research was supported by UCSB, UCSB/Campus Laboratory Collaboration grant 08950868, and Lawrence Livermore National Laboratory-Institute of Geophysics and Planetary Physics grant 98-GS012. S.B.N. was supported by the Materials Research Science and Engineering Center Program of the NSF under award DMR96-32716. This work is Institute for Crustal Studies contribution 0286-69EQ. The authors gratefully acknowledge the extensive programming advice of E. Zywicz and the support and advice of W. Foxall and L. Hutchings.