Abstract
Earthquakes are caused by the failure of faults, driven by tectonic stress build-up in the Earth’s crust. To study the earthquake preparation process and assess regional earthquake potentials, it is vitally important to understand the crustal stress evolution process and identify its change in pattern associated with the seismogenic process. In this study we investigate the focal mechanism orientations of earthquakes in southern California from 1982 to 1999, basing on a focal mechanism catalog from Hauksson. We find that for the two large earthquakes occurred in southern California, the 1992 MW7.3 Landers and the 1999 MW7.1 Hector Mine, the orientations of focal mechanisms near the coming earthquake tend to converge to the stress direction promoting the rupture of the coming earthquake and align with its focal mechanism about half-year before its occurrence, suggesting that the tectonic stress field gets more organized in favor of the rupture of the event pre-seismically. The degree of stress convergence is measured by the orientation angle RMS (root mean square) between the preshocks’ focal mechanisms and the focal mechanism of the large event studied, and its time series recorded the stress convergence process. The degree of anomalies, measured by the F-tests, indicates that the convergence of stress orientations become significant at 90% confidence about half-year prior to both the Landers and Hector Mine quakes, and it becomes even more prominent at 99% confidence right before the occurrences. Our study may be of significance for assessment of regional seismic potentials.
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References
Aki K and Richards P (2002). Quantitative Seismology. 2nd edition. University Science Books, Sausalito, California, 700 pp.
Bird P and Kagan Y Y (2004). Plate-tectonic analysis of shallow seismicity: apparent boundary width, beta, corner magnitude, coupled lithosphere thickness, and coupling in seven tectonic settings. Bull Seism Soc Amer94(6): 2 380–2 399.
Bowman D D and King G C P (2001). Accelerating seismicity and stress accumulation before large earthquake. Geophys Res Lett28(21): 4 039–4 042.
Chen Y (1978). Consistence of focal mechanism as a new parameter in describing seismic activity. Chinese J Geophys19(2): 142–159 (in Chinese).
Crampin S, Volti T and Stefánsson R (1999). A successfully stress-forecast earthquake. Geophys J Int138: F1–F5.
Crampin S, Volti T and Stefánsson R (2004). Response to “A statistical evaluation of a ’stress-forecast’ earthquake” by T. Seher &I. G. Main. Geophys J Int157: 194–199.
Diao G L and Yu X C (1980). Synthesis fault plane solution before and after Tangshan earthquake in Beijing-Tianjin-Tangshan-Zhangjiakou region. Northwestern Seismological Journal2(3): 39–47 (in Chinese with English abstract).
Diao G L, Yu L M and Li Q Z (1994). Variation of stress field in the source region around a strong shock: an example. Acta Seismologica Sinica7(1): 85–92.
Frohlich C and Davis S D (1999). How well constrained are well-constrained T, B, and P axes in moment tensor catalogs? J Geophys Res104: 4 901–4 910.
Geller R J (1996). Debate on evaluation of the VAN method: Editor’s introduction. Geophys Res Lett23(11): 1 291–1 293.
Geller R J (1997). Earthquake prediction: A critical review. Geophys J Int131: 425–450.
Geller R J, Jackson D D, Kagan Y Y and Mulargia F (1997). Earthquake cannot be predicted. Science275: 1 616–1 617.
Gephart J W (1990). FMSI: A FORTRAN program for inverting fault/slikenside and earthquake focal mechanism data to obtain the regional stress tensor. Computers and Geosciences16: 953–989.
Gephart J W and Forsyth D W (1984). An improved method for determining the regional stress tensor using earthquake focal mechanism data: application to the San Fernando earthquake sequence. J Geophys Res89: 9 305–9 320.
Hardebeck J L and Michael A J (2006). Damped regional-scale stress inversions: Methodology and examples for southern California and the Coalinga aftershock sequence. J Geophys Res111: B11310, doi:10.1029/2005JB004144.
Hauksson E (2000). Crustal structure and seismicity distribution adjacent to the Pacific and North America plate boundary in southern California. J Geophys Res105: 13 875–13 903.
Kagan Y Y (1991). 3-D rotation of double-couple earthquake sources. Geophys J Int106(3): 709–716.
Kagan Y Y (2003). Accuracy of modern global earthquake catalogs. Phys Earth Planet Inter135(2–3): 173–209.
Kagan Y Y (2007). Simplified algorithms for calculating double-couple rotation. Geophys J Int171(1): 411–418, doi:10.1111/j.1365-246X.2007.03538.x.
Kagan Y Y and Jackson D D (2000). Probabilistic forecasting of earthquakes. Geophys J Int143(2): 438–453.
Kagan Y Y, Jackson D D and Rong Y F (2006). A new catalog of southern California earthquakes, 1800–2005. Seism Res Lett77(1): 30–38.
Michael A J (1987). Use of focal mechanisms to determine stress: a control study. J Geophys Res92: 357–368.
Okal E A (2005). A re-evaluation of the great Aleutian and Chilean earthquakes of 1906 August 17. Geophys J Int161(2): 268–282.
Pondrelli S, Salimbeni S, Ekstroem G, Morelli A, Gasperini P and Vannucci G (2006). The Italian CMT dataset from 1977 to the present. Phys Earth Planet Inter159: 286–303.
Qian F Y, Zhao Y L, Yu M M, Wang Z X, Liu X W and Chang S M (1982). Abnormal variation of georesistivity before earthquakes. Sciencia Sinica (Series B) 9: 831–839 (in Chinese).
Seher T and Main I G (2004). A statistical evaluation of a ’stress-forecast’ earthquake. Geophys J Int157: 187–193.
Smith S W and Sammis C G (2004). Revisiting the tidal activation of seismicity with a damage mechanics and friction point of view. Pure Appl Geophys161: 2 393–2 404.
Trotta J E and Tullis T E (2006). An independent assessment of the Load/Unload Response Ratio (LURR) proposed method of earthquake prediction. Pure Appl Geophys163: 2 375–2 387.
Wang J G and Diao G L (2005). Consistent CMT solutions from Harvard University before great earthquakes in Kuril Islands and its significance for earthquake prediction. Acta Seismologica Sinica18(2): 189–195.
Yin X, Chen X, Song Z and Yin C (1995). A new approach to earthquake prediction: The load/unload response ratio (LURR) theory. Pure Appl Geophys145(3/4): 703–715.
Yin X, Wang Y, Peng K, Bai Y L, Wang H T and Yin X F (2000). Development of a new approach to earthquake prediction: Load/unload response ratio (LURR) theory. Pure Appl Geophys157: 2 365–2 383.
Yin X C and Yin C (1991). The precursor of instability for nonlinear system and its application to earthquake prediction. Science in China (Series B) 34: 977–986.
Yu H, Shen Z, Wan Y, Zhu Q and Yin X (2006). Increasing critical sensitivity of the Load/Unload Response Ratio before large earthquakes with identified stress accumulation pattern. Tectonophysics428: 87–94, doi:10.1016/j.tecto.2006.09.006.
Zhao Y L, Lu J, Li Z N, Qian F Y and Zhang H K (1996). Strain-geoelectric resistivity precursor and the virtual dislocation model to the Tangshan earthquake. Acta Seismologica Sinica9(1): 103–108.
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Wan, Y., Sheng, S. Seismological evidence for the convergence of crustal stress orientation before large earthquakes. Earthq Sci 22, 623–629 (2009). https://doi.org/10.1007/s11589-009-0623-z
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DOI: https://doi.org/10.1007/s11589-009-0623-z