Fault interaction and seismicity: Laboratory investigation and its seismotectonic interpretation
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Systems of two parallel linear faults of the same length with the angle of inclination α=45° were investigated under uniaxial linearly increasing load. Perspex plates were used as models. For each treated fault configuration the morphology of tensile cracks and the sequence of seismoacoustic events of shear and tensile origin were studied.
It is shown that the seismic regime of a fault system is strongly influenced by the contact conditions on a fault plane; it is different in the faults with the aseismic contact, represented by open slits, and in the faults with the seismoactive contact, represented by filled slits, respectively.
The experiments proved the dominating role of a fast shear displacement of the stick-slip type in the regime of seismic energy release of a fault system. The tensile crack generation seems to be only of little—if not negligible—importance. On the other hand, the existence of tensile cracks in a fault system can play an important role in the course of subsequent loading cycles because the stick-slip displacements can take place not only along the primary faults but also along the planes of tensile cracks.
A comparison of some results of model experiments and the already published results of geological and seismological investigations indicated that the way of seismic energy relase on faults in nature and in the laboratory could be of the same character. Several analogies between the seismic regime of a fault model and of real seismic regions were found concerning the morphology of faults, off-fault fore- and aftershocks, and earthquake doublets, respectively.
Key wordsFault interaction seismotectonic interpretation
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- Bombolakis, E. G. (1964),Photoelastic investigation of brittle crack growth within a field of uniaxial compression. Tectonophysics1, 343–351.Google Scholar
- Bombolakis, E. G. (1968),Photoelastic study of initial stages of brittle fracture in compression. Tectonophysics6, 461–473.Google Scholar
- Bombolakis, E. G. (1973),Study of the brittle fracture process under uniaxial compression. Tectonophysics18, 231–248.Google Scholar
- Brace, W. F. andBombolakis, E. G. (1963),A note on brittle crack growth in compression. J. Geophys. Res.68, 3709–3713.Google Scholar
- Corbett, E. J. andMcNally, K. C. (1978),Changes in stress indicated by ‘preshocks’ to the 1968 Borrego Mountain earthquake. EOS Trans. AGU59, 1127.Google Scholar
- Das, S. andScholz C. H. (1981),Theory of time-dependent rupture in the earth. J. Geophys. Res.,86, 6039–6051.Google Scholar
- Deng, Q. andZhang, P. (1984),Research on the geometry of shear fracture zones. J. Geophys. Res.89, 5699–5710.Google Scholar
- Hanuš, V. andVaněk, J. (1977–78),Subduction of the Cocos plate and deep active fracture zones of Mexico. Geofisica International17, 14–53.Google Scholar
- Hanus, V. andVaněk, J. (1984),Earthquake distribution and volcanism in Kamchatka, Kurile Islands and Hokkaido. Studia Geoph. et Geod.28, 36–55, 129–148, 248–271.Google Scholar
- Hoek, E. andBieniawski, Z. T. (1965),Brittle fracture propagation in rock under compression. Int. J. Frac. Mech.1, 137–155.Google Scholar
- Kozák, J., Lokajíček, T., Šílený, J., Špičák, A. andWaniek, L. (1985),Elementary mechanisms of seismic energy release on single fault. Int. Symp.Physics of Fracturing and Seismic Energy Release, Liblice, Czechoslovakia, October 1985, Abstract No. 25.Google Scholar
- Kranz, R. L. (1979),Crack-crack and crack-pore interactions in stressed granite. Int. J. Rock Mech. Mining Sci.16, 37–47.Google Scholar
- Lay, T. andKanamori, H. (1980),Earthquake doublets in Solomon Islands. Phys. Earth Planet. Int.21, 283–304.Google Scholar
- Niewiadomski, J. andRitsema, A. R. (1980),The stress field induced by cracks and the occurrence of earthquakes. Geophysics B83, 361–377.Google Scholar
- Niewiadomski, J. andRybicki, K. (1984),The stress field induced by antiplane shear cracks—application to earthquake study. Bull. Earthq. Res. Inst. Tokyo Univ.59, 67–81.Google Scholar
- Sanders, C. O. andKanamori, H. (1984),A seismotectonic analysis of the Anza seismic gap, San Jacinto fault zone, Southern California. J. Geophys. Res.89, 5873–5890.Google Scholar
- Segall P. andPollard, D. D. (1980),Mechanics of discontinuous faults, J. Geophys. Res.85, 4337–4350.Google Scholar
- Špičák, A. (1985),Mechanismus zemětřesení a tektonická stavba (Earthquake mechanism and tectonic structure). in Czech, Ph.D. Thesis, Geophys. Inst. Czech. Acad. Sci. (Prague 1985, not published).Google Scholar
- Špičák, A. andLokajíček, T. (1985),Generation and morphology of tensile cracks in a system of parallel faults: results of model experiments. Acta Montana ÚGG ČSAV71, 49–62.Google Scholar
- Špičák, A., Lokajíček, T., andWaniek L. (1986),Seismic regime of a single fault model. Pure Appl. Geophys. 124, 4/5, 793–810.Google Scholar