Abstract
More than a thousand acoustic-emission (AE) hypocenters were determined in a cylindrical andesite specimen under two-stage uniaxial creep at stresses of 204 and 214 MPa. Strains were monitored for 6 peripheral points at the middle part of the cylindrical specimen's wall. The strain data indicate gradual increase of nonuniform deformation during steady creep and strong intensification of the nonuniformity during acceleration creep and, therefore, biased stress distribution within the specimen. The correlation between dilatant strain and AE hypocenters was investigated for whether or not tensile cracks emit AE. The region with high AE activity shows only a small dilatant strain. This negative correlation between AE and the dilatant region may eliminate tensile cracks as possible AE sources. A composite focal-mechanism solution of local AE events, covering a wide solid angle of the focal hemisphere, indicates that shear fractures emit AE waves. The direction of the compressional axis in this solution shows a significant deviation from that inferred from the applied external force, suggesting that the local stress field is governed by preexisting weak zones that are, presumably, produced by tensile cracks within the specimen. AE hypocenters tended to form clusters during steady creep under the constant compressional stress. During acceleration creep caused by a small step increase of the external stress, the preceding clusters disappeared while a new cluster appeared in an incipient fault plane. This suggests that changes in seismicity pattern such as migrations or quiescences of swarm—important clues for earthquake predictions—may be caused by an instantaneous change in the tectonic-stress levels.
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References
Brace, W. F., andOrange, A. S. (1968),Further studies of the effects of pressure on electrical resistivity of rocks. J. Geophys. Res.73, 5407–5420.
Brace, W. F., Paulding, B. W., andScholz, C. (1966),Dilatancy in the fracture of crystalline rocks, J. Geophys. Res.71, 3939–3953.
Byerlee, J. D., andLockner, D. (1977),Acoustic emission during fluid injection into rock. InProceedings of the First Conference of Acoustic Emission/Microseismic Activity in Geologic Structure and Materials, pp. 87–98, Trans Tech Publications, Clauthal, Germany.
Gupta, N. I. (1973),Seismic velocities in rock subjected to axial loading up to shear fracture, J. Geophys. Res.78, 6667–6674.
Ishida, M., andKanamori, H. (1978),The foreshock activity of the 1971 San Fernando Earthquake, Bull. Seism. Soc. Am.68, 1265–1297.
Kranz, R. L. (1979),Crack growth and development during creep of Barre granite, Int. J. Rock Mech. Mining Sci.16, 37–47.
Kurita, K., Swanson, P. L., Getting, I. C., andSpetzler, H. (1983),Surface deformation of Westerly granite during creep, Geophys. Res. Lett.10, 75–78.
Kusunose, K., Nishizawa, O., Ito, H., Ishido, T., andHasegawa, I. (1981),Source mechanism of acoustic emission in rocks under uniaxial compression (in Japanese), Zisin, J. Seism. Soc. Japan34, 241–250.
Kusunose, K., Nishizawa, O., andOnai, K. (1982),AE gap in a rock under uniaxial compression (in Japanese), Zisin, J. Seism. Soc. Japan35, 91–102.
Lockner, D., andByerlee, J. (1977),Acoustic emission and fault formation in rocks. InProceedings of the First Conference on Acoustic Emission/Microseismic Activity in Geologic Structures and Materials (R. Hardy, Jr., and F. W. Leighton, Eds.), pp. 99–107, Trans Tech Publications, Clauthal, Germany.
Lockner, D., andByerlee, J. (1980),Development of fracture planes during creep in granite. InProceedings of the Second Conference on Acoustic Emission/Microseismic Activity in Geologic Structures and Materials (H. R. Hardy, Jr., and F. W. Leighton, Eds.), pp. 11–25, Trans Tech Publications, Clauthal, Germany.
Lockner, D. A., Walsh, J. B., andByerlee, J. D. (1977),Change in seismic velocity and attenuat during deformation of granite, J. Geophys. Res.82, 5347–5378.
Matsushima, S. (1960a),Variation of the elastic wave velocities of rocks in the process of deformation and fracture under high pressure, Disaster Prevention Res. Inst. Kyoto Univ. Bull.32, 1–8.
Matsushima, S. (1960b),On the flow and fracture of igneous rocks, Disaster Prevention Res. Inst. Kyoto Univ. Bull.36, 1–9.
McKenzie, D. P. (1969),The relation between fault plane solutions for earthquakes and the directions of the principal stress, Bull. Seism. Soc. Am.59, 591–601.
Mogi, K. (1962),Study of elastic shocks caused by the heterogeneous materials and its relation to earthquake phenomena, Bull. Earthq. Res. Inst. Tokyo Univ.40, 125–173.
Mogi, K. (1968a),Sequential occurrence of recent great earthquakes, J. Phys. Earth16, 30–36.
Mogi, K. (1968b),Source locations of elastic shocks in the fracturing process in rocks (1), Bull. Earthq. Res. Inst. Tokyo Univ.46, 1103–1125.
Mogi, K. (1979),Two kinds of seismic gap, Pageoph117, 1172–1186.
Nakamura, K. (1979),\(\sigma _{H_{max} }\) trajectories east of Suruga Trough, Japan—An effect of flexure of lithospheric plate (in Japanese), Zisin, J. Seism. Soc. Japan32, 370–372.
Nishizawa, O., Kusunose, K., andOnai, K. (1981),A study of space-time distribution of AE hypocenters in a rock sample under uniaxial compression (in Japanese), Bull. Geol. Surv. Japan32, 473–486.
Nishizawa, O., Kusunose, K., Yanagidani, T., Oguchi, F., andEhara, S. (1982),Stochastic process of the occurrence of AE events and hypocenter distributions during creep in Ohshima granite (in Japanese), Zisin, J. Seism. Soc. Japan35, 117–132.
Nur, A., andSimmons, G. (1969),Stress-induced velocity anisotropy in rock: An experimental study, J. Geophys. Res.74, 6667–6674.
Ohnaka, M., andMogi, K. (1982),Frequency characteristics of acoustic emission in rocks under uniaxial compression and its relation to the fracturing process to failure, J. Geophys. Res.87, 3873–3884.
Ohtake, M., Matsumoto, T., andLatham, G. V. (1977),Seismicity gap near Oxaca, Southern Mexico, as a probable precursor to a large earthquake, Pure appl. Geophys.115, 375–285.
Robertson, E. C. (1960),Creep in Solenhofen limestone, Geol. Soc. Am. Mem.79, 227–244.
Sano, O., Ito, I., andTerada, M. (1981),Influence of strain rate on dilatancy and strength of Oshima granite under uniaxial compression, J. Geophys. Res.86, 9299–9311.
Sano, O., Terada, M., andEhara, S. (1982),A study on the time-dependent microfracturing and strength of Oshima granite, Tectonophysics84, 343–362.
Sato, T. (1973),A note on body wave radiation from expanding tensile crack, Sci. Rep. Tohoku Univ. Geophysics25, 415–431.
Scholz, C. H. (1968a),Microfracturing and the inelastic deformation of rock in compression, J. Geophys. Res.73, 1417–1432.
Scholz, C. H. (1968b),Experimental study of fracturing process in brittle rock, J. Geophys. Res.73, 1447–1454.
Scholz, C. H. (1968c),Mechanism of creep in brittle rock, J. Geophys. Res.73, 3295–3302.
Scholz, C. H. (1968d),The frequency-magnitude relation of micro-fracturing in rock and its relation to earthquakes, Bull. Seism. Soc. Am.58, 399–415.
Seno, T. (1980),Tectonics in Izu peninsula (in Japanese), Earth Monthly,2, 81–86.
Shimizu, N., andMaeda, I. (1982),The effect of velocity anisotropy on AE source locations in a very large granite sample, J. Fac. Sci. Hokkaido Univ., Ser. VII (Geophysics)7, 135–141.
Soga, N., Mizutani, H., Spetzler, H., andMartin, R. J., III (1978),The effect of dilatancy on velocity anisotropy in Westerly granite, J. Geophys. Res.83, 4451–4458.
Sondergeld, C. H., andEstey, L. H. (1981)Acoustic emission study during the cyclic loading of Westerly granite, J. Geophys. Res.86, 2915–2924.
Sondergeld, C. H., andEstey, L. H. (1981),Source mechanism and microfracturing during uniaxial cycling of rock, Pure appl. Geophys.120, 151–166.
Takayanagi, A., Yamakawa, N., andTanaka, M. (1976),Earthquakes and tectonics in the southern part of Izu peninsular (in Japanese). InProgram and Abstr. Seism. Soc. Japan, 1977 No. 2, p. 66.
Tapponier, R., andBrace, W. F. (1976),Development of stress-induced microcracks in Westerly granite, Int. J. Rock Mech. Sci. Geomech. Abstr.13, 103–112.
Tocher, D. (1957),Anisotropy in rocks under simple compression, Trans. Amer. Geophys. Union35, 89–94.
Tsukahara, H., Ikeda, R., Satake, H., andTakahashi, H. (1980),Stress measurements by hydrofracturing at Nishiizu Town, Shizuoka Prefecture (in Japanese), Zisin, J. Seism. Soc. Japan33, 317–327.
Yamakawa, N. (1971),Stress field in focal regions, J. Phys. Earth19, 347–355.
Yamashina, K., andInoue, Y. (1979),A doughnut-shaped pattern of seismic activity preceding the Shimane earthquakes of 1978, Nature278, 48–50.
Yanagidani, T., Fukushima, K., Ehara, S., Nishizawa, O., andKusunose, K. (1982),On AE in rock under creep (in Japanese). InProgram and Abstr. Seism. Soc. Japan, 1981 No. 1, B58–B59, 1982.
Zoback, M., andZoback, M. (1980),State of stress in the conterminous United States, J. Geophys. Res.85, 6113–6156.
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Nishizawa, O., Onai, K. & Kusunose, K. Hypocenter distribution and focal mechanism of AE events during two stress stage creep in Yugawara andesite. PAGEOPH 122, 36–52 (1984). https://doi.org/10.1007/BF00879648
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DOI: https://doi.org/10.1007/BF00879648