Two models for earthquake forerunners

Geofisica pura e applicata - Tập 113 - Trang 169-181 - 1975
V. I. Mjachkin1, W. F. Brace2, G. A. Sobolev1, J. H. Dieterich3
1Institute of Earth Physics, Moscow, USSR
2MIT Earth Sciences Department, Cambridge
3US Geological Survey, Menlo Park

Tóm tắt

Similar precursory phenomena have been observed before earthquakes in the United States, the Soviet Union, Japan, and China. Two quite different physical models are used to explain these phenomena. According to a model developed by US seismologists, the so-called dilatancy diffusion model, the earthquake occurs near maximum stress, following a period of dilatant crack expansion. Diffusion of water in and out of the dilatant volume is required to explain the recovery of seismic velocity before the earthquake. According to a model developed by Soviet scientists growth of cracks is also involved but diffusion of water in and out of the focal region is not required. With this model, the earthquake is assumed to occur during a period of falling stress and recovery of velocity here is due to crack closure as stress relaxes. In general, the dilatancy diffusion model gives a peaked precursor form, whereas the dry model gives a bay form, in which recovery is well under way before the earthquake. A number of field observations should help to distinguish between the two models: study of post-earthquake recovery, time variation of stress and pore pressure in the focal region, the occurrence of pre-existing faults, and any changes in direction of precursory phenomena during the anomalous period.

Tài liệu tham khảo

I. L. Nersesov, A. N. Semionov andI. G. Simbireva,Space time distribution of ratios of travel times of transverse and longitudinal waves in Garm region, Exp. Seismology (1971), Sbornik, 334. O. M. Barsukov,Relationship between the electrical resistivity of rocks and tectonic processes, Izv. Earth Physics No. 1 (1970), 84. V. I. Ulomov andB. Z. Malashev,O predvestike silnogo tecktonicheskogo zemletria senia, Doke. A.N. SSSR,176 No. 2 (1967). Y. P. Aggarwal, L. R. Sykes, J. Armbruster andM. L. Sbar,Premonitory changes in seismic velocity and earthquake prediction, Nature241 (1973), 101. J. H. Whitcomb, J. D. Garmany andD. L. Anderson,Earthquake prediction: Variation of seismic velocities before the San Fernando earthquake, Science180 (1973), 632. R. Robinson, R. L. Wesson andW. L. Ellsworth,Variation of P-wave velocity before the Bear Valley, California, earthquake of 24 February 1972, Science184 (1974), 1281. H. A. Sadovsky,Otvetstennij redactor. Sbornik. Physica ochaga zemletriasenia, Nauka, Moscow (in press). V. I. Mjachkin, G. A. Sobolev, N. A. Dolbilkina, V. N. Morosov andV. B. Preobrazensky,The study of variations in geophysical fields near focal zones of Kamchatka, Tectonophysics14 (1972), 287. W. F. Brace andE. G. Bombolakis,A note on brittle crack growth in compression, J. Geophys. Res.68 (1963), 3709. B. V. Kostrov,Teoria Ochaga zemletriasenia Nauka, Moscow (in press). V. M. Finkel,Physica razruschenia, Mettalurgia, Moscow (1970). K. Mogi,Source locations of elastic shocks in the fracturing process in rocks, Bull. Seism. Soc. Japan46 (1968), 5. M. V. Raz andS. N. Chernischov,Treschinovatost i svoistra treschinovatosty gornick porod, Nedra, Moscow (1970). G. A. Sobolev,The study of precursors of the failure under biaxial compression, this issue Pure and Appl. Geophys. (in press). V. I. Keilis-Borok andL. N. Molinovskaja,Ob odnoi zakonomernosty v vozniknovenii selnikh zemletriasenii. Sbornik Seismikheskie metody issledovania, Nauka, Moscow (1966). S. A. Fedotov,O seismicheskom ziele, vozmozhnosty kolichestvenogo seismicheskogo raionirovania i dolgosrochnom seismikhiskom prognoze. Seismicheskie raionirovanie SSSR, Nauka, Moscow (1968). U. A. Mamadaliev,Ob issledovanii parametrov seismicheskogo regima vo vremeny i prostranstve Voprosy regionalnoi seismichnosty Szednei Azii Ilim, Phrunze (1962). A. N. Semionov,Izmenenie otnoschenia vremioi probega poperechnich i prodolnich voln pered silnimy zemletriaseniamji, Izvestia AN SSSR, Physika Zemly, No. 4 (1969). V. I. Mjachkin andN. A. Dolbilkina,Seismicheskoe prosvechivanie ochagorikh zon, VINITI, Moscow (1973). M. S. Anziferov,O primenenii geoakusticheskide metodov k rescheniu problemy prognoza zemletziasenij, Trudy Geophysicheskogo Instituta, No. 25 (1954). I. Tsubokava, V. Ogava andT. Hayashi,Crustal movements before and after the Niigata earthquake, J. Geol. Soc. Japan10 (1964). L. A. Latinina andR. M. Karmaleeva,Izmerenie medlennikh dvizhenii v zemnoi core kak metod poiska predvestnikov zemletziosenii, Sbornik. Physicheskie osnovania poiskov metodov prognoza zemletriasenii, Nauka, Moscow (1970). A. E. Ostrovskii,Ob izmeneniakh naklonov zemnoi poverkhnosty pered silnimji blizkimi zemletriaseniami. Sbornik. Physicheskie osnovania poiskov metodov prognoza zemletriasenii, Nauke, Moscow (1970). G. A. Sobolev andV. N. Morosov,Localnie vozmuschenia electricheskogo polja na kamchatke i ikh sviazi s zemletriaseniamy. Sbornik. Physicheskie osnovania poiskov metodov prognoza zemletriasenii, Nauka, Moscow (1970). P. Bridgman,Volume changes in the plastic stages of simple compression, J. Appl. Phys.20 (1949), 1241. B. W. Paulding, Jr., Crack growth during brittle fracture in compression, PhD thesis, Mass. Inst. of Technology (1965). C. H. Scholz,Experimental study of the fracturing process in brittle rock, J. Geophys. Res.73 (1968), 1447. H. E. McKinstry,Structural control of ore deposition in fissure veins, Amer. Inst. Min. Met. Engr. Tech. Pub. No. 1267, Mining Technology (Jan., 1941), 25 pp. E. T. Brown andJ. A. Hudson,Progressive collapse of simple block-jointed systems, Australian Geomechanics Jour.22 (1972), 49. D. Tocher,Anisotropy in rocks under simple compression, Trans. Amer. Geophys. Un.38 (1957), 89. S. Matsuchima,Variation of the elastic wave velocities of rocks in the process of deformation and fracture under high pressure, J. Physics of the Earth8, Kyoto Univ. Bull. No. 32 (1960), 1. W. F. Brace andA. S. Orange,Electrical resistivity changes in saturated rocks during fracture and frictional sliding, J. Geophys. Res.73 (1968), 1433. A. Nur,Dilatancy, pore fluids, and premonitory variations of t s /t p travel times, Bull. Seismol. Soc. Amer.62 (1972), 1217. C. H. Scholz, L. R. Sykes andY. P. Aggarwal,Earthquake prediction: A physical basis, Science181 (1973), 803. W. F. Brace,Current laboratory studies pertaining to earthquake prediction, Techonophysics6 (1968), 75. D. L. Anderson andJ. H. Whitcomb,The dilatancy-diffusion model of earthquake prediction, Proc. Conf. on Tectonic Problems of the San Andreas Fault System, edited byR. L. Kovach andA. Nur, Stanford Univ. Publ. XIII (1973), 417. K. Hadley,Laboratory investigation of dilatancy and motion on fault surfaces at low confining pressures, Proc. Conf. on Tectonic Problems of the San Andreas Fault System, edited byR. L. Kovach andA. Nur, Stanford Univ. Publ. XIII (1973), 427. W. F. Brace,Dilatancy-related electrical resistivity changes in rocks, this issue Pure and Appl. Geophys.112 (1974), 701. B. Brady,Theory of earthquakes, Part I, A scale independent theory of rock failure Pure and Appl. Geophys. (in press). K. Mogi,Regularities in the spatial and temporal distribution of large earthquakes and earthquake prediction, inSymposium on Earthquake Forerunners Searching Tashkent, USSR (1974). W. S. Stuart,Diffusionless dilatancy model for earthquake precursors, Geophys. Res. Letters Vol.,1 (1974), 261. V. F. Bouchkovskij,Izmenenio gradienta electricheskogo potenziala atmospheri kak odin iz vos mogenich predvestnikov zemletria senij, Problemi prognoza zemletriasenij, Moskva, Uzdatelstvo A.N. SSSR (1954).