Journal ArticleDOI
A tectonomagnetic effect observed before a magnitude 5.2 earthquake near Hollister California
B. E. Smith,M. J. S. Johnston +1 more
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In this paper, the most significant local changes during 1974 were recorded at a site 11 km from a magnitude 5.2 earthquake that occurred on November 28, 1974, lasting about 2 weeks.Abstract:
Simultaneous measurements of geomagnetic field with an array of seven proton precession magnetometers along the San Andreas fault show that the most significant local changes during 1974 were recorded at a site 11 km from a magnitude 5.2 earthquake that occurred on November 28, 1974. A systematic increase in magnetic field of 0.9 γ occurred at this site during the early part of 1974. A more dramatic increase of 1.5 γ occurred about 7 weeks before the earthquake, lasting about 2 weeks. Four weeks prior to the earthquake the magnetic field returned to approximately its initial value and remained at this value through April 1975. These data cannot be explained by ionospheric disturbances or telluric currents. The most probable source is a piezomagnetic effect, which implies that the magnetic field changes represent changes in stress in the rocks nearby the anomalous station.read more
Citations
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A systematic compilation of earthquake precursors
TL;DR: In this paper, a survey of published scientific literature was undertaken to identify and catalog observed earthquake pre- cursors, including electric and magnetic fields, gas emissions, groundwater level changes, temperature changes, surface deformations, and seismicity.
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Theory of electrokinetic‐magnetic anomalies in a faulted half‐space
TL;DR: In this article, the authors proposed that the magnetic field changes associated with the Matsushiro earthquake swarms were produced by electrokinetic currents, and they used electric field sensors to help in determining the source of any observed variations.
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Anomalous behaviors of geomagnetic diurnal variations prior to the 2011 off the Pacific coast of Tohoku earthquake (Mw9.0)
TL;DR: In this article, a 10-day running mean of the ratios showed a clear anomaly exceeding the statistical threshold in the vertical component about 2 months before the 2011 off the Pacific coast of Tohoku earthquake (Mw9.0) was reported.
Journal ArticleDOI
Plausibility of long distance electrotelluric precursors to earthquakes
TL;DR: In this article, a systematic analysis of the plausibility of different classes of models which could account for low-frequency precursory electrotelluric signals observable at large distances from a large earthquake is carried out.
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Slow earthquakes and stress redistribution
TL;DR: In this article, slow earthquakes provide a mechanism for stress redistribution before normal earthquakes, where stress concentration may take place just hours or days before an earthquake; if it did, this would affect prediction capability.
References
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Journal ArticleDOI
The processes preceding strong earthquakes in some regions of middle Asia
M.A. Sadovsky,I.L. Nersesov,S.K. Nigmatullaev,L.A. Latynina,A.A. Lukk,A.N. Semenov,I.G. Simbireva,V.I. Ulomov +7 more
TL;DR: In this article, the reliability of prediction, made on the basis of noted anomalies of some parameters, is estimated, and an example of prediction of place, energy and time of the earthquake as well as the estimation of the error of prediction is given using anomalies of the ratios of longitudinal and shear wave velocities.
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Theory of the piezomagnetic effect in titanomagnetite-bearing rocks
TL;DR: In this article, the stress sensitivities of titanomagnetite-bearing rocks are calculated in terms of magnetostriction constantsλ100 andλ111 and anisotropy constantsK1,K2 of the magnetic minerals.
Journal ArticleDOI
Basic magnetic properties of rocks under the effects of mechanical stresses
TL;DR: In this article, the effects of mechanical stresses on the magnetization of the earth's crust can be classified in two categories: (a) the reversible effect which disappears when the stress is removed; and (b) the irreversible effect which causes an irreversible enhancement or an irreversible demagnetization of remanent magnetization.
Journal ArticleDOI
Electrical Resistivity Variations Associated with Earthquakes on the San Andreas Fault
Aldo Mazzella,H. Frank Morrison +1 more
TL;DR: The character and duration of the precursor period agree well with those of other earthquake studies and support a dilatant earthquake mechanism model.
Journal ArticleDOI
Spatial and temporal variations in ts /tp and in P wave residuals at Blue Mountain Lake, New York: Application to earthquake prediction
TL;DR: In this paper, the travel time ratio of S to P waves (ts/tp) in real-time and to test the ts/tp technique as a predictive tool was used.