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A study of ULF wave foreshock morphology—I: ULF foreshock boundary
Planetary and Space Science, 1992Abstract We have used ISEE 1 and 2 magnetometer data to determine the forward boundary of the upstream ULF wave foreshock. We first examine the presence and absence of ULF waves immediately upstream from the bow shock. The statistical results show that the ULF foreshock starts at θBn ∼ 50° on the bow shock, and fills the entire upstream region ...
G. Le, C.T. Russell
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Foreshocks and earthquake prediction
Tectonophysics, 1972Abstract If a group of foreshocks can be distinguished from ordinary seismic activities, it would contribute to earthquake prediction. In the case of two Japanese earthquakes, which were preceded by immediate foreshocks, the coefficient “b” in the magnitude versus frequency equation was significantly smaller than that of the aftershocks or of the ...
Shigeji Suyehiro, Hiroshi Sekiya
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Advances in Space Research, 1995
An overview of the observations of backstreaming electrons in the foreshock and the mechanisms that have been proposed to explain their properties will be presented. A primary characteristic of observed foreshock electrons is that their velocity distributions are spatially structured in a systematic way depending on distance from the magnetic field ...
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An overview of the observations of backstreaming electrons in the foreshock and the mechanisms that have been proposed to explain their properties will be presented. A primary characteristic of observed foreshock electrons is that their velocity distributions are spatially structured in a systematic way depending on distance from the magnetic field ...
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MMS observations of wave activity in the particle foreshock bubble foreshock region
2020<p>Foreshock bubbles (FBs) are kinetic transient phenomena formed due to the interaction between IMF discontinuities and backstreaming energetic ions in Earth&#8217;s foreshock region. FBs can be driven by both rotational discontinuities and tangential discontinuities and are typically observed under higher solar wind ...
Mengmeng Wang, Quanqi Shi
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Foreshocks of strong earthquakes
Izvestiya, Physics of the Solid Earth, 2014The specific enhancement of ultra-low-frequency (ULF) electromagnetic oscillations a few hours prior to the strong earthquakes, which was previously mentioned in the literature, motivated us to search for the distinctive features of the mechanical (foreshock) activity of the Earth’s crust in the epicentral zones of the future earthquakes. Activation of
A. V. Guglielmi +3 more
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Foreshocks and earthquake prediction
Tectonophysics, 1975Abstract Results of a statistical investigation of the magnitude and time distributions of foreshocks in the area of Greece are reported. Further evidence is presented that the parameter b , in the frequency—magnitude relation, has a smaller value before than after the main shock, and that the time distribution of foreshocks follows a statistical ...
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Foreshock Occurrence in Central California
Seismological Research Letters, 1979The hypocentral regions of 29 (M ≥ 3.5) earthquakes along the San Andreas fault system in central California have been systematically examined for increased microearthquake activity preceding the main shock. Of 20 shallow (h > 9 km) main events, 10 were preceded by an apparent buildup of seismic activity.
K. P. Kodama, C. G. Bufe
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1985
ISEE particle and wave data are noted to furnish substantial support for the basic features of the velocity dispersed model at the foreshock boundary that was proposed by Filbert and Kellogg (1979). Among many remaining discrepancies between this model and observation, it is noted that unstable reduced velocity distributions have been discovered behind
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ISEE particle and wave data are noted to furnish substantial support for the basic features of the velocity dispersed model at the foreshock boundary that was proposed by Filbert and Kellogg (1979). Among many remaining discrepancies between this model and observation, it is noted that unstable reduced velocity distributions have been discovered behind
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Foreshock Rates from Aftershock Abundance
Bulletin of the Seismological Society of America, 2008The question whether foreshocks behave like mainshocks that happen to have larger aftershocks is important for the understanding of earthquake nucleation and the modeling of earthquake clustering. Many models, including the short-term earthquake probability (STEP) model, for forecasting short-term earthquake hazard in California, and the epidemic-type ...
A. Christophersen, E. G. C. Smith
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Probing the foreshock wave boundary
2023Foreshock ultralow frequency (ULF) waves play an important role in the dynamics upstream of planetary bow shocks and can affect the downstream magnetosheath region.  Due to limited available spacecraft measurements, the waves are often analyzed with incomplete information about their overall spacial structure.
Seth Dorfman +4 more
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