Earthquakes and fractures

Mogi, Kiyoo

doi:10.1016/0040-1951(67)90043-1

Cited by 276 publications

(130 citation statements)

References 14 publications

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“…The b-values of the power-law portions of each distribution, however, remained constant. In our model, by contrast, both thc degree of enhancement and the b-value vary systematically with heterogeneity; the latter has also been observed in acoustic emission experiments [Mogi, 1967] The observation that heterogeneity is required to stop rupture supports both the contention [Rice, 1993] …”

Section: Discussionsupporting

confidence: 78%

Heterogeneity and the earthquake magnitude‐frequency distribution

Steacy¹,

McCloskey²

1999

Geophysical Research Letters

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Section: Discussionsupporting

confidence: 78%

Heterogeneity and the earthquake magnitude‐frequency distribution

Steacy¹,

McCloskey²

1999

Geophysical Research Letters

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“…Strong support for this idea has been obtained by recent statistical earthquake and fracture studies e.g. in Japan (Mogi 1967). In this connection it might be necessary to point out that the compilation of the fracture-tectonic map was done without any comparison to the seismic map (Fig.…”

Section: Fracture-tectonicsmentioning

confidence: 92%

Structural position of ore-bearing areas in Finland

Mikkola¹,

Niini²

1968

Bull Geol Soc Finland

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The Finnish ore deposits of the economically most important metals -mainly Cu, Fe, Ni, Pb, Ti and Zn -are grouped according to their metal content. This grouping closely follows the genetic classification of the ore deposits. A really the ore deposits in Finland are concentrated into four elongated zones, each of which probably contains several metallogenic provinces. The location of the zones shows a close relationship to structural features, especially fault zones and to the location of basic intrusive rocks. There seems to be a negative correlation between the zones and the areas of granitic rocks. This is explained as meaning that the concentration of the ore material has followed deapseated and extensive fault zones. CONTENTS

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“…Case histories analyze individual foreshock sequences, most of them being chosen a posteriori to suggest that foreshock patterns observed in acoustic emissions preceding rupture in the laboratory could apply to earthquakes [Mogi, 1963;1967]. A few statistical tests validate the significance of reported anomalies on b-value of foreshocks.…”

Section: Magnitude Distribution Of Foreshocksmentioning

confidence: 99%

“…But because aftershocks exist on all scales, from the laboratory scale, e.g. [Mogi, 1967;Scholz, 1968], to the worldwide seismicity, we may expect that all earthquakes, whatever their magnitude, trigger their own aftershocks, but with a rate increasing with the mainshock magnitude, so that only aftershocks of the largest earthquakes are identifiable unambiguously.…”

Section: Introductionmentioning

confidence: 99%

Mainshocks are aftershocks of conditional foreshocks: How do foreshock statistical properties emerge from aftershock laws

2003

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The inverse Omori law for foreshocks discovered in the 1970s states that the rate of earthquakes prior to a mainshock increases on average as a power law ∝ 1/(t c − t) p ′ of the time to the mainshock occurring at t c . Here, we show that this law results from the direct Omori law for aftershocks describing the power law decay ∼ 1/(t − t c ) p of seismicity after an earthquake, provided that any earthquake can trigger its suit of aftershocks. In this picture, the seismic activity at any time is the sum of the spontaneous tectonic loading and of the activity triggered by all preceding events weighted by their corresponding Omori law. The inverse Omori law then emerges as the expected (in a statistical sense) trajectory of seismicity, conditioned on the fact that it leads to the burst of seismic activity accompanying the mainshock. In particular, we predict and verify by numerical simulations on the Epidemic-Type-Aftershock Sequence (ETAS) model that p ′ is always smaller than or equal to p and a function of p, of the b-value of the Gutenberg-Richter law (GR) and of a parameter quantifying the number of direct aftershocks as a function of the magnitude of the mainshock. The often documented apparent decrease of the b-value of the GR law at the approach to the main shock results straightforwardly from the conditioning of the path of seismic activity culminating at the mainshock. However, we predict that the GR law is not modified simply by a change of b-value but that a more accurate statement is that the GR law gets an additive (or deviatoric) power law contribution with exponent smaller than b and with an amplitude growing as a power law of the time to the mainshock. In the space domain, we predict that the phenomenon of aftershock diffusion must have its mirror process reflected into an inward migration of foreshocks towards the mainshock. In this model, foreshock sequences are special aftershock sequences which are modified by the condition to end up in a burst of seismicity associated with the mainshock. Foreshocks are not 2 just statistical creatures, they are genuine forerunners of large shocks as shown by the large prediction gains obtained using several of their qualifiers.

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Earthquakes and fractures

Cited by 276 publications

References 14 publications

Heterogeneity and the earthquake magnitude‐frequency distribution

Heterogeneity and the earthquake magnitude‐frequency distribution

Structural position of ore-bearing areas in Finland

Mainshocks are aftershocks of conditional foreshocks: How do foreshock statistical properties emerge from aftershock laws

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