Migration of crustal deformation

Kasahara, Keichi

doi:10.1016/0040-1951(79)90240-3

Cited by 79 publications

(36 citation statements)

References 12 publications

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“…Among them, those based on post-seismic viscoelastic relaxation explain triggering at distances of the order of 100 of kilometers with delays of some years (Viti et al 2003). Another class of models involves transient crustal deformation at the level of entire plates or portions of plates (Kasahara 1979). Finally, other authors invoke mechanisms that are external to the lithosphere.…”

Section: Discussionmentioning

confidence: 99%

A Statistical Investigation on a Seismic Transient Occurred in Italy Between the 17th and 20th Centuries

Bragato

2016

Pure Appl. Geophys.

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Abstract-According to the historical earthquake catalog of Italy, the country experienced a pulse of seismicity between the 17th century, when the rate of destructive events increased by more than 100%, and the 20th century, characterized by a symmetric decrease. In the present work, I performed a statistical analysis to verify the reliability of such transient, considering different sources of bias and uncertainty, such as completeness and declustering of the catalog, as well as errors on magnitude estimation. I also searched for a confirmation externally to the catalog, analyzing the correlation with the volcanic activity. The similarity is high for the eruptive history of Vesuvius, which agrees on both the main rate changes of the 17th and 20th centuries and on minor variations in the intermediate period. Of general interest, beyond the specific case of Italy, the observed rate changes suggest the existence of large-scale crustal processes taking place within decades and lasting for centuries, responsible for the synchronous activation/ deactivation of remote, loosely connected faults in different tectonic domains. Although their origin is still unexplained (I discuss a possible link with the climate changes and the consequent variations of the sea level), their existence and long lasting is critical for seismic hazard computation. In fact, they introduce a hardly predictable time variability that undermines any hypothesis of regularity of the earthquake cycle on individual faults and systems of interconnected faults.

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Section: Discussionmentioning

confidence: 99%

A Statistical Investigation on a Seismic Transient Occurred in Italy Between the 17th and 20th Centuries

Bragato

2016

Pure Appl. Geophys.

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“…The direct methods exploring temporal variations of crustal deformation comprise the deformographic (Kasahara, 1979;Ishii et al, 1983;Nevskii et al, 1987;Bella et al, 1990;Harada et al, 2003), hydrogeodynamic (Barabanov et al, 1988;Kissin, 2008) and geodetic measurements (Kuz'min, 2012), including the methods of deformation measurements using laser ranging (Milyukov et al, 2013) and GPS observations (Reuveni et al, 2014;Yoshioka et al, 2015).…”

Section: Methods For Detection Of Slow Strain Wavesmentioning

confidence: 99%

“…Migration of earthquake epicenters coincides with the velocity (10-100 km yr −1 ) and direction of crustal deformation movement (Kasahara, 1979;Barabanov et al, 1988) and with hydrological effects (Kissin, 2008). Furthermore, the absorption and dispersion of the waveforms of migrating deformation were detected (Kasahara, 1979;Barabanov et al, 1988), i.e., the main properties of a common wave process. In terms of the physical mechanism of propagation, slow strain waves are similar to common seismic waves, but the fundamental difference is that they propagate at super low velocities and ultra low frequencies, and have large wavelengths (Bykov, 2005).…”

Section: Introductionmentioning

confidence: 94%

“…By now, the deformographic, geodetic and hydrological measurements performed worldwide have revealed the migration of deformations at velocities of about 10-100 km yr −1 and 1-10 km day −1 (Kasahara, 1979;Bella et al, 1990;Harada et al, 2003;Kuz'min, 2012;Reuveni et al, 2014;Yoshioka et al, 2015). Migration of earthquake epicenters coincides with the velocity (10-100 km yr −1 ) and direction of crustal deformation movement (Kasahara, 1979;Barabanov et al, 1988) and with hydrological effects (Kissin, 2008). Furthermore, the absorption and dispersion of the waveforms of migrating deformation were detected (Kasahara, 1979;Barabanov et al, 1988), i.e., the main properties of a common wave process.…”

Section: Introductionmentioning

confidence: 97%

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Slow strain waves in blocky geological media from GPS and seismological observations on the Amurian plate

Быков

Trofimenko

2016

Nonlin. Processes Geophys.

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Abstract. Based on the statistical analysis of spatiotemporal distribution of earthquake epicenters and perennial geodetic observation series, new evidence is obtained for the existence of slow strain waves in the Earth. The results of our investigation allow us to identify the dynamics of seismicity along the northern boundary of the Amurian plate as a wave process. Migration of epicenters of weak earthquakes (2 ≤ M ≤ 4) is initiated by the east-west propagation of a strain wave front at an average velocity of 1000 km yr −1 . We have found a synchronous quasi-periodic variation of seismicity in equally spaced clusters with spatial periods of 3.5 and 7.26 • comparable with the length of slow strain waves. The geodetic observations at GPS sites in proximity to local active faults show that in a number of cases, the GPS site coordinate seasonal variations exhibit a significant phase shift, whereas the time series of these GPS sites differ significantly from a sinusoid. Based on experimental observation data and the developed model of crustal block movement, we have shown that there is one possible interpretation for this fact that the trajectory of GPS station position disturbance is induced by migration of crustal deformation in the form of slow waves.

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“…ZHANG (1987) given E = 10 5 MPa for the Young's modulus of the Earth's crust, viscosity constant g = 10 22 Pa s. WANG (1979) and MEI et al (1992) took viscosity constant 10 17 $ 10 23 Pa s and the Young's modulus of the Earth's crust 10 4 $ 10 5 MPa. KASAHARA (1979) took the viscosity constant g = 2 Â 10 21 Pa s. MATSU 'URA et al (1999) andFUKAHATA et al (2004) given the viscosity of 5 Â 10 18 Pa s.…”

mentioning

confidence: 99%

The Displacement and Strain Field of Three-dimensional Rheologic Model of Earthquake Preparation

Song¹,

Yin²,

Mei³

et al.

Pageoph Topical Volumes

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Abstract-Based on the three-dimensional elastic inclusion model proposed by Dobrovolskii, we developed a rheological inclusion model to study earthquake preparation processes. By using the Corresponding Principle in the theory of rheologic mechanics, we derived the analytic expressions of viscoelastic displacement U(r, t) , V(r, t) and W(r, t), normal strains e xx (r, t), e yy (r, t) and e zz (r, t) and the bulk strain h (r, t) at an arbitrary point (x, y, z) in three directions of X axis, Y axis and Z axis produced by a three-dimensional inclusion in the semi-infinite rheologic medium defined by the standard linear rheologic model. Subsequent to the spatial-temporal variation of bulk strain being computed on the ground produced by such a spherical rheologic inclusion, interesting results are obtained, suggesting that the bulk strain produced by a hard inclusion change with time according to three stages (a, b, c) with different characteristics, similar to that of geodetic deformation observations, but different with the results of a soft inclusion. These theoretical results can be used to explain the characteristics of spatial-temporal evolution, patterns, quadrant-distribution of earthquake precursors, the changeability, spontaneity and complexity of short-term and imminent-term precursors. It offers a theoretical base to build physical models for earthquake precursors and to predict the earthquakes.

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Migration of crustal deformation

Cited by 79 publications

References 12 publications

A Statistical Investigation on a Seismic Transient Occurred in Italy Between the 17th and 20th Centuries

A Statistical Investigation on a Seismic Transient Occurred in Italy Between the 17th and 20th Centuries

Slow strain waves in blocky geological media from GPS and seismological observations on the Amurian plate

The Displacement and Strain Field of Three-dimensional Rheologic Model of Earthquake Preparation

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