Magnitude −7 level earthquakes: A new lower limit of self‐similarity in seismic scaling relationships

Yoshimitsu, N.; Kawakata, Hironori; Takahashi, Nobuo

doi:10.1002/2014gl060306

Cited by 60 publications

(58 citation statements)

References 43 publications

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“…Stress drops of small and large earthquakes have been investigated and have almost confirmed the selfsimilarity of earthquakes (e.g., Kanamori and Anderson 1975;Abercrombie 1995;Prieto et al 2004;Yamada et al 2007;Yoshimitsu et al 2014). This self-similarity is important in that we can treat stress drops of earthquakes as indicators of the difference between the shear strength and the dynamic stress level on the fault plane, independent of the earthquake size.…”

Section: Stress Drop and Its Mechanical Significancementioning

confidence: 80%

Spatial pattern in stress drops of moderate-sized earthquakes on the Pacific Plate off the south-east of Hokkaido, Japan: implications for the heterogeneity of frictional properties

Yamada

Saito

Tanioka

et al. 2017

Prog Earth Planet Sci

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We show that the spatial heterogeneity in the coseismic displacement of large earthquakes likely reflects the spatial characteristics of the frictional properties and that it can be inferred from the stress drop of moderate-sized earthquakes. We analyzed stress drops of 686 earthquakes with magnitudes of 4.0 to 5.0 off the south-east of Hokkaido, Japan, and investigated the spatial heterogeneity between the difference of shear strength and dynamic stress level on the Pacific Plate. We deconvolved observed P and S waves with those of collocated small earthquakes and derived the source effect of the earthquakes. We then estimated the corner frequencies of the earthquakes and calculated stress drops using a circular fault model. The values of stress drops showed a spatial pattern consistent with slip distributions of historical large earthquakes. Earthquakes that occurred in the area with a large coseismic slip during the , and the area acted as a barrier during the 2003 Tokachi-oki earthquake. These facts suggest that the frictional properties of the plate interface show little temporal change, and their spatial pattern can be monitored by stress drops of moderatesized earthquakes. The spatial heterogeneity provides important information for estimating the slip pattern of a future large earthquake and discussing a policy for disaster mitigation, especially for regions in which slip patterns of historical large earthquakes are unclear.

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Section: Stress Drop and Its Mechanical Significancementioning

confidence: 80%

Spatial pattern in stress drops of moderate-sized earthquakes on the Pacific Plate off the south-east of Hokkaido, Japan: implications for the heterogeneity of frictional properties

Yamada

Saito

Tanioka

et al. 2017

Prog Earth Planet Sci

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“…Stress drops of small and large earthquakes have been estimated to investigate the self-similarity of earthquakes (e.g., Abercrombie 1995; Kanamori and Anderson 1975;Prieto et al 2004;Yamada et al 2007). Recently, Yoshimitsu et al (2014) investigated acoustic emission (AE) events of a rock fracture experiment under seismogenic pressure conditions and pointed out that the AE events with magnitudes down to −8 satisfied the proportionality between the seismic moment and the corner frequency to the third power, or the constant stress drop. Another aspect of the stress drop analysis is the spatiotemporal heterogeneity of stress and strength.…”

Section: Studies On Seismicity and Stress Dropmentioning

confidence: 99%

Migration of earthquakes with a small stress drop in the Tanzawa Mountains, Japan

et al. 2015

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A cluster of earthquake activity took place beneath the Tanzawa Mountains at a depth of 20 km during the end of January 2012. The activity began at 22:39 UT on January 27 and included 78 earthquakes with magnitudes of 2.0 and greater within the span of 50 h. Five of them had magnitudes greater than 4.0, and the largest one was a M5.4 earthquake. We relocated the hypocenters by using the double-difference method and characterized their migrations away from the first earthquake of the cluster activity. The migration was consistent with fluid diffusion and had a similar speed to that of non-volcanic tremors and of induced earthquakes caused by water-injection experiments. We then analyzed stress drops for 16 earthquakes of M3.5 and greater that occurred from July 2003 to June 2012 in the area of the cluster activity. Earthquakes that occurred before and after the cluster activity had typical and stable values of stress drop. This is consistent with structural studies indicating the existence of little fluid in the region. In contrast, the cluster activity included earthquakes with significantly small stress drops. The leading hypothesis is that the cluster activity was associated with a decrease in the shear strength due to an increase in pore pressure, and this can explain both the migration of hypocenters and the small stress drops associated with the cluster activity. This hypothesis is also supported by the fact that earthquakes before and after the cluster activity had similar values of stress drop, thus suggesting that the activity was triggered by a different mechanism from the other earthquakes in the same region. The most plausible explanation is that there is a little fluid in the closed system beneath the Tanzawa Mountains that is undetectable by structural observations.

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“…3). A disagreement with a scaling of Δσ ∝ M 0 −1/4 is also observed for microearthquakes recorded at the SAFOD Pilot Hole at Parkfield (Imanishi and Ellsworth 2006) and repeating acoustic emission events from laboratory experiments (Yoshimitsu et al 2014). …”

Section: Discussionmentioning

confidence: 93%

“…Many studies have reported that the static stress drop is almost constant for the scale from natural earthquakes to acoustic emission events (e.g., Hiramatsu et al 2002;Imanishi and Ellsworth 2006;Yoshimitsu et al 2014). On the other hand, a spatial or temporal fluctuation of the static stress drop has often been recognized as well because the heterogeneity of stress and strength on a ruptured fault determines the value of the static stress drop (e.g., Shearer 2007, 2009;Hardebeck and Aron 2009;Oth 2013;Uchide et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Relationship between coseismic slip and static stress drop of similar aftershocks of the 2007 Noto Hanto earthquake

2015

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We have investigated the spatial distribution of the static stress drop of similar aftershocks of the 2007 Noto Hanto earthquake, central Japan, and have examined the relationship between the coseismic slip of the mainshock and the static stress drop of the similar aftershocks. The static stress drop is estimated by using the empirical Green's function method for P-and S-waves. The estimated static stress drop approximately ranges from 5 to 20 MPa, which is a typical range of values for tectonic earthquakes. The static stress drops of the aftershocks in a large slip area of the mainshock tend to be larger than those in a small slip area. This suggests a large difference between the strength and the dynamic stress level in the large slip area and a small difference in the small slip area if the final stress level is equal to the dynamic stress level.

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Magnitude −7 level earthquakes: A new lower limit of self‐similarity in seismic scaling relationships

Cited by 60 publications

References 43 publications

Spatial pattern in stress drops of moderate-sized earthquakes on the Pacific Plate off the south-east of Hokkaido, Japan: implications for the heterogeneity of frictional properties

Spatial pattern in stress drops of moderate-sized earthquakes on the Pacific Plate off the south-east of Hokkaido, Japan: implications for the heterogeneity of frictional properties

Migration of earthquakes with a small stress drop in the Tanzawa Mountains, Japan

Relationship between coseismic slip and static stress drop of similar aftershocks of the 2007 Noto Hanto earthquake

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