Periodic slow slip triggers megathrust zone earthquakes in northeastern Japan

Uchida, Naoki; Iinuma, Toshitaka; Nadeau, R. M.; Bürgmann, Roland; Hino, Ryota

doi:10.1126/science.aad3108

Cited by 149 publications

(170 citation statements)

References 41 publications

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“…Comparing between the results of different sub-time-windows, swath widths and components may help us to distinguish long-term non-tectonic deformation from the tectonic deformation. Recently, Uchida et al (2016) revealed the periodic changes in the interplate coupling in the NE Japan subduction zone based primarily on the activity of small repeating earthquakes. They found that slow slip on the plate interface had occurred repeatedly at intervals of 1-6 yr, depending on the location.…”

Section: Discussionmentioning

confidence: 99%

Monitoring of the spatio-temporal change in the interplate coupling at northeastern Japan subduction zone based on the spatial gradients of surface velocity field

Iinuma

2017

Geophysical Journal International

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S U M M A R YA monitoring method to grasp the spatio-temporal change in the interplate coupling in a subduction zone based on the spatial gradients of surface displacement rate fields is proposed. I estimated the spatio-temporal change in the interplate coupling along the plate boundary in northeastern (NE) Japan by applying the proposed method to the surface displacement rates based on global positioning system observations. The gradient of the surface velocities is calculated in each swath configured along the direction normal to the Japan Trench for time windows such as 0.5, 1, 2, 3 and 5 yr being shifted by one week during the period of 1997-2016. The gradient of the horizontal velocities is negative and has a large magnitude when the interplate coupling at the shallow part (less than approximately 50 km in depth) beneath the profile is strong, and the sign of the gradient of the vertical velocity is sensitive to the existence of the coupling at the deep part (greater than approximately 50 km in depth). The trench-parallel variation of the spatial gradients of a displacement rate field clearly corresponds to the trenchparallel variation of the amplitude of the interplate coupling on the plate interface, as well as the rupture areas of previous interplate earthquakes. Temporal changes in the trench-parallel variation of the spatial gradient of the displacement rate correspond to the strengthening or weakening of the interplate coupling. We can monitor the temporal change in the interplate coupling state by calculating the spatial gradients of the surface displacement rate field to some extent without performing inversion analyses with applying certain constraint conditions that sometimes cause over-and/or underestimation at areas of limited spatial resolution far from the observation network. The results of the calculation confirm known interplate events in the NE Japan subduction zone, such as the post-seismic slip of the 2003 M8.0 Tokachi-oki and 2005 M7.2 Miyagi-oki earthquakes and the recovery of the interplate coupling around the rupture area of the 1994 M7.6 Sanriku-Haruka-oki earthquake. The results also indicate the semi-periodic occurrence of slow slip events and the expansion of the area of slow slip events before the 2011 Tohoku-oki earthquake (M9.0) approaching the hypocentre of the Tohoku-oki earthquake.

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Section: Discussionmentioning

confidence: 99%

Monitoring of the spatio-temporal change in the interplate coupling at northeastern Japan subduction zone based on the spatial gradients of surface velocity field

Iinuma

2017

Geophysical Journal International

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“…These events are usually attributed to the repeated rupture of small patches on a homogeneous and stably sliding background. There may exist a multiscale structure of stable patches behind them, but it would be difficult to observe this complex structure within the limited period of the seismic cycle (Uchida et al 2016). Nevertheless, the long-term observation of slip-deficit evolution and differences in amplitude for repeating events may provide further insight into the complex structure of the plate interface.…”

Section: Discussionmentioning

confidence: 99%

Role of multiscale heterogeneity in fault slip from quasi-static numerical simulations

Aochi

Ide

2017

Earth Planets Space

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Quasi-static numerical simulations of slip along a fault interface characterized by multiscale heterogeneity (fractal patch model) are carried out under the assumption that the characteristic distance in the slip-dependent frictional law is scale-dependent. We also consider slip-dependent stress accumulation on patches prior to the weakening process. When two patches of different size are superposed, the slip rate of the smaller patch is reduced when the stress is increased on the surrounding large patch. In the case of many patches over a range of scales, the slip rate on the smaller patches becomes significant in terms of both its amplitude and frequency. Peaks in slip rate are controlled by the surrounding larger patches, which may also be responsible for the segmentation of slip sequences. The use of an explicit slip-strengthening-then-weakening frictional behavior highlights that the strengthening process behind small patches weakens their interaction and reduces the peaks in slip rate, while the slip deficit continues to accumulate in the background. Therefore, it may be possible to image the progress of slip deficit at larger scales if the changes in slip activity on small patches are detectable.

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“…Most large interplate thrust earthquakes occurred in high-velocity areas that may represent high-strength asperities (Huang and Zhao 2013); In contrast, a low-velocity area associated with abundant sediments supplied from the incoming plate lies off Kamaishi (Tsuru et al 2002;Huang and Zhao 2013). Weak interplate locking off Kamaishi is also implied by the degree of periodicity and the dominant period of slow slip (Uchida et al 2016). The absence of large earthquakes in the areas adjacent to the coring sites owing to these tectonic settings has likely facilitated the successive recording of the great-giant earthquakes in the cores.…”

Section: Sensitivity Of Turbidity Current Generation To Earthquake Grmentioning

confidence: 99%

Supercycle in great earthquake recurrence along the Japan Trench over the last 4000 years

et al. 2018

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On the landward slope of the Japan Trench, the mid-slope terrace (MST) is located at a depth of 4000-6000 m. Two piston cores from the MST were analyzed to assess the applicability of the MST for turbidite paleoseismology and to find out reliable recurrence record of the great earthquakes along the Japan Trench. The cores have preserved records of ~ 12 seismo-turbidites (event deposits) during the last 4000 years. In the upper parts of the two cores, only the following earthquakes (magnitude M ~ 8 and larger) were clearly recorded: the 2011 Tohoku, the 1896 Sanriku, the 1454 Kyotoku, and the 869 Jogan earthquake. In the lower part of the cores, turbidites were deposited alternately in the northern and southern sites during the periods between concurrent depositional events occurring at intervals of 500-900 years. Considering the characteristics of the coring sites for their sensitivity to earthquake shaking, the concurrent depositional events likely correspond to a supercycle that follows giant (M ~ 9) earthquakes along the Japan Trench. Preliminary estimations of peak ground acceleration for the historical earthquakes recorded as the turbidites imply that each rupture length of the 1454 and 869 earthquakes was over 200 km. The earthquakes related to the supercycle have occurred over at least the last 4000 years, and the cycle seems to have become slightly shorter in recent years. Earthquakes off the Sanriku coast forming the alternative deposition of turbidites in the two cores have released a part of accumulated slip, as indicated by the turbidites deposited in only one core. Decreases in the release of accumulated slip have possibly caused the recent shortening of the supercycle.

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Periodic slow slip triggers megathrust zone earthquakes in northeastern Japan

Cited by 149 publications

References 41 publications

Monitoring of the spatio-temporal change in the interplate coupling at northeastern Japan subduction zone based on the spatial gradients of surface velocity field

Monitoring of the spatio-temporal change in the interplate coupling at northeastern Japan subduction zone based on the spatial gradients of surface velocity field

Role of multiscale heterogeneity in fault slip from quasi-static numerical simulations

Supercycle in great earthquake recurrence along the Japan Trench over the last 4000 years

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