Initiation of the great Mw 9.0 Tohoku–Oki earthquake

Chu, Risheng; Wei, Sui; Helmberger, Donald V.; Zhan, Zhao; Zhu, Lupei; Kanamori, Hiroo

doi:10.1016/j.epsl.2011.06.031

Cited by 62 publications

(75 citation statements)

References 18 publications

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“…The most significant feature of the 2011 Tohoku-Oki earthquake is a huge coseismic slip (>50 m) near the trench axis that breached the trench. The rupture initiated about 110 km west of the trench axis at a depth of 21 km (Chu et al, 2011) and propagated both updip and downdip. The near-trench coseismic slip over 50 m has been estimated by several studies based on seismic data (e.g., Yagi and Fukahata, 2011), tsunami data (e.g., Fujii et al, 2011), and seafloor geodetic data (e.g., Ito et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Aftershocks near the updip end of the 2011 Tohoku-Oki earthquake

Obana

Kodaira

Shinohara

et al. 2013

Earth and Planetary Science Letters

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Section: Introductionmentioning

confidence: 99%

Aftershocks near the updip end of the 2011 Tohoku-Oki earthquake

Obana

Kodaira

Shinohara

et al. 2013

Earth and Planetary Science Letters

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“…The original CAP breaks long-period regional waveform data into P nl wave and surface-wave segments and shifts them independently to find the best waveform fits (Zhao and Helmberger, 1994;Zhu and Helmberger, 1996). A modification of the method for teleseismic waveform data has been successfully applied to earthquakes involving USArray and beneath Japan (Chu, Schmandt, Helmberger, 2012;Chu, Wei, et al 2012;Zhan et al, 2012). Because the crustal structures in the source and receiver regions are decoupled teleseismically, they are allowed to be distinct.…”

Section: Introductionmentioning

confidence: 99%

Source Parameters of the Shallow 2012 Brawley Earthquake, Imperial Valley

Chu

Helmberger

2013

Bulletin of the Seismological Society of America

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Resolving earthquake parameters, especially depth, is difficult for events occurring within basins because of issues involved with separating source properties from propagational path effects. Here, we demonstrate some advantages of using a combination of teleseismic and regional waveform data to improve resolution following a bootstrapping approach. Local SS-S differential arrivals from a foreshock are used to determine a local layered model which can then be used to model teleseismic depth phases: pP, sP, and sS. Using the cut-and-paste (CAP) method for which all strike (θ), dip (δ), rake (λ), and depth variations are sampled for several crustal models. We find that regional data prove the most reliable at fixing the strike, whereas the depth is better constrained by teleseismic data. Weighted solutions indicate a nearly pure strike-slip mechanism (θ 59° 1°) with a centroid depth of about 4.0 km and an M w of 5.4 for the mainshock of the 2012 Brawley earthquake. Online Material:Figures showing examples of waveform fits, comparison of synthetic teleseismic waveforms using different grid sizes in the FD calculation, effect of soft sediment on teleseismic Green's functions, and sensitivity of regional and teleseismic data on the focal mechanisms.

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“…• E. In the first several seconds, the rupture behaved like an ordinary small earthquake (Chu et al, 2011), but it eventually propagated through a wide region of the subduction plate boundary east of northern Honshu. In many studies, the area of largest slip, which is as much as 50 m or more, was located to the east of the hypocenter, possibly near the Japan Trench (e.g., Fujii et al, 2011;Ide et al, 2011;Ito et al, 2011;Yagi and Fukahata, 2011).…”

Section: Introductionmentioning

confidence: 99%

A scenario for the generation process of the 2011 Tohoku earthquake based on dynamic rupture simulation: Role of stress concentration and thermal fluid pressurization

2012

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We perform dynamic rupture simulations to improve the understanding of the generation process of the 2011 Tohoku earthquake. We assume a dynamic weakening mechanism (dynamic thermal pressurization of pore fluid, hereinafter called TP) on the fault plane to represent nonlinear weakening friction, and take into account the shear stress changes before the Tohoku earthquake, due to the four M 7-class earthquakes that occurred during [2003][2004][2005][2006][2007][2008][2009][2010][2011]. To constrain the dynamic rupture simulation, the moment release rate obtained by seismic slip inversions is referred. The simulation result implies the following about the 2011 Tohoku earthquake: (1) The rupture around the hypocenter was enhanced by the stress accumulation due to the preceding M 7-class earthquakes. (2) The enhanced rupture triggered the TP mechanism in the near-trench area causing large slip, which promoted propagation of the rupture over a wide region including the source areas of the M 7-class earthquakes and surrounding conditionally-stable areas. (3) Without sufficient stress accumulation, the moment release of the Tohoku earthquake ended as an M 8-class earthquake. (4) TP in the near-trench area should be effective but moderate. The occurrence time of the next megaquake would be strongly affected by the nonlinear effects of TP and the stress conditions. Thus, our model may contradict the concept of the (quasi-)cyclic occurrence of M 9 earthquakes.

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Initiation of the great Mw 9.0 Tohoku–Oki earthquake

Cited by 62 publications

References 18 publications

Aftershocks near the updip end of the 2011 Tohoku-Oki earthquake

Aftershocks near the updip end of the 2011 Tohoku-Oki earthquake

Source Parameters of the Shallow 2012 Brawley Earthquake, Imperial Valley

A scenario for the generation process of the 2011 Tohoku earthquake based on dynamic rupture simulation: Role of stress concentration and thermal fluid pressurization

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