A water wall in the Tohoku forearc causing large crustal earthquakes

Zhao, Dapeng; Kitagawa, Hirohisa; Toyokuni, Genti

doi:10.1093/gji/ggu381

Cited by 58 publications

(69 citation statements)

References 77 publications

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“…The fluids promote mass circulation within a subduction channel and a mantle wedge. Ascending aqueous fluids, possibly jadeite-forming fluids, in a mantle wedge is also supported by a vertical wall-like low-V zones in the forearc region visualized by a high-resolution seismic tomography of NE Japan ('Water Wall': Zhao et al, 2015).…”

Section: Perspectivesmentioning

confidence: 85%

Jadeitite (jadeite jade) from Japan: History, characteristics, and perspectives

Tsujimori

Harlow

2017

Journal of Mineralogical and Petrological Sciences

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Jadeitite, known as 'hisui' in Japan, has been esteemed as sacred stone in both ancient and modern Japanese cultures. Although it was thought that the source material of Japanese jadeitite was brought from China, the identification of jadeite in 1939 changed this interpretation. Japanese jadeitites and jadeite-rich metasomatic rocks are found in Paleozoic and also Mesozoic geotectonic units. All localities are situated in serpentinite mélange with high-pressure metamorphic rocks and/or serpentinite lenses within a high-pressure metamorphosed complex. Outcrop exposures of contact between jadeitite and host serpentinite are extremely rare. Normally the jadeitites show lithological heterogeneity in the same locality due to multiple deformation, recrystallization, and metasomatic fluid infiltration. Studies over the last two decades have interpreted jadeitite in worldwide either as the direct aqueous fluid precipitate (P-type) from subduction channel into the overlying mantle wedge, as the metasomatic replacement (R-type) by such fluids of oceanic plagiogranite, graywacke, or metabasite along the channel margin, or a combination of these two processes. Japanese jadeitites are classified into one or the other type. Multiple stable isotope characterization analyses for jadeitite and related metasomatic rocks and serpentinite become increasingly important to decode fluid behaviors in past subduction zone. However, available geochemical data on Japanese jadeitite are very limited in comparison with other studied localities. More systematic research will unlock new insights about fluid flow and its impacts at the bottom of forearc mantle where jadeitites form. Chemical differentiation and transportation of the fluids involved in jadeititeformation are crucial topics requiring further research. Nevertheless, the designation of jadeite (and jadeitite) as the national stone of Japan by the Japan Association of Mineralogical Sciences in 2016 should bolster education of the public about this revered stone and its role in subduction zone processes.

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Section: Perspectivesmentioning

confidence: 85%

Jadeitite (jadeite jade) from Japan: History, characteristics, and perspectives

Tsujimori

Harlow

2017

Journal of Mineralogical and Petrological Sciences

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“…Many workers have investigated the 3-D seismic velocity structure in the source areas of large crustal earthquakes which occurred in various tectonic settings, and the results show that the nucleation of all the large crustal earthquakes was affected (or controlled) by structural heterogeneities in the crust and uppermost mantle (e.g., Mishra and Zhao 2003;Zhao 2004, 2009;Qi et al 2006;Lei and Zhao 2009;Xu and Zhao 2009;Chen et al 2014; Cheng et al 2011Cheng et al , 2014. For some large crustal earthquakes in subduction zones, structural heterogeneities in the focal area are associated with arc fluids and magmas caused by dehydration of the subducting slab and corner flow in the mantle wedge (e.g., Ikeda et al 2006;Wang and Zhao 2006;Xia et al 2008;Zhao et al 2010Zhao et al , 2011aZhao et al , 2015Cheng et al 2011;Padhy et al 2011;Tong et al 2011Tong et al , 2012. It is also found that the nucleation of the great 2011 Tohoku-oki earthquake (Mw 9.0) and other megathrust earthquakes (M > 7.0) was affected by structural heterogeneities in the interplate megathrust zone under the fore-arc regions, which may reflect the subducted sediments and seamounts, as well as fluids from the slab dehydration (e.g., Zhao et al 2011b;Huang and Zhao 2013a, b;Liu et al 2013aLiu et al , b, 2014.…”

Section: Mantle Heterogeneity and Deep Moonquakesmentioning

confidence: 87%

“…By definition, Poisson's ratio is the ratio of the radial contraction to axial elongation, and it is more sensitive to compositional variations and content of fluids and melts than Vp and Vs alone, and so it is a very useful parameter in studying the physical and petrologic properties of the crust and mantle (e.g., Christensen 1996;Zhao et al 1996). When crustal fluids exist in an earthquake source area or a hot magma chamber exists under an active volcano, they can be detected as low-V and high-σ anomalies by high-resolution local tomography (e.g., Zhao et al 1996Zhao et al , 2015Mishra and Zhao 2003;Cheng et al 2011). Figures 8.19 and 8.20 show the estimated Poisson's ratio images of the lunar interior .…”

Section: Lunar Tomographic Imagesmentioning

confidence: 99%

Seismic Tomography of the Moon

Zhao¹

2015

Multiscale Seismic Tomography

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Moonquake arrival-time data recorded by the Apollo seismic network operated during 1969 to 1977 have been used to determine P-and S-wave velocity tomography of the crust and mantle beneath the lunar near-side. The results have shown that significant lateral heterogeneities may exist in the lunar interior. A correlation between the S-wave tomography and the thorium abundance distribution is revealed. The area with high thorium abundance exhibits a distinct low shear-velocity which extends down to a depth of ~ 300 km below the Procellarum KREEP Terrane (PKT), which may reflect a thermal and compositional anomaly under the PKT. The distribution of deep moonquakes shows a correlation with the tomography in the deep lunar mantle, similar to earthquakes which are affected by structural heterogeneities in the terrestrial crust and upper mantle. The presence of deep moonquakes and seismic-velocity heterogeneity implies that the interior of the present Moon may still be thermally and dynamically active. Although lunar tomography is still preliminary, it indicates that tomographic imaging of the lunar interior is feasible.

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“…The P-T conditions of jadeitites correlate to forearc mantle wedge and HP-LT metamorphism within a Pacific-type subduction zone at relatively shallow depths (<~100 km). Ascending aqueous fluids in a mantle wedge are also supported by a vertical wall-like low-V zones in the forearc region visualized by a high-resolution seismic tomography of NE Japan ('Water Wall': Zhao et al, 2015). The jadeiteforming aqueous fluids transfer various elements from subduction slab into the transitional mélange and overlying mantle wedge (e.g., Flores et al, 2013;Harlow et al, 2016); these fluids also promote mass circulation within a subduction channel and mantle wedge.…”

Section: Perspectivesmentioning

confidence: 96%

Early Paleozoic jadeitites in Japan: An overview

Tsujimori

2017

Journal of Mineralogical and Petrological Sciences

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Paleozoic jadeitite-bearing serpentinite-matrix mélange represents the oldest mantle wedge record of a Pacifictype subduction zone of proto-Japan. Most jadeitites are fluid precipitates (P-type), but some jadeitites are metasomatic replacement (R-type) which preserve relict minerals and protolith textures. The beauty and preciousness of some gem-quality, semi-translucent varieties of jadeitites in the Itoigawa-Omi area led to the designation of jadeitite as the national stone of Japan by the Japan Association of Mineralogical Sciences. Zircon geochronology indicates jadeitite formed prior to Late Paleozoic Renge metamorphism that formed blueschist and rare eclogite. For example, in the Itoigawa-Omi and Osayama localities, older jadeitites and younger high-pressure/ lowtemperature metamorphic rocks in a single mélange complex imply different histories for the subduction channel and jadeite-bearing serpentinite-matrix mélange. This suggests that the jadeitite-hosted mélange (or serpentinized peridotite) can stay within the mantle wedge for a considerable time; thus recrystallization, resorption, and re-precipitation of jadeitite can continue in the mantle wedge environment. Therefore, studies of Paleozoic jadeitites in Japan have great potential to elucidate the earliest stages of orogenic growth (oceanward-accretion and landward-erosion) associated with the subduction of the paleo-Pacific oceanic plates, and to test geophysical observations of modern analogues from a mixture of fossilized mantle wedges and subduction channels.

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A water wall in the Tohoku forearc causing large crustal earthquakes

Cited by 58 publications

References 77 publications

Jadeitite (jadeite jade) from Japan: History, characteristics, and perspectives

Jadeitite (jadeite jade) from Japan: History, characteristics, and perspectives

Seismic Tomography of the Moon

Early Paleozoic jadeitites in Japan: An overview

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