Mantle wedge structure in the Miyagi Prefecture forearc region, central northeastern Japan arc, and its relation to corner-flow pattern and interplate coupling

2011 ◽  
Vol 116 (B10) ◽  
Author(s):  
Yojiro Yamamoto ◽  
Ryota Hino ◽  
Masanao Shinohara
Keyword(s):  
Flow Pattern ◽  
Mantle Wedge ◽  
Corner Flow ◽  
Interplate Coupling ◽  
Northeastern Japan ◽  
Miyagi Prefecture ◽  
Wedge Structure ◽  
Forearc Region

scholarly journals Spatial heterogeneity of the mantle wedge structure and interplate coupling in the NE Japan forearc region

2008 ◽  
Vol 35 (23) ◽  
Author(s):  
Yojiro Yamamoto ◽  
Ryota Hino ◽  
Kensuke Suzuki ◽  
Yoshihiro Ito ◽  
Tomoaki Yamada ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Mantle Wedge ◽  
Interplate Coupling ◽  
Wedge Structure ◽  
Forearc Region ◽  
Ne Japan

scholarly journals Attenuation contrast in mantle wedge across the volcanic front of northeastern Japan that controls propagations of high-frequency S-wave later phases

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Takahiro Shiina ◽  
Kei Katsumata ◽  
Kiyoshi Yomogida ◽  
Aitaro Kato
Keyword(s):  
High Frequency ◽  
Mantle Wedge ◽  
Volcanic Front ◽  
S Wave ◽  
High Attenuation ◽  
Northeastern Japan ◽  
Pass Through ◽  
High Frequency Waves ◽  
Forearc Region ◽  
Ne Japan

AbstractDistinct later phases of waves with rich high-frequency (> 8 Hz) components were observed for intraslab earthquakes that occurred at intermediate depths, particularly at depths exceeding 100 km, in the northeastern (NE) Japan subduction zone. These high-frequency later phases (HFLPs) showed anomalously large peak-amplitude delays, up to ~ 50 s after direct S-wave arrivals at stations in the backarc region. Using a source-scanning algorithm, we investigated the locations of passing points affecting the propagation of HFLPs. The passing points were estimated to be in the forearc region in the entire NE Japan, indicating that HFLPs are scattered waves that pass through the forearc region. The propagating HFLPs seem to bypass the backarc mantle wedge, as a consequence of the distinct attenuation contrast in the mantle wedge across the volcanic front in NE Japan. These HFLP observations suggest that the high-attenuation zone in the backarc mantle wedge controls propagations of the high-frequency waves of intraslab earthquakes, in addition to the scatterers possibly locate in the forearc region.

scholarly journals Serpentine alteration as source of high dissolved silicon and elevated δ30Si values to the marine Si cycle

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Sonja Geilert ◽  
Patricia Grasse ◽  
Klaus Wallmann ◽  
Volker Liebetrau ◽  
Catriona D. Menzies
Keyword(s):  
Closed System ◽  
Isotope Fractionation ◽  
Mantle Wedge ◽  
Important Process ◽  
Sr Isotope ◽  
Element Cycling ◽  
High Fluid ◽  
Dissolved Silicon ◽  
Si Isotope ◽  
Forearc Region

Abstract Serpentine alteration is recognized as an important process for element cycling, however, related silicon fluxes are unknown. Pore fluids from serpentinite seamounts sampled in the Mariana forearc region during IODP Expedition 366 were investigated for their Si, B, and Sr isotope signatures (δ30Si, δ11B, and 87Sr/86Sr, respectively) to study serpentinization in the mantle wedge and shallow serpentine alteration to authigenic clays by seawater. While serpentinization in the mantle wedge caused no significant Si isotope fractionation, implying closed system conditions, serpentine alteration by seawater led to the formation of authigenic phyllosilicates, causing the highest natural fluid δ30Si values measured to date (up to +5.2 ± 0.2‰). Here we show that seafloor alteration of serpentinites is a source of Si to the ocean with extremely high fluid δ30Si values, which can explain anomalies in the marine Si budget like in the Cascadia Basin and which has to be considered in future investigations of the global marine Si cycle.

A new freshwater shrimp species of the genus Palaemon Weber, 1795 (Decapoda: Caridea: Palaemonidae) from northeastern Japan

Zootaxa ◽  
2019 ◽  
Vol 4576 (2) ◽  
pp. 239 ◽  
Author(s):  
YUICHI KATOGI ◽  
SUSUMU CHIBA ◽  
KATSUHIDE YOKOYAMA ◽  
MAKOTO HATAKEYAMA ◽  
SHIGERU SHIRAI ◽  
...  
Keyword(s):  
New Species ◽  
The Sea Of Japan ◽  
Rrna Gene ◽  
Japanese Species ◽  
Northeastern Japan ◽  
The Pacific ◽  
Pacific Side ◽  
Miyagi Prefecture ◽  
Mitochondrial 16S Rrna Gene ◽  
Hyogo Prefecture

The palaemonid shrimp genus Palaemon Weber 1795 is currently represented by 87 species worldwide, of which 36 species inhabit freshwater environments. In this study, we describe a new species of the genus, P. septemtrionalis, primarily based on material collected from rivers in Miyagi Prefecture, Tohoku District, northeastern Japan. The present new species is morphologically and genetically close to Palaemon paucidens De Haan, 1841, but it is morphologically distinguishable from the latter by the chela of the pereopod 2 being longer than the carpus (versus shorter than the carpus in P. paucidens) and the possession of a low, laminar convexity on the flexor margin of the pereopod 3 dactylus just proximal to the base of the unguis (such a laminar structure is absent in P. paucidens). Comparison of partial sequences of the mitochondrial 16S rRNA gene supports the recognition of the new species. Examination of museum collections and a BLAST search on GenBank revealed that the geographical range of the new species includes the Sea of Japan side ranging from Hokkaido to Hyogo Prefecture and the Pacific side ranging from Aomori to Miyagi Prefecture. An identification key to the 13 Japanese species of the genus is presented. 

Sign in / Sign up

Export Citation Format

Share Document