Results 1 to 10 of about 3,274 (216)

Shear-wave anisotropy beneath the Ryukyu arc [PDF]

Earth, Planets and Space, 2009
Abstract We have investigated regional shear-wave splitting beneath the Ryukyu arc in order to clarify the mantle flow beneath the Ryukyu arc and compare it with the extension of the Okinawa Trough. The splitting of regional shear waves (direct S) in the central and southern Ryukyu arc regions was analyzed in terms of fast-polarization ...
Mamoru Nakamura, Ai Yamamoto
core   +5 more sources

Large-scale slope failure and active erosion occurring in the southwest Ryukyu fore-arc area [PDF]

Natural Hazards and Earth System Sciences, 2001
The southwestern Ryukyu area east of Taiwan Island is an arcuate boundary between Philippine Sea Plate and Eurasian Plate. The topographic features in the area are characterised by (1) a large-scale amphitheatre off Ishigaki Island, just on the ...
T. Matsumoto, M. Kimura, M. Nakamura, T. Ono   +3 more
doaj   +5 more sources

Seismic evidence for arc segmentation, active magmatic intrusions and syn-rift fault system in the northern Ryukyu volcanic arc [PDF]

Earth, Planets and Space, 2018
Tectonic and volcanic structures of the northern Ryukyu arc are investigated on the basis of multichannel seismic (MCS) reflection data. The study area forms an active volcanic front in parallel to the non-volcanic island chain in the eastern margin of ...
Ryuta Arai, Shuichi Kodaira, Tsutomu Takahashi, Seiichi Miura, Yoshiyuki Kaneda   +4 more
doaj   +3 more sources

Middle Miocene forearc alkaline magmatism in Amami-Oshima Island, central Ryukyu Arc: implications for paleoreconstruction of Shikoku Basin [PDF]

Earth, Planets and Space, 2023
During the middle Miocene, forearc alkaline magmatism occurred in the Outer Zone of Southwest Japan and the northern Ryukyu Arc, resulting in the formation of forearc alkaline basaltic rocks with ocean island basalt (OIB)-like chemical signatures.
Ginta Motohashi, Osamu Ishizuka, Hirokuni Oda, Takashi Sano, Shun Sekimoto, Kohtaro Ujiie   +5 more
doaj   +2 more sources

TECTONICS OF THE RYUKYU ISLAND ARC

Journal of Physics of the Earth, 1978
The geological and structural contrast between the north and central Ryukyus and the south Ryukyus has been significant since the Late Mesozoic. The difference seems to correspond to that of the nature of the Philippine Sea floor facing the Ryukyus, i.e. the Daito Ridges and Amami plateau to the north and deeper basin to the south.
Koshiro Kizaki
openalex   +3 more sources

Stress-driven faulting with weak overpressure in the Tokara Islands, Ryukyu Arc: implications for fault reactivation under backarc extension

Earth, Planets and Space
We investigate the shallow stress regime and pore fluid pressure conditions in the Tokara Islands region of the northern Ryukyu Arc, where active seismicity occurs in a complex tectonic setting characterized by backarc extension.
Makoto Otsubo, Yuta Amezawa
doaj   +3 more sources

Effects of a Whole Plant Extract of Scutellaria rubropunctata var. rubropunctata on Bone Metabolism with Estrogen Receptor Activation [PDF]

Plants, 2022
We screened natural resources for estrogen receptor (ER)-activating and bone metabolism-promoting activities with the aim of finding potential treatments for osteoporosis. A screen of 1531 extracts from Ryukyu Arc plants using a luciferase reporter assay
Misaki Watanabe, Tadahiro Yahagi, Takahiro Shirayama, Katsunori Miyake, Hitoshi Kotani, Takuya Ogawa, Keiichi Matsuzaki   +6 more
doaj   +2 more sources

Upper mantle velocity structure in the Ryukyu and Taiwan-Luzon arcs.

Journal of Physics of the Earth, 1984
Upper mantle velocity structure in the Ryukyu and Taiwan-Luzon Island arc regions of the northwest Pacific has been determined to a depth of about 255 km from the analysis of P and S wave travel times data of 106 earthquakes with focal depths varying from 35 to 255 km.
V. G. Krishna, K. L. Kaila
openalex   +3 more sources

K-Ar dating of the volcanic rocks in the Ryukyu arc.

JOURNAL OF MINERALOGY, PETROLOGY AND ECONOMIC GEOLOGY, 1991
High magnesian andesites from Kume-jima and Iriomote-jima, the Ryukyu islands were dated by the K-Ar method with the basalts from Kobi-sho and Sekibi-sho, the Senkaku islands. The obtained K-Ar ages of the high magnesian andesites are 6.08 ± 0.46 Ma and 13.1 ± 1.1 Ma for the sample (s) from Kume-jima and Iriomote-jima, respectively.
Ryuichi Shinjo, Masao Ban, Kazuo Saito, Yuzo Kato   +3 more
openalex   +3 more sources

Formation Age of the Ryukyu Arc-Okinawa Trough System.

Journal of Geography (Chigaku Zasshi), 1991
The Ryukyu Arc-Okinawa Trough system is one of several arc-backarc systems alongthe margin of the western Pacific and east Asia. Recent results of seismic refractionand reflection studies have revealed that the origin of the trough is the continental rifting, and the trough is in a state of the active rifting stage (e. g.
M. Furukawa
openalex   +3 more sources