scholarly journals Relative Plate Motion between the Eurasian Plate and the Pacific Plate at the Japan Trench

1980 ◽  
Vol 33 (1) ◽  
pp. 95-97
Author(s):  
Takao EGUCHI
Keyword(s):  
Pacific Plate ◽  
Plate Motion ◽  
Japan Trench ◽  
Eurasian Plate ◽  
The Pacific ◽  
Relative Plate Motion

scholarly journals First measurement of the displacement rate of the Pacific Plate near the Japan Trench after the 2011 Tohoku-Oki earthquake using GPS/acoustic technique

2015 ◽  
Vol 42 (20) ◽  
pp. 8391-8397 ◽  
Author(s):  
Fumiaki Tomita ◽  
Motoyuki Kido ◽  
Yukihito Osada ◽  
Ryota Hino ◽  
Yusaku Ohta ◽  
...  
Keyword(s):  
Pacific Plate ◽  
Japan Trench ◽  
Displacement Rate ◽  
Acoustic Technique ◽  
The Pacific

scholarly journals Geochemical Characterization of Intraplate Magmatism from Quaternary Alkaline Volcanic Rocks on Jeju Island, South Korea

2021 ◽  
Vol 11 (15) ◽  
pp. 7030
Author(s):  
Cheolhong Kim ◽  
Naing Aung Khant ◽  
Yongmun Jeon ◽  
Heejung Kim ◽  
Chungwan Lim
Keyword(s):  
Fractional Crystallization ◽  
Upper Mantle ◽  
Volcanic Rocks ◽  
Pacific Plate ◽  
Mantle Xenoliths ◽  
Jeju Island ◽  
Eurasian Plate ◽  
Intraplate Magmatism ◽  
The Pacific ◽  
Host Basalt

The major and trace elements of Quaternary alkaline volcanic rocks on Jeju Island were analyzed to determine their origin and formation mechanism. The samples included tephrite, trachybasalts, basaltic trachyandesites, tephriphonolites, trachytes, and mantle xenoliths in the host basalt. Although the samples exhibited diversity in SiO2 contents, the relations of Zr vs. Nb and La vs. Nb indicated that the rocks were formed from the fractional crystallization of a single parent magma with slight continental crustal contamination (r: 0–0.3 by AFC modeling), rather than by the mixing of different magma sources. The volcanic rocks had an enriched-mantle-2-like ocean island basalt signature and the basalt was formed by partial melting of the upper mantle, represented by the xenolith samples of our study. The upper mantle of Jeju was affected by arc magmatism, associated with the subduction of the Pacific Plate beneath the Eurasian Plate. Therefore, we inferred that two separate magmatic events occurred on Jeju Island: one associated with the subduction of the Pacific Plate beneath the Eurasian Plate (represented by xenoliths), and another associated with a divergent setting when intraplate magmatism occurred (represented by the host rocks). With AFC modeling, it can be proposed that the Jeju volcanic rocks were formed by the fractional crystallization of the upper mantle combined with assimilation of the continental crust. The xenoliths in this study had different geochemical patterns from previously reported xenoliths, warranting further investigations.

scholarly journals The Mode of Trench-Parallel Subduction of the Middle Ocean Ridge

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaobing Shen ◽  
Wei Leng
Keyword(s):  
Evolutionary Process ◽  
Pacific Plate ◽  
North American Plate ◽  
Plate Motion ◽  
Western Boundary ◽  
Ridge Subduction ◽  
Ocean Ridges ◽  
The Pacific ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

Trench-parallel subduction of mid-ocean ridges occurs frequently in plate motion history, such as along the western boundary of the Pacific plate in the early Cenozoic and along the eastern boundary of the Pacific plate at present. Such subduction may strongly alter the surface topography, volcanic activity and slab morphology in the mantle, whereas few studies have been conducted to investigate its evolutionary process. Here, we construct a 2-D viscoelastoplastic numerical model to study the modes and key parameters controlling trench-parallel subduction of mid-ocean ridges. Our model results show that the subduction modes of mid-ocean ridges can be primarily categorized into three types: the fast spreading mode, the slow spreading mode, and the extinction mode. The key factor controlling these subduction modes is the relative motion between the foregoing and the following oceanic plates, which are separated by the mid-ocean ridge. Different subduction modes exert different surface geological expressions, which may explain specific evolutionary processes related to mid-ocean ridge subduction, such as topographic deformation and the eruption gap of volcanic rocks in East Asia within 55–45 Ma and in the western North American plate during the late Cenozoic.

scholarly journals The Wandel Hav Strike-Slip Mobile Belt – A Mesozoic plate boundary in North Greenland

2001 ◽  
Vol 48 ◽  
pp. 149-158
Author(s):  
E. Håkansson ◽  
S.A.S. Pedersen
Keyword(s):  
Plate Boundary ◽  
Strike Slip ◽  
Seafloor Spreading ◽  
Plate Motion ◽  
Mobile Belt ◽  
Eurasian Plate ◽  
Late Palaeozoic ◽  
Break Up ◽  
Relative Plate Motion ◽  
North Greenland

The historical ‘de Geer Line’ between Svalbard and Greenland is shown to have had a Mesozoic precursor now residing well within the continental Greenland plate, where it coincides with the Wandel Hav Strike-Slip Mobile Belt. Well-constrained phases in relative plate motion reflected in the mobile belt are discernible back to the mid Jurassic, with more obscure phases dating even further back. There is evidence that the Wandel Hav Strike-Slip Mobile Belt may have been formed already in Late Palaeozoic time during onset of Pangean break-up; evidence for strike-slip movements of this age is, however, largely circumstantial, due to severe overprinting during the later phases. Wrench tectonics along the ‘fossil’ plate boundary culminated around the Cretaceous – Palaeogene boundary in the major right-lateral, transpressional Kronprins Christian Land Orogeny. Thus, the Wandel Hav Strike-Slip Mobile Belt may constitute the geological/structural expression of the Mesozoic Laurentian – Eurasian plate boundary all the way up to initiation of actual seafloor spreading at chron 24 in Palaeogene time.

scholarly journals Focal Mechanisms of Small Earthquakes within the Pacific Plate near the Japan Trench

2012 ◽  
Vol 64 (2) ◽  
pp. 75-90 ◽  
Author(s):  
Shoko KOGA ◽  
Yoshihiro ITO ◽  
Ryota HINO ◽  
Masanao SHINOHARA ◽  
Norihito UMINO
Keyword(s):  
Pacific Plate ◽  
Focal Mechanisms ◽  
Japan Trench ◽  
The Pacific

scholarly journals Pemakaian Bracing Pada Bangunan Tahan Gempa dengan Analisis Pushover (The Usage of Bracing on Earthquake Resistant Buildings with Pushover Analysis)

2016 ◽  
Vol 1 (01) ◽  
pp. 84
Author(s):  
Dwi Wahyu Anggraeni ◽  
Erno Widayanto ◽  
Dwi Nurtanto
Keyword(s):  
Collision Energy ◽  
Pushover Analysis ◽  
Pacific Plate ◽  
Earthquake Response ◽  
Eurasian Plate ◽  
High Rise ◽  
Australian Plate ◽  
The Pacific ◽  
Earthquake Resistant ◽  
The Difference

AbstractMost of Indonesia area is an earthquake- prone region. This is caused by the confluence of three major plates world that are subduction. Indo-Australian Plate colliding with the Eurasian plate off the coast of Sumatra, Java and Nusa Tenggara, while the Pacific plate in northern Guinea and North Maluku. In the vicinity of the meeting location this plate collision energy accumulated in the form of earthquake. The quake destroyed much of the multi-storey buildings that do not have adequate strength. Therefore , the higher the building, the greater the effects of the earthquake were received by the building. One way to acquire resistance to earthquake response was to add rigidity to a building. How to obtain the stiffness of a building is to install bracing for high-rise buildings. The purpose of this analysis was conducted to determine usage behavior particularly bracing displacement. The Results of this analysis showed a reduction in horizontal deviation of the building due to the addition of frame bracing. The difference in the percentage of horizontal deviation without bresing building and building using bresing X is 82.519%. While the difference in the percentage of horizontal deviation without order bresing building and building using bresing V is 64.904%.Keywords: pushover analysis , bracing, displacement,earthquake AbstrakSebagian besar wilayah Indonesia merupakan wilayah rawan gempa. Hal ini disebabkan oleh pertemuan tiga lempeng utama dunia yang bersifat subdaksi. Lempeng Indo- Australia bertabrakan dengan lempeng Eurasia di lepas pantai Sumatra, Jawa dan Nusa Tenggara, sedangkan lempeng Pasific di utara Irian dan Maluku Utara. Di sekitar lokasi pertemuan lempeng ini akumulasi energi tabrakan terkumpul sehingga lepas berupa gempa bumi. Gempa banyak menghancurkan bangunan- bangunan bertingkat yang tidak mempunyai kekuatan yang memadai. Oleh karena itu, semakin tinggi bangunan maka semakin besar pula efek gempa yang diterima oleh bangunan tersebut. Salah satu cara untuk memperoleh ketahanan terhadap respon gempa adalah menambah kekakuan pada suatu bangunan. Cara memperoleh kekakuan suatu bangunan adalah dengan memasang pengekang (bracing) untuk bangunan tinggi. Tujuan dari analisa ini dilakukan untuk mengetahui perilaku pemakaian bracing khususnya displacement. Hasil dari analisa ini menunjukkan terjadinya pengurangan simpangan horizontal gedung karena adanya penambahan rangka bracing. Selisih presentase simpangan horizontal gedung tanpa bresing dan gedung dengan menggunakan bresing X adalah 82,519%. Sedangkan selisih presentase simpangan horizontal gedung tanpa rangka bresing dan gedung dengan menggunakan bresing V adalah 64,904%.Kata kunci: analisa pushover , bracing, displacement, gempa

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