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Sea Plate (sea + plate)

Distribution by Scientific Domains
Earth and Environmental Science75%

Kinds of Sea Plate

  • philippine sea plate
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    Selected Abstracts

    Data construction method for the analysis of the spatial distribution of disastrous earthquakes in Taiwan

    INTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 2 2009
    Hsiao-Fan Wang
    Abstract Considering a disastrous earthquake as a rare event, the aim of this study is to apply the proposed data construction method (DCM) to determine the possible distribution pattern of disastrous earthquakes in Taiwan. Owing to the availability of only a limited amount of data and based on the multiset division of DCM, virtual samples have been generated. The procedure is illustrated by a numerical experiment that consists of data from 12 disastrous earthquakes in Taiwan from 1990 to 1999. The results show that the pattern constructed by DCM is geologically consistent with the actual phenomenon, which was caused by the collision of the Philippine Sea Plate and the Eurasian Continental Plate. A case study of disastrous earthquakes in East Taiwan is then conducted by studying three near-source regions. Based on the Kolmogorov,Smirnov test, the constructed spatial distribution has shown its validity and capability in providing useful information for the risk assessment of disastrous earthquakes as rare events. [source]

    Fault configuration produced by initial arc rifting in the Parece Vela Basin as deduced from seismic reflection data

    ISLAND ARC, Issue 3 2007
    Mikiya Yamashita
    Abstract The Parece Vela Basin (PVB), which is a currently inactive back-arc basin of the Philippine Sea Plate, was formed by separation between the Izu-Ogasawara Arc (IOA) and the Kyushu-Palau Ridge (KPR). Elucidating the marks of the past back-arc opening and rifting is important for investigation of its crustal structure. To image its fault configurations and crustal deformation, pre-stack depth migration to multichannel seismic reflection was applied and data obtained by the Japan Agency for Marine-Earth Science and Technology and Metal Mining Agency of Japan and Japan National Oil Corporation (Japan Oil, Gas and Metals National Corporation). Salient results for the pre-stack depth-migrated sections are: (i) deep reflectors exist around the eastern margin of KPR and at the western margin of IOA down to 8 km depth; and (ii) normal fault zones distributed at the eastern margin of the KPR (Fault zone A) and the western margin of the IOA (Fault zone B) have a total displacement of greater than 500 m associated with synrift sediments. Additional normal faults (Fault zone C) exist 20 km east of the Fault zone B. They are covered with sediment, which indicates deposition of recent volcanic products in the IOA. According to those results: (i) the fault displacement of more than 500 m with respect to initial rifting was approximately asymmetric at 25 Ma based on PSDM profiles; and (ii) the faults had reactivated after 23 Ma, based on the age of deformed sediments obtained from past ocean drillings. The age of the base sediments corresponds to those of spreading and rotation after rifting in the PVB. Fault zone C is covered with thick and not deformed volcanogenic sediments from the IOA, which suggests that the fault is inactive. [source]

    Tectonic accretion of a subducted intraoceanic remnant arc in Cretaceous Hokkaido, Japan, and implications for evolution of the Pacific northwest

    ISLAND ARC, Issue 4 2005
    Hayato Ueda
    Abstract An accretionary complex, which contains fragments of a remnant island arc, was newly recognized in the Cretaceous accretionary terranes in Hokkaido, Japan. It consists of volcanics, volcanic conglomerate, intermediate to ultramafic intrusive rocks with island-arc affinity including boninitic rocks, accompanied by chert and deformed terrigenous turbidites. Compared with the results of modern oceanic surveys, the preserved sequence from island-arc volcanics to chert, via reworked volcanics, is indicative of intraoceanic remnant arc, because the sequence suggests an inactive arc isolated within a pelagic environment before its accretion. The age of a subducting oceanic crust can be discontinuous before and after a remnant-arc subduction, resulting in abrupt changes in accretion style and metamorphism, as seen in Cretaceous Hokkaido. Subduction of such an intraoceanic remnant arc suggests that the subducted oceanic plate in the Cretaceous was not an extensive oceanic plate like the Izanagi and/or Kula Plates as previously believed by many authors, but a marginal basin plate having an arc,back-arc system like the present-day Philippine Sea Plate. [source]

    A preliminary study of crustal structure in Taiwan region using receiver function analysis

    GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2004
    Kwang-Hee Kim
    SUMMARY Selected teleseismic data observed at temporary and permanent broad-band stations have been analysed using the receiver function method in order to investigate the very complex crustal structure in Taiwan region. Very significant azimuthal variations of radial and transverse receiver function responses from broad-band stations could be attributed to, among other things, the sampling of incoming seismic waves across the nearby subduction zone, a subsurface dipping interface, or a localized anisotropic region. A mid-crust discontinuity, interpreted as the Conrad discontinuity, can be identified at 18,20 km depth beneath TATO and TPUB stations in the Western Foothills, but is absent beneath the two nearby stations SSLB and TDCB in the Central Mountain Range. The separation of upper and lower crust beneath the Western Foothills and the steady increase in crustal velocity as a function of depth across the entire thicker crust beneath the Central Mountain Range suggest that the tectonic evolution of the crust may be significantly different for these two adjacent regions. Although a ,thin-skinned' model may be associated with the tectonic evolution of the upper crust of the Western Foothills and Western Coastal Plain, a ,thick-skinned' or ,lithospheric deformation' model can probably be applied to explain the crustal evolution of the Central Mountain Range. A trend of crustal thinning from east (50,52 km) to west (28,32 km) is in very good agreement with the results from two east,west-trending deep seismic profiles obtained using airgun sources. The thinner crust (20,30 km) beneath TWB1 station in northeastern Taiwan can be associated with the high-heat-flow backarc opening at the western terminus of the Okinawa trough behind the subduction of the Philippine Sea plate. The relatively simple crustal structure beneath KMNB station, offshore southeastern China, depicts typical continental crust, with the Moho depth at 28,32 km. An apparent offset of the thickest Moho beneath NACB station from the topographic high in the central Central Mountain Range suggests that the Taiwan orogeny has probably not reached its isostatic status. [source]