Although plate tectonics is well established, how a new subduction zone initiates remains controversial. Based on plate reconstruction and recent ocean drilling within the Izu-Bonin-Mariana, we advance a new geodynamic model of subduction initiation (SI). We argue that the close juxtaposition of the nascent plate boundary with relic oceanic arcs is a key factor localizing initiation of this new...

We show that a new subduction zone can initiate at a preexisting dipping fault zone with reasonable plate forces, consistent with what is observed in the western Pacific. The dynamics of subduction initiation within a viscoelastic medium has been systematically explored with the finite element method. We investigate the compression of oceanic lithosphere with hoth force and velocity boundary co...

High attenuation of short-period body waves and extremely low surface-wave group velocities have been found for seismic paths that traverse the crust and upper mantle beneath the concave side of the Lesser Antilles island arc (eastern Caribbean). The observations can be explained in terms of the currently accepted models of lithospheric plate subduction at other island arcs such as Fiji-Tonga, ...

Subduction initiation is a critical link in the plate tectonic cycle. Intraoceanic subduction zones can form along transform faults and fracture zones, but how subduction nucleates parallel to mid-ocean ridges, as in e.g., the Neotethys Ocean during the Jurassic, remains a matter of debate. In recent years, extensional detachment faults have been widely documented adjacent to slow-spreading and...

Subduction of oceanic lithosphere occurs through two modes: subducting plate motion and trench migration. Using a global subduction zone data set and three-dimensional numerical subduction models, we show that slab width (W) controls these modes and the partitioning of subduction between them. Subducting plate velocity scales with W(2/3), whereas trench velocity scales with 1/W. These findings ...

[1] To investigate the possible physical mechanisms of recently observed aseismic slip events in the Cascadia, Japan and Mexico subduction zones, we apply a Dieterich-Ruina rate and state friction law to a three dimensional model of a shallow subduction fault. That is loaded by imposed steady plate slip rate far downdip along the thrust interface. Friction properties are temperature and hence d...

the makran subduction zone in southeastern iran and southern pakistan is where the oceanic crust of the arabian plate (oman sea) is subducting beneath eurasia. compared to other subduction zones in the world, the makran subduction zone has some unusual features, including different seismicity patterns in its eastern and western parts. also, the quaternary volcanoes in the eastern part of makran...

Recent observations of an association between forearc basins and slip during subduction thrust earthquakes suggest a link between processes controlling upper plate structure and seismic coupling on the subduction-zone thrust fault. We present a mechanism for the formation of these basins where sedimentation occurs on landward-dipping segments of the subduction wedge, which itself is actively gr...

Geophysical data from the offshore Cascadia forearc reveal many Quaternary upper-plate faults and folds. Most active structures are within the accretionary wedge, but significant deformation is also found on the continental shelf. Several faults and synclines project into adjacent coastal bays where deformation of Pleistocene marine terraces is reported. Rapidly buried marsh deposits and drowne...

baft ophiolitic – mélange belt is a part of the ophiolite melange belt of central iran whose genesis is considered as an environment related to tethys subduction at upper cretaceous. major part of intrusive masses of baft ophiolitic – melange form gabbros with the inequigranular texture fine to coarse and pegmatitic, plagiogranites also with inequigranular general texture have been developed wi...