共查询到20条相似文献，搜索用时 31 毫秒
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Mike Sandiford 《Geophysical Journal International》2008,174(2):659-671
The highest intermediate depth moment release rates in Indonesia occur in the slab beneath the largely submerged segment of the Banda arc in the Banda Sea to the east of Roma, termed the Damar Zone. The most active, western-part of this zone is characterized by downdip extension, with moment release rates (∼1018 Nm yr–1 per 50 km strike length) implying the slab is stretching at ∼10−14 s−1 consistent with near complete slab decoupling across the 100–200 km depth range. Differential vertical stretching along the length of the Damar Zone is consistent with a slab rupture front at ∼100–200 km depth beneath Roma propagating eastwards at ∼100 km Myr–1 . Complexities in the slab deformation field are revealed by a narrow zone of anomalous in-plane P -axis trends beneath Damar, where subhorizontal constriction suggests extreme stress concentrations ∼100 km ahead of the slab rupture front. Such stress concentrations may explain the anomalously deep ocean gateways in this region, in which case ongoing slab rupture may have played a key role in modulating the Indonesian throughflow in the Banda Sea over the last few million years. 相似文献
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The migration of teleseismic receiver functions yields high-resolution images of the crustal structure of western Crete. Data were collected during two field campaigns in 1996 and 1997 by networks of six and 47 short-period three-component seismic stations, respectively. A total of 1288 seismograms from 97 teleseismic events were restituted to true ground displacement within a period range from 0.5 to 7 s. The application of a noise-adaptive deconvolution filter and a new polarization analysis technique helped to overcome problems with local coda and noise conditions. The computation and migration of receiver functions results in images of local crustal structures with unprecedented spatial resolution for this region. The crust under Crete consists of a continental top layer of 15–20 km thickness above a 20–30 km thick subducted fossil accretionary wedge with a characteristic en echelon fault sequence. The downgoing oceanic Moho lies at a depth of 40–60 km and shows a topography or undulation with an amplitude of several kilometres. As a consequence of slab depth and distribution of local seismicity, the Mediterranean Ridge is interpreted as the recent accretionary wedge. 相似文献
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Flexure of subducted slabs 总被引：2，自引：0，他引：2
The subducted lithosphere is regarded as a thin elastic plate that bends as a consequence of slab pull, the pressure of the asthenospheric flow induced by the subduction motion and the pressure exerted by the asthenospheric motion relative to the lithosphere. In westward subductions the latter factor enhances the slab pull, but in eastward subductions it opposes it. As a result, the subduction angle changes continuously with depth, following an elastic profile: it is smaller in eastward subductions and larger in those having a westward direction. The application of the model to 13 subducted slabs shows a good fit between the observed and the calculated shapes of the slabs. 相似文献
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《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(4):291-295
In 1982 a c.5 m2 slab of peat, c.25 cm thick, was discovered on a peat bog on the island of Andøya in northern Norway. The peat slab, which weighed c.1 ton, was found 4 m to 5 m from a hole having precisely the same shape. Investigations on Andøya to date have provided information on six quite similar phenomena with slab weights varying between 100 kg and 4 tons. Outside Andøya, five similar phenomena have been recorded in Norway, and pieces of earth displaced from their original locations have been reported in Britain, Germany and the United States. Lightning is hypothesized to have caused these phenomena. 相似文献
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Slab pull effects from a flexural analysis of the Tonga and Kermadec trenches (Pacific Plate) 总被引：1，自引：0，他引：1
Daniel Garcia-Castellanos Montserrat Torne & Manel Fernàndez 《Geophysical Journal International》2000,141(2):479-484
Thin-plate flexure models have been frequently used to explain the mechanical behaviour of the lithosphere at oceanic trenches, but little attention has been paid to using them as a way to check the relative importance of different plate-driving mechanisms. A 2-D numerical algorithm accounting for the flexural deflection of the lithosphere controlled by multilayered elastic–plastic rheology (brittle–elastic–ductile) has been applied to the seaward side of the Tonga and Kermadec trenches. This approach gives a better fit to the bathymetry on both trenches than assuming classical homogeneous plate models, and allows the interplate coupling forces and the lithospheric strength profile to be constrained. Our results show that, in order to fit the observed deflection of the lithosphere, a regional tensile horizontal force must act in both regions. This tensile force and its flexural effects are discussed in terms of slab pull as a main plate-driving mechanism. The predicted stress and yielding distributions partially match the outer-rise earthquake hypocentres within the subducting plate, and thus do not invalidate the model. 相似文献
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