Stress in the Indo-Australian plate

Cloetingh, S.A.P.L.; Wortel, Rinus

doi:10.1016/0040-1951(86)90024-7

Cited by 317 publications

(179 citation statements)

References 56 publications

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“…The compressive stresses deduced from earthquake focal mechanism studies (Stein and Okal, 1978;Bergman and Solomon, 1985) and derived from plate boundary forces (Cloetingh and Wortel, 1986) would give a far simpler tectonic fabric than that actually observed. The lack of continuity of 226 .I M. NLI.1 the undulations across the fracture zones, the orientation of the axes of the undulations, the strong oblique NE or ENE and NW basement trends, and the earthquake source mechanisms suggest that the fracture zone fabric has substantially modified the stress regime.…”

Section: Discussionmentioning

confidence: 94%

Structural style of intra-plate deformation, Central Indian Ocean Basin: evidence for the role of fracture zones

Bull

1990

Tectonophysics

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The structural style of the intraplate defo~ation developed in the Central Indian Ocean Basin was investigated in an area (7S" E-82* E, 0aS4i0S) to the west of the Afanasy Nikitin seamount using an integrated data set of seismic reflection profiles from Edinburgh University and Lamont-Doherty Geological Observatory. The study area contains two fracture zones, which strike -OOS* E to 010 o E, with oceanic lithosphere (age range -65-78 Ma B.P.) younging westwards across them. No evidence for recent fault activity in the oceanic basement along the fracture zones could be detected in this area, although the close association between intraplate earthquakes and fracture zones elsewhere suggests reactivation of the fracture zones at upper mantle depths in a left lateral strike-slip sense. A statistical study was carried out into the fist and second orders of deformation, long wavelength basement undulations and high-angle reverse faults respectively, and the relationships between them. The orientations of the axes of the undulations vary from 065 o E to 085 'E while the high-angle faults strike consistently at 090' E to 100' E. The results of this analysis suggest that the high-angle faults are the result of the reactivation of two sets of pre-existing spreading-centre normal faults, one set originally facing towards the spreading centre and the other facing away. Furthermore, although the long wavelength undulations are not fault generated, the high-angIe faults have modified the basement topography causing the a~ntuation of some of the basement highs. The observation that the undulations are not fault-generated is consistent with them being of flexural origin (including buckling of the crust and/or lithosphere).Basement undulations are clearly discontinuous across fracture zones and the facing direction of faulting is also offset. This discontinuity, the orientation of the axes of the undulations, the presence of other strong oblique basement trends, and information from regional earthquake studies suggest that the deformation resulted from not only -N-S compression as a result of the continental collision between India and Asia, but also left lateral strike-slip along fracture zones caused by the difference in resistance to plate motion between the continental collision to the north and subduction at the Sunda Arc to the northeast.

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Section: Discussionmentioning

confidence: 94%

Structural style of intra-plate deformation, Central Indian Ocean Basin: evidence for the role of fracture zones

Bull

1990

Tectonophysics

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“…These predictions demonstrate the relative contribution of the various tectonic forces acting on the plate. As was found in a previous study for continental Australia To facilitate a comparison of the predicted stresses discussed above and previous modeling studies, the criteria used to evaluate the models above were applied to the model presented by Cloetingh and Wortel [1986], and the results are included in Table 3. In general, the degree of fit for the predicted stresses of models 3 and 4 are quite similar to those of Cloetingh and Wortel [1986].…”

Section: Discussionmentioning

confidence: 99%

Topography, boundary forces, and the Indo‐Australian intraplate stress field

Coblentz¹,

Zhou²,

Hillis³

et al. 1998

J. Geophys. Res.

151

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Abstract. The relative contribution of topographic (e.g., ridge push, continental margins, and elevated continental crust) and plate boundary (e.g., subduction and collisional) forces to the intraplate stress field in the Indo-Australian plate (IAP) is evaluated through a finite element analysis. Two important aspects of the IAP intraplate stress field are highlighted in the present study: (1) if substantial focusing of the ridge push torque occurs along the collisional boundaries (i.e., Himalaya, New Guinea, and New Zealand), many of the first-order features of the observed stress field can be explained without appealing to either subduction or basal drag forces; and (2) it is possible to fit the observed SHm•,, (maximum horizontal stress orientation) and stress regime information with a set of boundary conditions that results in low tectonic stress magnitudes (e.g., tens of megapascals, averaged over the thickness of the lithosphere) throughout the plate. This study therefore presents a plausible alternative to previous studies of the IAP intraplate stress field, which predicted very large tectonic stress magnitudes (hundreds of megapascals) in some parts of the plate. In addition, topographic forces due to continental margins and elevated continental material were found to play an important role in the predicted stress fields of continental India and Australia, and the inclusion of these forces in the modeling produced a significant improvement in the fit of the predicted intraplate stresses to the available observed stress information in these continental regions. A central focus of this study is the relative importance of the boundary conditions used to represent forces acting along the northern plate margin. We note that a wide range of boundary conditions can be configured to match the large portion of the observed intraplate stress field, and this nonuniqueness continues to make modeling the IAP stress field problematic. While our study is an important step forward in understanding the sources of the IAP intraplate stress field, a more complete understanding awaits a better understanding of the relative magnitude of the boundary forces acting along the northern plate margin.

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“…Numerical stress models have been developed for various plates, such as the Nazca plate [Richardson and Cox, 1984], the Indo-Austmlia plate [Cloetingh and Wortel, 1986], the North America plate [Richardson and Reding, 1991], the South America plate [Stefanick and Jurdy, 1992], and the western region of the Eurasia plate [Grunthal and $tromeyer, 1992]. These model studies generally conclude that ridge push, referred to as ridge slide in this paper, and forces at the base of the lithosphere or subduction zones resisting plate motion play dominant roles in affecting intraplate stress patterns.…”

Section: Introductionmentioning

confidence: 99%