Stresses along the metastable wedge of olivine in a subducting slab: possible explanation for the Tonga double seismic layer

Guest, A.; Schubert, G.; Gable, Carl W.

doi:10.1016/j.pepi.2003.11.012

Cited by 26 publications

(24 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The values of the resultant stress are summarized in Table 2; the misfit function for data set C is shown in Figure 4. The stress found is consistent with results obtained by other authors [Isacks and Molnar, 1971;Frohlich, 1989;Zhou, 1990b;Guest et al, 2004]. The maximum compression and tension axes are parallel to the subducting slab: The compression axis follows the subduction flow, and the tension axis is mostly horizontal and parallel to the trench.…”

Section: Slab Geometry and Stress In The Slabsupporting

confidence: 91%

Inversion for anisotropy from non‐double‐couple components of moment tensors

Vavryčuk

2004

J. Geophys. Res.

View full text Add to dashboard Cite

[1] An inversion method for retrieving seismic anisotropy from non-double-couple components of seismic moment tensors is presented. The method requires a set of highly accurate moment tensors of earthquakes that occurred in a homogeneous anisotropic focal area on differently oriented faults. In contrast to standard methods retrieving anisotropy from travel times or from shear wave splitting, which yield an overall anisotropy averaged along a whole ray path, the presented method yields a local value of anisotropy just in the focal area. The method is robust, being able to retrieve the orientation as well as strength of anisotropy even for low anisotropy symmetries as for orthorhombic symmetry. The method can utilize the moment tensors constrained to have zero trace, but using unconstrained moment tensors is advantageous. The method is applied to retrieving anisotropy in the Tonga subduction zone using moment tensors of deep-focus earthquakes reported in the Harvard centroid moment tensor catalog. The inversion is complemented by tests on synthetic data to assess its stability and the accuracy of the results. The inversion indicates that the subduction zone is anisotropic with orthorhombic symmetry. The orientation of the intra-slab anisotropy is defined by axes (azimuth/dip) a 1 = 320°/54°, a 2 = 121°/38°, and a 3 = 223°/81°. The errors in the azimuth and dip are about 5°. The first and second axes lie along the downdip motion of the slab and along the normal to the slab, respectively. The strength of the P, S1, and S2 anisotropy is of 7.3 ± 1.5%, 13.4 ± 2.5%, and 12.6 ± 3.5%, respectively. The errors of anisotropy strength are only rough estimates, which reflect random but not systematic errors in the moment tensors used in the inversion. The values for anisotropy strength in the slab are remarkably higher than those observed in the surrounding mantle. The symmetry axes of anisotropy coincide with the principal stress directions in the slab. This manifests a primary impact of stress on anisotropy formation. The retrieved anisotropy in the slab can serve as an additional constraint on its structure and mineralogical composition.

show abstract

Section: Slab Geometry and Stress In The Slabsupporting

confidence: 91%

Inversion for anisotropy from non‐double‐couple components of moment tensors

Vavryčuk

2004

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

“…Kaneshima et al (2007) adopted adiabatic shear instability to explain the deep seismicity in the subducted Mariana slab in which deep earthquakes occur around one side of the MOW but no earthquake occurs on the other side. The transformational faulting hypothesis is advocated by many researchers based on mineral physics experiments (Kirby et al, 1991;Green and Houston, 1995), numerical modeling (Guest et al, 2004), and seismological investigations (Wiens et al, 1993;Frohlich, 1994;Green and Houston, 1995;Kirby et al, 1996;Green, 2003). According to this hypothesis, a deep earthquake is caused by failures, and in the MOW positive buoyancy is generated by the relatively low-velocity and low-density wedge (Kirby et al, 1996;Bina et al, 2001), which is opposite to the downward thermal buoyancy forces.…”

Section: Discussionmentioning

confidence: 99%

“…A lower seismic-velocity anomaly in MOW was detected by fitting travel-time residuals of deep earthquakes (Iidaka and Suetsugu, 1992;Jiang et al, 2008a) and by modeling waveforms of deep earthquakes (e.g., Koper and Wiens, 2000;Kaneshima et al, 2007). The density anomaly and stress distribution within the MOW were estimated by numerical modeling studies (e.g., Vacher et al, 1999;Bina et al, 2001;Guest et al, 2004). All these previous studies suggest that not only seismic velocity but also density inside the MOW are lower than that in the surrounding mantle.…”

Section: Introductionmentioning

confidence: 98%

Metastable olivine wedge in the subducting Pacific slab and its relation to deep earthquakes

Jiang

Zhao

2011

Journal of Asian Earth Sciences

View full text Add to dashboard Cite

“…Iidaka and Furukawa (1994) detected two planes about 25 km apart in the Izu Bonin subduction zone using S-P converted phases at the upper boundary of the slab. A comparison of the modeled stresses due to a metastable wedge to the characteristics of the deep double zone in Tonga suggested that the lower seismic zone may reside well below a hypothesized metastable wedge, which would imply the operation of two mechanisms of rupture (Guest et al, 2004). The upper layer lies 15-20 km below the top surface of the slab.…”

Section: Double Seismic Zonesmentioning

confidence: 99%

Deep Earthquakes

Houston

2015

Treatise on Geophysics

View full text Add to dashboard Cite

Stresses along the metastable wedge of olivine in a subducting slab: possible explanation for the Tonga double seismic layer

Cited by 26 publications

References 52 publications

Inversion for anisotropy from non‐double‐couple components of moment tensors

Inversion for anisotropy from non‐double‐couple components of moment tensors

Metastable olivine wedge in the subducting Pacific slab and its relation to deep earthquakes

Deep Earthquakes

Contact Info

Product

Resources

About