Source-side shear-wave splitting and upper-mantle flow beneath the Arakan slab, India-Asia-Sundalind triple junction

Lithospheric Structure of Eastern Tibetan Plateau from Terrestrial and Satellite Gravity Data Modeling: Implication for Asthenospheric Underplating

“…East of the eastern Tibetan plateau, the geometry of the collision zone changes dramatically, as the Indian plate is subducting eastward and sinks into the mantle transition zone along the Burmese arc (Figure 1; [13, 147]), which is very different from the main Himalayan-Tibetan collision zone. Hence, on a large scale, this transition may be explained by eastward subduction and westward trench retreat of the Burmese arc during clockwise rotation of the Sunda block (e.g., [13,53]). On a local scale, Chen et al [50] suggest that the physical properties of colliding Indian lithosphere are far from homogeneous causing kinematic differences within the plate (e.g., a change in slab dip from west to east), while Shi et al [49] try to explain it through eclogitization of the lower Indian crust, acting as a hinge for slab roll-back, hence a steeper slab angle.…”

“…Recent tomographic studies indicate that slab dip becomes steeper from west to east (~8°to~20°, [49]). The mechanism of deformation changes from underthrusting/flat slab in the west to slab roll-back/steeper slab in the east, which may have been caused by eastward subduction and westward retreat of the Burmese arc during clockwise rotation of the Sunda block ( Figure 1; [13,53]). A numerical model from Li et al [54] also suggests a causal relationship between a steeper slab angle and the removal of lithospheric mantle in the eastern Tibetan plateau.…”

Anisotropy in subduction zones: Insights from new source side S wave splitting measurements from India

“…Estimation of the strength of anisotropy beneath the source necessitates suppressing the effect on the receiver side, which may not be straightforward if the receiver side has complex (e.g., two layered) anisotropy [e.g., Russo , , ; Russo et al , ; Lynner and Long , , ; Eakin and Long , ]. Due to this constraint, only those stations which show simple anisotropy that is well characterized can be used [e.g., Russo , , ; Russo et al , ; Lynner and Long , , ; Eakin and Long , ]. To estimate the contribution from the source side, the shear wave splitting parameters obtained from the core refracted (like S K ( K ) S and P K S ) phases are used to correct anisotropy at the receiver side.…”

“…However, most of the inferences of trench‐parallel mantle flow also come from S K S splitting measurements [e.g., Polet et al , ; Anderson et al , ; Rabble et al , ; Russo and Silver , ; Smith et al , ; Hoernle et al , ; Pinero‐Feliciangeli and Kendall , ]. In the recent years, efforts are made to understand subslab anisotropy using source side splitting studies [e.g., Russo and Silver , ; Muller et al , ; Russo , , ; Russo and Mocanu , ; Russo et al , ; Foley and Long , ; Di Leo et al , ; Lynner and Long , , , ]. Such studies gained prominence to decipher deformation of the dynamic and complex subslab mantle beneath subduction zones, mainly using stations on the updip side of the slab, since the time spent by the rays in the slab is minimal.…”

Chapter 2 Active tectonics of Myanmar and the Andaman Sea

“…If these depths are correct, it would suggest that this region is relatively strong, and would explain why it has remained relatively low, potentially able to transfer large stresses as a relatively rigid body. Russo (2012) interpreted the locations obtained by Stork et al (2008) as revealing a number of vertical tears through the slab. This interpretation most likely arises from the relatively small number of events studied by Stork et al (2008).…”