Shangqin Hao

Shangqin Hao

he/him

Seismologist, Mineral physicist

Research

Substantial global radial variations of basalt content near the 660-km discontinuity

Updated:

  • Constrained seismic velocity, density, and basalt content at and below the 660-km discontinuity (d660) by S660S waveform inversions
  • Found that slabs exhibit a smaller impedance jump across the d660 but a steeper gradient below the d660 compared to other regions
  • Suggested that basalt accumulates at the d660, especially in subduction zones, but decreases significantly below it, forming a harzburgite-enriched layer

Upper-mantle structure beneath Alaska imaged by teleseismic S-wave reverberations

Updated:

  • Imaged the Moho and mantle transition zone (MTZ) discontinuities beneath Alaska by stacking long-period teleseismic SH waves
  • Observed crustal thickness is generally consistent with surface topography and gravity measurements
  • Suggested that the Pacific slab may have penetrated into the upper MTZ under central Alaska but not under the Alaska Peninsula

Compositional and thermal state of the lower mantle from joint 3D inversion with seismic tomography and mineral elasticity

Updated:

  • Inverted for the 3D chemical composition and thermal state of the lower mantle based on seismic tomography and mineral elasticity data
  • Found that velocity heterogeneities in the upper lower mantle mainly result from thermal anomalies, whereas those in the lowermost mantle mainly result from compositional or phase variations
  • Found that LLSVPs have ∼500 K higher temperature, higher bridgmanite and iron content than the ambient mantle, supporting the origin from an ancient basal magma ocean

Thermoelasticity of phase D and implications for low-velocity anomalies and local discontinuities at the uppermost lower mantle

Updated:

  • Obtained elasticity and density of phase D under the lower-mantle conditions
  • Proved that the accumulation of phase D may account for seismic anisotropy rather than low-velocity anomalies in the uppermost lower mantle (ULM)
  • Suggested that the decomposition of phase D in the ULM causes a density jump, possibly explaining some discontinuities in subduction zones

Elasticity of akimotoite under the mantle conditions: Implications for multiple discontinuities and seismic anisotropies at the depth of ∼600–750 km in subduction zones

Updated:

  • Calculated the elasticity of akimotoite under the mantle conditions using first-principles calculations
  • Estimated the VP, VS, and density contrasts caused by the akimotoite-related transitions
  • Proved that the discontinuity at the depth of ∼700-750 km in cold slabs could result from the decomposition of pyrope rather than the akimotoite-bridgmanite transition