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The Shandong Peninsula is located in the eastern part of the North China Craton (NCC). Influenced by the collision between the North and South China blocks and the subduction of the Pacific Plate, the tectonic evolution process is highly complex. Previous studies have proposed that the thick cratonic root beneath the eastern NCC has been destructed. To better understand the relationship between the craton reactivation and the deep subduction, more constraints on the topography variations of the mantle transition zone (MTZ) discontinuities are required. In this study, we stacked 9073 P‐to‐S receiver functions calculated from 129 broadband seismic stations to image the depth variations of the MTZ discontinuities beneath the Shandong Peninsula and its adjacent area. To decrease the influence of velocity anomaly above the MTZ discontinuities, we converted the apparent depths into corrected depth using regional and global 3D velocity models. The apparent depth of the 410‐km discontinuity exhibits a depression of approximately 6 km, which normalizes after velocity correction. This implies the existence of the low‐velocity anomaly in the upper mantle, possibly caused by slab dehydration and water infiltration into the upper mantle. The significant depression of the 660‐km discontinuity indicated the presence of the cold Pacific slab stagnating at the base of the MTZ. The gradual westward depression of the 660‐km discontinuity by 50 km could provide evidence for the sinking of the western margin of the flat‐lying subducting Pacific slab in the MTZ beneath the Shandong Peninsula. [ABSTRACT FROM AUTHOR]

To provide constraints on a number of significant controversial issues related to the structure and dynamics of the Australian continent, we utilize P -to- S receiver functions (RFs) recorded by 182 stations to map the 410 and 660 km discontinuities (d410 and d660, respectively) bordering the mantle transition zone (MTZ). The RFs are stacked in successive circular bins with a radius of 1° under a non-plane wave front assumption. The d410 and d660 depths obtained using the 1-D IASP91 earth model show a systematic apparent uplifting of about 15 km for both discontinuities in central and western Australia relative to eastern Australia, as the result of higher seismic wave speeds in the upper mantle beneath the former area. After correcting the apparent depths using the Australian Seismological Reference Model, the d410 depths beneath the West Australia Craton are depressed by ∼10 km on average relative to the normal depth of 410 km, indicating a positive thermal anomaly of 100 K at the top of the MTZ which could represent a transition from a thinner than normal MTZ beneath the Indian ocean and the normal MTZ beneath central Australia. The abnormally thick MTZ beneath eastern Australia can be adequately explained by subducted cold slabs in the MTZ. A localized normal thickness of the MTZ beneath the Newer Volcanics Province provides supporting evidence of non-mantle-plume mechanism for intraplate volcanic activities in the Australian continent. [ABSTRACT FROM AUTHOR]