To better understand the Wudalianchi intraplate volcanism and mantle dynamics in NE China, we collect abundant teleseismic waveform data during 2008 to 2018 recorded at 259 seismic stations around the Wudalianchi volcano. These stations include 148 WAVESArray portable stations, 66 NECESSArray portable stations and 45 Chinese provincial stations. Our newly deployed WAVESArray makes the station intervals of ~20–30 km around the Wudalianchi volcano. Using the minimum transverse‐energy grid‐search method, we make effective SKS splitting measurements at 192 stations. Our results show that the fast direction in the study region is mainly NW‐SE, but there are obvious contrasts within and between different tectonic units. To the east of the North‐South Gravity Lineament, around the Wudalianchi volcano, our SKS splitting measurements show a southeastward opening U‐shaped pattern in the fast direction and splitting time. Such a pattern of seismic anisotropy could be caused by horizontal and vertical flows in the big mantle wedge due to the deep subduction, long stagnancy, and deep dehydration of the Pacific slab in the mantle transition zone. The horizontal flow in the big mantle wedge could be obstructed by the thicker lithosphere under the Great Xing'an range and disturbed by hot and wet upwelling flow under the Wudalianchi volcano. Around the Nuominhe and Halaha volcanic groups, variations in the splitting parameters may also be associated with lithospheric deformation and delamination, though they are located at the edge of our study region. These results shed new light on the intraplate volcanism and mantle dynamics in NE China.

Massive lithospheric thinning occurred in eastern China and large‐scale magmatism in South China occurred in the Mesozoic. Some geodynamic models have been proposed to explain their mechanisms, but are not consistent with each other. We apply anisotropic tomography to 32,728 P‐wave travel time data of 479 teleseismic events recorded at 225 stations to study the 3‐D anisotropic Vp structure of the upper mantle beneath central‐east China. P‐wave radial anisotropy is investigated for the first time in the study region. Our results show that an obvious low‐velocity zone exists in the asthenosphere under the eastern part of our study region, which represents upwelling thermal flow from the Cathaysia block to the North China block (NCB) according to the results of azimuthal and radial anisotropies. A distinct high‐velocity zone with weak radial anisotropy exists under the middle Yangtze block, which is explained as the stable cratonic root. Two other weak high‐velocity zones appear near or within the mantle transition zone under the middle‐lower Yangtze River and the eastern NCB, which might be detached lithosphere or the stagnant Pacific slab. Combining with previous geological and geochemical results, we consider that both the NCB and the South China block have undergone a common geodynamic process in the Mesozoic due to their similar age trending of igneous rocks, which could be explained by a flat‐slab subduction model and a ridge subduction model. These two models are associated with the paleo‐Pacific plate subduction that might have played a key role in the evolution of eastern China.

Gravity data have been frequently used in researching the subsurface to map the 3D geometry of the density structure, which is considered the basis for further interpretations, such as the estimation of exploration potential in mineral exploration. The gravity inversion, practically employed to map the density structure, can be achieved by different methods. The method based on Tikhonov regularization is the most commonly used among them. Usually, the subsurface is discretized into a set of cells or voxels. To recover a stable and reliable solution, constraints are introduced into the Tikhonov regularization. One constrained inversion introduces a quadratic penalty (L₂ norm) into the inversion, which imposes smooth features on the recovered model. Another gravity inversion, known as sparse inversion, imposes compactness and sharp boundaries on the recovered density structure. Specifically, the L₁ norm and L₀ norm are favored for such a purpose. This work evaluates the merits of the gravity data inversion in cooperation with different model norms and their applicability in exploration potential estimation. Because these norms promote different features in the recovered models, the reconstructed 3D density structure reveals different geometric features of the ore deposit. We use two types of synthetic data for evaluating the performances of the inversion with different norms. Numerical results demonstrate that L₀ norm-based inversion provides high-resolution recovered models and offers reliable estimates of exploration potential with minimal deviation from theoretical mass compared to inversions equipped with the other two norms. Finally, we use the gravity data collected over the iron ore deposit at the Dida mining area in Jilin province (Northeast China) for the application. It is estimated that the exploration potential of the iron ore deposits is about 3.2 million tons.