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Obtaining horizontal edges and the buried depths of geological bodies, using potential field tensor data directly is an outstanding question. The largest eigenvalue of the structure tensor is one of the commonly used edge detectors for delineating the horizontal edges without depth information of the potential field tensor data. In this study, we presented a normalized largest eigenvalue of structure tensor method based on the normalized downward continuation (NDC) to invert the source location parameters without any priori information. To improve the stability and accuracy of the NDC calculation, the Chebyshev–Pade´ approximation downward continuation method was introduced to obtain the potential field data on different depth levels. The new approach was tested on various models data with and without noise, which validated that it can simultaneously obtain the horizontal edges and the buried depths of the geological bodies. The satisfactory results demonstrated that the normalized largest eigenvalue of structure tensor can describe the locations of geological sources and decrease the noise interference magnified by the downward continuation. Finally, the method was applied to the gravity data over the Humble salt dome in USA, and the near-bottom magnetic data over the Southwest Indian Ridge. The results show a good correspondence to the results of previous work.

Marine gravimeter has been proved to be the primary technique to efficiently obtain middle-to-short wavelength signals of the earth’s gravity field in geodesy, geodynamics and marine sciences research. In recent years, some prototypes of inertial platform and strapdown marine gravimeters have been developed, where the inertial platform gravimeter systems include CHZ-II and ZL11, and strapdown gravimeter systems include SAG-2M and SGA-WZ. In order to validate the performance of these marine gravimeter prototypes, a synchronous test with the widely used gravimeters GT-2M and LCR arranged on the same vessel was carried out in the north of South China Sea. All the data are processed according to the survey standard flow, and the performance is estimated by analyzing the errors of the repeat lines and the crossover points under the same environment. The compared results show that all the six gravimeters can meet the precision requirement of marine gravity survey. Meanwhile, the precision results of the improved gravimeters can get close to the precision of gravimeter GT-2M, higher than the precision gravimeter LCR.

Studies of downward continuation mainly focused on improving the stability more than depth calculation. Stable downward continuation is a promising technique for estimating the depth of sources. In this study, based on the filter curve in wave number domain, a new depth estimation method was developed using the Chebyshev‐Padé downward continuation method. First, the filter curves of Tikhonov regularized method and the Chebyshev‐Padé downward continuation method in wave number domain were compared. We concluded the reason that the Tikhonov regularized method can be used to obtain the depth information is that the filter curve converges to zero. Therefore, to use the Chebyshev‐Padé downward continuation method for calculating the depth, a simple low‐pass filter based on upward continuation was used to improve it in the wave number domain, making the filter curve of the new improved method converge to zero. Similar to the Tikhonov regularized method, our new method can obtain the depth information when calculating downward continuation data from the original level to an expected maximum depth level. To verify the effectivity, different synthetic models were used to test our method, indicating that the new method can achieve a more reasonable depth compared to the Tikhonov regularized method. Finally, the new method was applied to real magnetic data collected using unmanned aerial vehicle aeromagnetic surveys to test on a big car in Southeastern Zhejiang, China. The calculated depth matches with its actual depth. These results show that the new method is a useful depth estimation tool for potential field sources.

A derivative formula for interface inversion using gravity anomalies, combining the Parker–Oldenburg method for calculating and inverting gravity anomalies with Xu’s iteration method for continuing potential fields, leads to a convergent inversion algorithm and an optimally located density interface geometry. In this algorithm, no filtering or any other convergence control techniques are needed during iteration. The method readily iterates the variable depth of the gravity interface by means of upward continuation in a form equivalent to inversion iteration in the Fourier domain instead of the divergent, downward continuation term. This iteration algorithm not only efficiently solves the divergence problem in the inversion iteration procedure but also validly obtains an excellent result for the density interface. A numerical example is presented to illustrate perfect execution of this approach in gravity exploration, and a real geophysical example of inversion of the Moho depth by means of this approach using a set of measured gravity anomalies over the Qinghai–Tibet Plateau in China is offered.

The Gamburtsev Subglacial Mountains are completely buried by the East Antarctic Ice Sheet and hence are one of the most enigmatic tectonic features on Earth. The mountain range is underlain by 50-60 km thick crust and seismically fast Precambrian lithosphere, which is over 200 km thick. Here we present gravity and aeromagnetic images derived from the AGAP aerogeophysical survey, depth to magnetic source estimates and a joint forward magnetic and gravity model along an independent passive seismic line to investigate the crustal structure of the Gamburtsev Province. The magnetic and gravity images reveal three distinct geophysical domains, namely the Northern, Central and Southern Gamburtsev domains, sandwiched in between the South Pole and the Southern Lambert provinces. We interpret these domains as reflecting segments of an inferred early Neoproterozoic (ca 1 Ga) accretionary orogen, which may have been reactivated during Pan-African (ca 550 Ma) collisional events linked to Gondwana assembly. Our gravity model confirms the presence of a dense lower crustal root beneath the northern and central Gamburtsev domains, where the crust is up to 58 km thick. The magnetic modelling suggests that the upper crustal architecture is dominated by south verging thrust faults in the Northern Domain and north verging thrust faults in the Southern Central Domain. Our modelling results are a first step towards comprehending the complex 3D orogenic architecture of the Gamburtsev Province and its broader linkages with Rodinia and Gondwana supercontinent assembly in interior East Antarctica.

This paper is dedicated to an intelligent visualization system for landslide monitoring, whereas wireless sensor network is deployed for observing and detecting the dynamic changes of the landslide body at an experiment site. The visualization system is designed and implemented to visualize the spatial distribution of the employed sensors and the data of these sensors. Through the visualization-supported data analysis, the system will be capable of alert for possible critical events such as landslide surface failure. The experimental results show the initial functions and prototype capabilities of the system.