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The accurate prediction of landslide susceptibility relies on effectively handling landslide absence samples in machine learning (ML) models. However, existing research tends to generate these samples in feature space, posing challenges in field validation, or using physics-informed models, thereby limiting their applicability. The rapid progress of interferometric synthetic aperture radar (InSAR) technology may bridge this gap by offering satellite images with extensive area coverage and precise surface deformation measurements at millimeter scales. Here, we propose an InSAR-based sampling strategy to generate absence samples for landslide susceptibility mapping in the Badong–Zigui area near the Three Gorges Reservoir, China. We achieve this by employing a Small Baseline Subset (SBAS) InSAR to generate the annual average ground deformation. Subsequently, we select absence samples from slopes with very slow deformation. Logistic regression, support vector machine, and random forest models demonstrate improvement when using InSAR-based absence samples, indicating enhanced accuracy in reflecting non-landslide conditions. Furthermore, we compare different integration methods to integrate InSAR into ML models, including absence sampling, joint training, overlay weights, and their combination, finding that utilizing all three methods simultaneously optimally improves landslide susceptibility models. [ABSTRACT FROM AUTHOR]

Archaeological predictive modeling (APM) is an essential method for quantitatively assessing the probability of archaeological sites present in a region. It is a necessary tool for archaeological research and cultural heritage management. In particular, the predictive modeling process could help us understand the relationship between past human civilizations and the natural environment; moreover, a better understanding of the mechanisms of the human–land relationship can provide new ideas for sustainable development. This study aims to investigate the impact of topographic and hydrological factors on archaeological sites in the Japanese archipelago and Shaanxi Province, China and proposes a hybrid integration approach for APM. This approach employed a conditional attention mechanism (AM) using deep learning and a frequency ratio (FR) model, in addition to a separate FR model and the widely-used machine learning MaxEnt method. The models' outcomes were cross-checked using the four-fold cross-validation method, and the models' performances were compared using the area under the receiver operating characteristic curve (AUC) and Kvamme's Gain. The results showed that in both study areas, the AM_FR model exhibited the most satisfactory performances. [ABSTRACT FROM AUTHOR]

A 100-year sedimentary record in the Changjiang Estuary was examined to elucidate natural and anthropogenic influences on the morphodynamic evolution of the estuary. Two gravity cores were acquired and their magnetic properties, sediment size, chemical elements and Pb geochronology were analyzed to infer the sedimentation. The results indicate that these sedimentological indexes, especially magnetic properties and trace elements, changed significantly during the last 100 years, with an abrupt change occurring at around 1960. This abrupt change is likely the result of a reduction in hydrodynamic energy caused by the narrowing of an upstream estuary reach due to reclamation. An increase of terrigenous input, due to soil erosion in the upper and middle reaches of the Changjiang, and increases in steel production may have also had a significant influence, as indicated by studies of other locations in the Changjiang drainage basin. [ABSTRACT FROM AUTHOR]

Abstract: There has been limited detailed geomorphological research on the Kangding fault system, located along the eastern margin of the Tibetan Plateau, despite the system containing active faults with high slip rates. Fault-related landforms such as offset streams were mapped at selected sites along the Zemuhe and Xiaojiang faults in the central and southern sections of the Kangding fault system. The results permitted assessment of the mode and rate of late Quaternary fault movement based on more comprehensive information than used in previous studies. The left-lateral strike-slip of these faults reflects the large-scale clockwise rotation of the Southern Tibetan Plateau. The estimated strike-slip rate of the Zemuhe fault is ca. 5–9 mm yr−1, whereas that of the Xiaojiang fault is ca. 14–22 mm yr−1. These rates and the known slip rates of the adjacent faults indicate that, in the northern and southern sections of the Kangding fault system, the regional tectonic stress from the clockwise rotation has been released mainly along the major faults; whereas, the stress in the central section has been released by both fault movement and deformation in surrounding areas. The latter mechanism reflects a more complex geological structure in the central system of distinct thrusts and folds. Late Quaternary vertical deformation along the Zemuhe and Xiaojiang faults has mostly resulted from local stresses associated with strike-slip movement, although the Zemuhe fault has also undergone slow but consistent normal faulting since the early Quaternary due to its orientation oblique to the direction of the clockwise rotation. [Copyright &y& Elsevier]

Abstract: Mud deposits are widespread in estuaries and on continental shelves, and contain important information regarding interactions between terrestrial and coastal processes. Magnetic properties of muddy sediments from the northeastern continental shelves of China, including shelves close to Korean coasts, were analyzed using bulk and size-fractionated samples to elucidate muddy sediment sources and transport. Types, concentration, and granulometry of magnetic minerals were determined and all samples were found to be dominated by magnetite. Muddy sediments from the Zhemin coast (off the Zhejiang and Fujian coasts) have the highest magnetic susceptibility (χ) and saturation isothermal remanent magnetization (SIRM) values, while those from the central and southeastern South Yellow Sea and the western Korea Strait have lower values reflecting lower magnetic mineral concentrations. Single domain ferrimagnetic grains dominate the magnetic particles in the central South Yellow Sea, while superparamagnetic (SP) grains contribute significantly to the magnetic grains in the Bohai Sea. SP and coarse multi-domain (MD) grains dominate magnetic grain assemblages in the North Yellow Sea and along the Zhemin Coast. Rock sediment particle size is not a major factor affecting the magnetic properties of the mud deposits in the study area. Rather, terrigenous inputs and hydrodynamic transport processes primarily control the magnetic properties, and sediments from the Changjiang and Huanghe rivers make the most significant contribution. This observation applies to the whole study area, although terrigeneous magnetic mineral concentrations decrease with increasing distance from the river mouths due to both sorting and mixing with other sediments with weak magnetic signatures. Bacterial magnetosomes also play a role in the central South Yellow Sea. [Copyright &y& Elsevier]

Abstract: Provenance discrimination of marine sediments is an important topic in marine geology. Although the catchments of the Changjiang and Huanghe Rivers are regarded as the main sources of sediments on the shelves of the China Sea, identification of detailed sediment provenance is necessary for understanding sediment transport patterns and the paleoenvironment. Magnetic properties of both bulk sediment samples and different-sized particles from the Changjiang and Huanghe Estuaries are studied to discuss the origin of the sediments. The results show that the sediments are dominated by ferrimagnetic magnetite with a minor content of anti-ferromagnetic minerals such as hematite, and a higher concentration of ferrimagnetic minerals is observed for the Changjiang Estuary sediments. The crystal grains of ferrimagnetic minerals in the Changjiang Estuary are coarser than those in the Huanghe Estuary, whereas superparamagnetic grains significantly contribute to the Huanghe sediments. Magnetic parameters of χ SIRM, SOFT and χ ARM from different-sized particles present more obvious differences than these parameters from bulk particles, and S−100 and S−300 for both bulk samples and different-sized particles show distinct differences between the sediments from the two estuaries. Therefore the latter parameters are more useful to distinguish sediment origins. A comparison of the magnetic properties of sediments in these two estuaries with those on the shelves of the adjacent China Sea also suggests that the analysis of sediment magnetic properties is effective to identify sediment provenances. [Copyright &y& Elsevier]