Synthetic Aperture Radar (SAR) is one of the most widely utilized methods to extract elevation information and identify large-scale deformations in mountainous areas. Homologous points in stereo SAR image pairs are difficult to identify due to complex geometric and radiometric distortions. In this paper, a new approach for mountainous area images is suggested. Firstly, a simulated SAR image and a look-up table based on DEM data are generated by a range-Doppler model and an empirical formula. Then, a point matching RPM-L2E algorithm is used to match images obtained by the simulation and in real-time to indirectly obtain the feature points of the real SAR images. Finally, the accurate registration of mountainous areas in the SAR images is achieved by a polynomial transform. Experimental verification is performed by using the data of mountainous SAR images from the same sensor and different sensors. When the registration accuracy of the method is compared with that of two state-of-the-art image registration algorithms, better outcomes are experimentally shown. The suggested approach can effectively solve the registration problem of SAR images of mountainous areas, and can overcome the disadvantages of poor adaptability and low accuracy of traditional SAR image registration methods for mountainous areas.

Landslide extraction is one of the most popular topics in remote sensing. Numerous techniques have been proposed to manage the landslide identification problem. However, most aim to extract landslides that have already occurred or delineate the potential landslide manually. It is greatly important to identify and delineate potential landslides automatically, which has not been investigated. In this paper, we propose an automatic identification and delineation method, i.e., object-based image analysis (OBIA) of potential landslides by integrating optical imagery with a deformation map. We applied a deformation map generated by the interferometric synthetic aperture radar (InSAR) technique, rather than the digital elevation model (DEM) for landslide segmentation. Then, we used a classification and regression tree (CART) model with the spectral, spatial, contextual and deformation characteristics for landslide classification. For accuracy assessment, we implemented the evaluation indicators of recall and precision. The proposed method is verified in both specific landslide-prone regions (Jinpingzi and Shuanglongtan landslides) and a large catchment of the Jinsha River, China. By comparing our results with the ones using purely optical imagery, the precision of the Jinpingzi landslide is improved by 14.12%, and the recall and precision of the Shuanglongtan landslide are improved by 3.1% and 3.6%, respectively, and the recall for the large catchment is improved by 9.95%. Our method can improve delineation of potential landslides significantly, which is crucial for landslide early warning and prevention.

The distribution and characteristics of geological lineaments in areas with active faulting are vital for providing a basis for regional tectonic identification and analyzing the tectonic significance. Here, we extracted the lineaments in the Qianhe Graben, an active mountainous area on the southwest margin of Ordos Block, China, by using the tensor voting algorithm after comparing them with the segment tracing algorithm (STA) and LINE algorithm in PCI Geomatica Software. The main results show that (1) the lineaments in this area are mostly induced by the active fault events with the main trending of NW–SE, (2) the box dimensions of all lineaments, NW–SE trending lineaments, and NE–SW trending lineaments are 1.60, 1.48, and 1.44 (R2 > 0.9), respectively, indicating that the faults exhibit statistical self-similarity, and (3) the lineaments have multifractal characteristics according to the mass index τ(q), generalized fractal dimension D(q), fractal width (Δα = 2.25), fractal spectrum shape (f(α) is a unimodal left-hook curve), and spectrum width (Δf = 1.21). These results are related to the tectonic activity in this area, where a higher tectonic activity leads to more lineaments being produced and a higher fractal dimension. All of these results suggest that such insights can be beneficial for providing potential targets in reconstructing the tectonic structure of the area and trends of plate movement.

The morphology of watershed is the most intuitive information carrier to reflect regional tectonic activity, surface erosion and morphologic evolution. Active tectonic and fluvial system play a significant role in patterns and characters of regional morphology. Taking twenty-nine tributaries of the upper reaches of the Weihe River as the main study objects, four parameters, such as gully density (GD), basin topography ratio (BTR), roundness ratio (RR), river longitudinal profile fitting exponent (RLPFE), etc., were used to quantitatively analyse the topographic characteristics in this area. To reveal the main cause of the characteristics, the hypsometric integral (HI) were also applied in this area. The results showed that: (1) There is a positive linear function between basin topography ratio (BTR) and mean slope, and the mean values of four indexes in northern channels are smaller than southern channels; (2) The mean HI value is 0.44, indicating that the main topographic characteristics of this area is in maturity, which is in the transitional period of adjustment of the deep erosion and uplift movement; (3) The main cause of this topographic changes is tectonic. These results are consistent with other geological background, and will enrich regional basin morphology research and tectonic activity evaluation, provide important basic data for regional disaster prediction and analysis of soil and water loss.

Since the late Cenozoic era, due to the impact of the Indo- Eurasian plate collision and the northeasterward compression of the Tibetan Plateau, a series of extensional sub-basins and tectonic belts have been formed at the periphery of the Ordos block. Watershed geomorphology plays an important role in studying the formation of rock uplift and river erosion, and are recording the surface evidence on landforms evolution. In this paper, twenty-eight sub-basins and tributaries around Daxihe River, locating at the southern margin of Ordos, were extracted from SRTM1 DEM data. Combined with Hack profile and related river parameters, the tectonic and geomorphic morphology were evaluated synthetically. The results show that (1) The mean SL of this area is 93.9, indicating that the tectonic activities are strong in Daxihe River Basin; (2) The SL values of the northern and southern are 58.9–152 and 66–137.4, respectively, showing that the uplift rate of eastern margin larger than the southern margin; (3) There are positive power functions between K and drainage area, also between landform relief and slope. This study plays an auxiliary role in regional geological background, structural activity analysis and disaster prediction.