The middle reaches of the upstream of Jinsha River (MRUJR) is located in the eastern segment of the Jinsha River suture zone on the southwest of China. A study of the MRUJR based on tectonic geomorphology is noteworthy for providing a profound understanding of the tectonic transition between the Sichuan‐Yunnan and Qamdo blocks and active tectonics in various subbasins. Based on the global digital elevation model Shuttle Radar Topography Mission 1 (30 m resolution) data and geographic information system techniques, four geomorphic indices, the hypsometric integral, stream length‐gradient, drainage basin asymmetry, and drainage basin shape were calculated and analysed. Combined with geologic evidence from field surveys and fault slip rates estimated, the tectonic activities and mechanisms were discussed. Through the specific analytical comparisons, the variations in the geomorphic indices were unlikely affected by lithology and climate but showed changes in relevant tectonic activity. The analysis results of geomorphic index value manifested related strong activities in the northwestern and southeastern regions of MRUJR, tilt directions are mainly SW–NE and NE–SW, respectively. The MRUJR is undergoing rapid uplift. These results are consistent with the field evidence.
Landslides have attracted extensive attention and research worldwide because of their tremendous destructiveness, and many catastrophic landslides have occurred along river corridors and reservoir bank slopes. The detection and detailed monitoring of potential landslides are prerequisites for landslide disaster prevention, with recent advance in spaceborne Interferometric Synthetic Aperture Radar (InSAR) having effectively addressed this challenge. In this study, a wide-area landslide detection and monitoring framework, combining multiple InSAR techniques, is proposed to investigate active landslides along the upper reaches of the Yellow River from Longyang Gorge to Liujia Gorge (UYRLL), north-west China. A total of 597 active landslides have been mapped in this region for the first time. Our analyses suggest that a large percentage of the detected landslides are distributed at an elevation of 2,000-3,000 m with slope angles of 5-30° and their spatial distribution density is correlated with regional tectonic activity. Multi-Temporal InSAR (MTI) techniques have also been adopted to analyze the surface motion characteristics of two typical landslides (i.e., the Lijia landslide and the Xijitan landslide), showing that these two landslides are dominated by linear motion. The landslide movements also contain slight non-linear oscillations, inferred
Currently available high-resolution digital elevation model (DEM) is not particularly useful to geologists for understanding the long-term changes in fluvial landforms induced by tectonic uplift, although DEMs that are generated from satellite stereo images such as the ZiYuan-3 (ZY3) satellite include characteristics with significant coverage and rapid acquisition. Since an ongoing analysis of fluvial systems is lacking, the ZY3 DEM was generated from block adjustment to describe the mountainous area of the Qianhe Basin that have been induced by tectonic uplift. Moreover, we evaluated the overall elevation difference in ZY3 DEM, Shuttle Radar Topography Mission (1″ × 1″) (SRTM1), and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM) by using the Ice Cloud and Land Elevation Satellite/Geoscience Laser Altimeter (ICESat/GLAH14) point cloud and a DEM of 1:50,000 scale. The values of the root mean square error (RMSE) of the elevation difference for ZY3 DEM were 9.31 and 9.71 m, respectively, and are in good agreement with SRTM1. The river long profiles and terrace heights were also extracted to compare the differences in channel steepness and the incision rates with SRTM1 and ASTER GDEM. Our results prove that ZY3 DEM would be a good alternative to SRTM1 in achieving the 1:50,000 scale for DEM products in China, while ASTER GDEM is unsuitable for extracting river longitudinal profiles. In addition, the northern and southern river incision rates were estimated using the ages and heights of river terraces, demonstrating a range from 0.12–0.45 to 0.10–0.33 m/kyr, respectively. Collectively, these findings suggest that ZY3 DEM is capable of estimating tectonic geomorphological features and has the potential for analyzing the continuous evolutionary response of a landscape to changes in climate and tectonics.
The drainage basin of the upper reaches of the Yellow River from Lagan Gorge to Liujia Gorge, which spans Gonghe, Guide, Jianzha, Xunhua and Linxia basins, is located in the transition zone between the Qinghai-Tibet Plateau and the Loess Plateau, northwestern China. Its evolution is controlled by the northeastward growth and uplift of the Qinghai-Tibet Plateau. To characterize and quantify the response of surface processes to deep geological mechanisms and to investigate the types of Late Cenozoic tectonic deformation in the study area and the relationship with large geological hazards, we analysed various geomorphological indicators, combined with field observations and the estimated incision rates and established a reasonable tectonic deformation model. The results demonstrate that the variations in the geomorphic indices are highly consistent with active tectonics. Higher hypsometric integral (HI), higher normalized stream length-gradient index (SLK), higher basin asymmetry factor (AF), higher drainage basin shape (BS) and lower ratios of valley floor width to valley height (VF) indicate higher tectonic uplift rate in the Jianzha-Xunhua basins compared to other basins where there are many giant landslides. These giant landslides occurring there can probably be correlated with the vigorous tectonic activity, thus generating a great significance in geological hazard prevention and control along the upper Yellow River.
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