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Glacial Lake Outburst Flood (GLOF) events, particularly prevalent in Asia's High Mountain regions, pose a significant threat to downstream regions. However, limited understanding of triggering mechanisms and inadequate observations pose significant barriers for early warnings of impending GLOFs. The 2018 Nyalam GLOF event in southern Tibet offers a valuable opportunity for retrospective analysis. By combining optical and radar remote sensing images, meteorological data, and seismicity catalogs, we examined the spatiotemporal evolution, triggering factors, and the outburst mechanism of this event. Our analysis reveals a progressive retreat of 400–800 m for the parent glaciers between 1991 and 2018, increasing the runoff areas at glacier termini by 167% from 2015 to 2018 and contributing abundant meltwater to the glacial lake. In contrast, the lake size shrunk, potentially due to a weakening moraine dam confirmed by SAR interferometry, which detected continuous subsidence with a maximum line-of-sight (LOS) rate of ~120 mm/a over the preceding ~2.5 years. Additionally, temperature and precipitation in 2018 exceeded the prior decade's average. Notably, no major earthquakes preceded the event. Based on these observations, we propose a likely joint mechanism involving high temperatures, heavy precipitation, and dam instability. An elevated temperature and precipitation accelerated glacial melt, increasing lake water volume and seepage through the moraine dam. This ultimately compromised dam stability and led to its failure between 3 August 2018 and 6 August 2018. Our findings demonstrate the existence of precursory signs for impending GLOFs. By monitoring the spatiotemporal evolution of environmental factors and deformation, it is possible to evaluate glacial lake risk levels. This work contributes to a more comprehensive understanding of GLOF mechanisms and is of significant importance for future glacial lake risk assessments. [ABSTRACT FROM AUTHOR]

The Lenglongling Fault Zone (LLLFZ) is an important left‐lateral strike‐slip tectonic belt in the northeastern Tibetan Plateau (NETP), and the tectonic deformation and seismic activity of the LLLFZ reflect tectonic adjustments of the Qilian‐Haiyuan tectonic zone to the NETP. Although historical records of large earthquakes along the LLLFZ are not available, offset landforms reveal that large earthquakes have occurred. Therefore, offset landforms are used to study the seismic slip distribution to determine a fault slip model and earthquake recurrence behaviour based on an analysis of high‐resolution remote sensing images. Geomorphic markers associated with 316 systematically sinistrally deflected landforms were measured and analysed. The cumulative offset probability densities were analysed according to slip distributions measured along two segments of the fault. Offset density peaks in the eastern section of the fault decay exponentially with increasing offset size, suggesting that approximately seven palaeoearthquakes with an average slip of approximately 8 m occurred during the Holocene. The cumulative slips in the western segment increase gradually from west to east, with single‐event slips of approximately 2–3 m in the western part of the western segment and approximately 5–7 m in the eastern part. The seismic slip distributions of the LLLFZ indicate that the fault conforms to a quasi‐characteristic slip model. Both the eastern and western segments present typical left‐lateral strike‐slip movement. A magnitude of 8.0 was estimated for the LLLFZ palaeoearthquakes that occurred during the Holocene according to empirical relations. This study is helpful for understanding the tectonic deformation of the NETP. [ABSTRACT FROM AUTHOR]

In this study, multitemporal satellite images, unmanned aerial vehicle (UAV) photogrammetry and ground-based radar were utilized to investigate the formation mechanism and disaster features of different phases of the Xuyong landslide disaster that occurred in Sichuan Province on December 9, 2018. Field survey indicates that the estimated landslide volume is approximately 35000 m3. The landslide is a typical dualistic soil-rock structural landslide with bedding planes. The sliding surface is located in a thin layer of limestone which is characterized by the X-shaped conjugate joint planes. The steep slope has been cut and transformed by human disturbances, which have influenced the slope stability and the drainage of precipitation along the slope. Many factors, including the regional geological structure, stratum lithology, slope topography, landform morphology, and precipitation, have contributed to the Xuyong landslide during the pre-disaster phase. Post-disaster emergency observation revealed that subsequent deformation was located mainly along the back edge of the landslide, where the maximum surficial deformation reached only 18 mm/day over a small area, reflecting the low probability of a secondary landslide hazard. Our research provides significant guidelines for investigating potential landslide dangers in similar environments and for post-disaster emergency response using multiple remote sensing (RS) platforms. [ABSTRACT FROM AUTHOR]