On August 31, 2025, a magnitude M_W6.1 earthquake occurred in the Hindu Kush Mountains region of eastern Afghanistan, near Kunar and Nangarhar provinces, causing a large number of casualties and property damage. The earthquake further exacerbated the risk of disaster in the region due to Afghanistan's location in the intra-continental deformation zone at the junction of the Eurasian and Indian plates, with active tectonic activity, and the country has long faced a humanitarian crisis and weak infrastructure. In order to reveal the disaster characteristics of this earthquake, based on the Sentinel-1 satellite data, this paper uses Interferometric Synthetic Aperture Radar (InSAR) to carry out coseismic deformation monitoring, and uses the coseismic deformation field as the constraint to invert the source parameters and static sliding distribution. The results show that the rupture depth of the earthquake is shallow, mainly concentrated within 8 km underground. The rupture is dominated by thrust motion and has a small tilt-slip component, with a maximum sliding amount of 2.5 m. At the same time, there were many strong aftershocks after the earthquake, the terrain of the earthquake area was steep, and many landslides occurred after the earthquake, and a large number of mud brick houses collapsed. As of September 4, 2025, the Afghan Red Crescent Society confirmed that the earthquake killed 3, 073 people and injured 3, 640, making it the deadliest earthquake event in Afghanistan in recent years. In view of the complex topography, poor building quality and dense population in the local area of the earthquake, this paper studies the population casualties and spatial distribution laws. The results show that the casualty population is highly concentrated in the river valleys and towns in the southern part of Kunar province and the northern part of Nangarhar province, which is closely related to the characteristics of local population aggregation along the river valley and the extremely poor seismic performance of traditional mud brick and adobe houses. Therefore, it is necessary to continue to pay attention to the secondary disaster hazards in the earthquake area and conduct multi-dimensional regional disaster risk assessment to reduce the systemic crisis in Afghanistan.