## 1 Introduction  
The Eastern Kunlun Fault constitutes a significant fault zone characterized by primarily sinistral strike-slip movement. It originated along the Eastern Kunlun Vanirscan paleo-tectonic suture within the Tibetan Plateau due to the collision between the Indian and Asian plates. This fault spans approximately 2000 km, following a general west-northwest trend, extending from the west of Bukedalban Peak, situated north of Hoh Xil Lake in Qinghai province, to the Maqu region in Sichuan province [1] (Figure 1). Situated at the northern margin of an upwelling area in the middle of the Tibetan Plateau, the primary portion of this fault zone lies approximately along the 64-km depth contour of the Moho surface, extending in an east-west direction. An isobathic line from the southeast of Maduo-Maqu to the Mohorovicic discontinuity shifts southward, coinciding with a gradual reduction in crustal thickness along this trajectory [2]. Recent seismic refraction data reveal that the crustal thickness of the BaiYan Har Mountain Group, positioned in the southern sector of the fault zone, measures 64 km. This thickness notably decreases to 60 km as one progresses northward, reaching the southern rim of the Qaidam Basin and the Touraine area. This creates a region characterized by variable crustal thickness in the west-northwest direction. The Moho topography and crustal flow mechanism within this fault zone have experienced discernible shifts, delineated by the Aemye Ma-chhen Mountains in an east-west orientation [3,4]. As a result, this paper employs the Aemye Ma-chhen Mountains as a reference to partition the Eastern Kunlun Fault into eastern and western segments, building upon the geometric structural attributes of the fault zone in conjunction with geophysical data. Since 1900, five earthquakes with magnitudes exceeding 7.0 have occurred in the western part of the Aemye Ma-chhen Mountains in the Eastern Kunlun fault, encompassing the Ms 7.9 Mani earthquake in 1997, Ms 8.1 Kunlun Mountains earthquake in 2001, Ms 7.0 Xiugou earthquake in 1902, Ms 7.1 Akake Lake earthquake in 1963, and Ms 7.5 Tuosuohu earthquake in 1937 (Figure 1). As depicted in Figure 1, there is a notable absence of documented large earthquakes (Ms \(\geq\) 7) in the historical records of the eastern segment of the Eastern Kunlun Fault, marking it as a distinctive seismic gap within this fault zone. Moreover, the Wenchuan earthquake of 2008 heightened the accumulation of Coulomb stress within the eastern segment of the Eastern Kunlun Fault zone [5], consequently elevating the latent risk of earthquakes in this section. Therefore, the Maqin-Maqu segment, constituting the eastern part of the Eastern Kunlun Fault zone, emerges as the seismic gap with the highest population density along the entire fault zone. As such, there is an exigent need to scrutinize the earthquake risk and forecast potential large-scale seismic events. To predict earthquakes in the medium and long term, a quantitative approach involves expressing the likelihood of earthquake occurrence as a probability [6; 7]. Assuming that the time for earthquake occurrence approximately follows a specific recurrence model [8; 9], we can employ this model to estimate the probability of recurrent major earthquakes within a defined time frame [10; 11; 12]. Many research findings indicate that the model may exhibit various distribution types, including normal, logarithmic normal, and Weibull distributions. In the northeastern Tibetan Plateau, occurrences of severe earthquakes are relatively frequent, and research on ancient earthquakes along the fault zone is notably extensive. In this study, through the collection and analysis of data regarding ancient earthquakes, we ascertain sample parameters and derive the probability density function  
Figure 1: Topographic map of the northern Tibetan Plateau region. Major active faults are adapted from [PERSON] et al., 2007 [1]. The upper-left figure shows the location of Northern Tibet.