###### Abstract  
A microseismic (MS) monitoring system was established, and numerical modeling was performed using Fast Lagrangian Analysis of Continua in 3 Dimensions (FLAC3D) to examine the evolution characteristics of MS events during the excavation of underground caverns under high geostress. Specifically, the spatial and temporal damage characteristics of the rock mass, the dynamic relationship between the evolution of MS events, the site construction conditions, and the geological structures under high geostress were also analyzed. In addition, a three-dimensional numerical model of underground caverns was built to demonstrate the deformation characteristics of the rock mass. As a result, the characteristics of a large number of MS events, multiple concentration zones of MS events, and long periods of stress adjustment were discovered in underground caverns under high geostress. It was found that the primary cause of MS events was site blasting construction. In particular, the distribution of the MS events was strongly correlated with the location of the site blasting construction, and the frequency of the MS events was positively correlated with it. The structural plane is a discontinuous plane with very low or no tensile strength, and its presence also increased the number of MS events and raised the possibility of the surrounding rock becoming unstable. Moreover, the MS monitoring data agreed with the numerical modeling results, which can be useful in estimating damage to underground caverns under high geostress and predicting disasters. high geostress; underground powerhouse; MS monitoring; characteristic; numerical modeling 22 November 202  
problems, including rock deformation and rock bursts caused by tunnel excavation and unloading, are prominent, which represents a great challenge to tunnel construction safety. Field monitoring is being applied more frequently in underground projects, which not only ensures the safety of a construction site to a certain extent but also provides the data basis for other methods, such as mechanical analysis, numerical modeling, and physical model tests [2]. It can also be used to demonstrate the safety of projects in many different ways and assess the stability of the surrounding rocks. Traditional monitoring tools (such as multipoint displacement meters and rock bolt stress meters) are mainly used to measure rock deformation and bolt stress, as they directly collect field data of changes in rock deformation and bolt stress, thus, playing an important role in the analysis and control of rock stability. Field remedies, however, are challenging to provide promptly since traditional monitoring tools frequently obtain monitoring results after the rock mass has already sustained damage or perhaps has become unstable [3]. In contrast, the data on MS events in advance, such as time, location, and strength, can be collected by MS monitoring before the rock becomes unstable or large deformations occur during geotechnical engineering. The stability of engineering rocks can be assessed. Therefore, it allows for a timely warning of large deformations or even instability of the surrounding rock and provides important technical support for engineering construction safety. Currently, MS monitoring is widely used in western countries for studying and preventing dynamic disasters, particularly in mines [4; 5; 6], tunnels [7; 8], exploitation of oil, gas, and geothermal energy [9; 10; 11], and underground storage [12]. [PERSON] et al. [5] located MS events at the Schlema-Alberoda uranium mine in Southwest Saxony, Germany, to study the nature of seismicity and the long-term role of mining-induced and triggered seismicity. [PERSON] et al. [6] used MS data recorded during underground mine developments for 3D attenuation tomography, which can help to delineate the ore body using seismic waves and other measurement methods, such as gravity inversion and borehole sampling.