The invention discloses a stochastic finite fault
source model establishment method, which comprises the following steps of S1, determining a geometrical shape of a seismic fault based on regional geological data and seismic
monitoring data, and estimating a non-planar fault parameter and a
fault plane average sliding amount in combination with historical data and an
empirical formula; s2, estimating distribution and sliding strength of concave-convex bodies and obstacles on the fault surface according to historical
seismic inversion data, and obtaining the sliding amount of each sub-fault by randomly disturbing the average sliding amount; s3, the discrete
fault plane serves as a sub-fault unit, and after an initial fracture point and the average fracture speed are determined, random fracture initial time conforming to normal or power law distribution is generated based on a random number method; s4, calculating the seismic oscillation
time history of each sub-fault by adopting a random
point source method, superposing contributions, introducing the influence of a shallow velocity structure V30, and generating a three-dimensional seismic oscillation field; and S5, comparing actual strong earthquake
record adjustment parameters, and outputting a multi-risk-level earthquake
motion parameter evaluation result after iterative optimization. According to the method, by fusing randomness and
empirical data, the
simulation precision of the seismic
source model on the uncertainty of the seismic process is improved, the influence of the potential maximum-magnitude earthquake possibly occurring in the
active fault zone in the future can be effectively estimated, the seismic oscillation
simulation precision and the calculation efficiency can be improved, and the method is suitable for
engineering structure aseismic design and seismic disaster evaluation.