The microtremor exploration technique has been widely used in the geological exploration of a complex urban environment due to its strong spatial adaptability and anti-mechanical interference ability.The forward modeling of microtremor characteristic curves is all based on a horizontally layered medium model,while actual strata are typical inhomogeneous geological models.The inconsistency leads to the unsatisfactory fitting degree of characteristic curves.Therefore,it is necessary to conduct forward modeling research based on the condition of inhomogeneous media.Since the geological model based on the assumption of horizontally layered media cannot meet the requirements for high-precision forward modeling of microtremor characteristic curves,forward modeling needs to be conducted using an inhomogeneous model.Based on the dynamic optimization method,this study proposed the forward modeling technique of microtremor characteristic curves to realize the forward modeling of high-precision characteristic curves of inhomogeneous media.In this technique,the aperture range and the optimization coefficients varying with frequency were calculated based on the theoretical characteristic curves of equivalent horizontally layered media.Taking spectral ratio curves as an example,the forward modeling technique of microtremor characteristic curves using the dynamic optimization method can obtain the shear wave distribution of inhomogeneous media through inversion,achieving higher lateral resolution and exploration precision.
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