| 摘要 |
PURPOSE:To accurately analyze the characteristics of a multilayered sedimentary layer even when damping coefficient is not proportional to frequency, by calculating the underwater sonic wave reflection coefficient at the boundary surface of each sedimentary layer while calculating the damping coefficient of each layer on the basis of the calculated result to determine the density of each layer. CONSTITUTION:The inpulse response spectrum of each sedimentary layer is calculated from a sonic wave signal perpendicularly incident to the sea bottom and the reflected signal and successively stored in a register 14 and the reflection coefficient of each layer forming transmission function is calculated on the basis of the time window of each layer of a register 9 corresponding to the thickness and acoustic velocity of each layer to be stored in registers 17, 20. A power series function is converted to a simple equation from the reflection coefficient while a damping coefficient operation apparatus 21 for performing least squares operation calculates the damping coefficient of each layer and a density operation apparatus 23 determines the density of each layer by also using reflection coefficients from the registers 17, 20. By this method, the characteristics of each sedimentary layer are accurately analyzed even when damping coefficient is not proportional to frequency but proportional to power series. |
