地下地層常因受到大地應力系統作用及岩石結晶演化特性之差異而導致破裂帶產生，此地層之破裂現象常造成地層岩性非均向之物理特性，使得震波在傳播時造成震波走時差異與振幅的異常。本研究利用可控制實驗參數之三維物理模型，以超音波穿透技術量測震波受地層非均向性因素影響造成之速度變化做系列分析、研究，並由已知岩層內部構造下所量測得之震波特性資料，進而比對應用於實際野外量測工作。 本實驗結果顯示，無論非均向介質於乾燥或飽和流體之情況下，震波波速均會隨測線與具方向性排列裂隙之夾角改變而有顯著的變化。根據此震波特性，應用於野外震波探測時，設計往不同方向施展測線，藉由測線與具方向性排列裂隙之夾角改變而造成S波波速產生變化之特性，可迅速確切地推斷出裂隙排列之大致走向與分布情形。 Effects on wave propagation caused by the influence of cracks in the substrata resulted from the stress system and/or crystalline characteristics are an important topic for oil exploration. Depending upon the crack or fracture pattern in rocks, it results in an velocity anisotropy, wave trapping and splitting. This study aimed at the analysis of effects of cracks on the wave characters such as velocity changing related to the intersection angle between seismic profile and rock’s crack alignment. The effects of porosity, formation fluids and density and geometry distribution of cracks on wave propagation have been also investigated. Based on the results, it implies that the velocity measurement on the seismic events by surface seismic profile is a probable approach to estimate the anisotropy in substratum.
