A new finite - difference method is developed for seismic modeling and reverse - time migration based upon the voronoi cell construction on irregular grids . curved velocity boundaries and irregular earth surface can be accurately represented using the irregular grid implementation . therefore the modeled and migrated results can be more accurate , and meanwhile , the efficiency is still preserved using an explicit finite - difference scheme 本文的方法可以實現任意非規則網格上的顯式差分計算,因此該方法在保持了傳統的矩形網格差分算法簡單、高效特點的同時,又能精確地描述彎曲界面和起伏地表,提高了有限差分地震模擬和偏移結果的精度。