湘鄂西山地双复杂介质条件下的静校正技术研究

On Correction Technology under the Double-complex Conditions in Mountainous Area between Western Hubei and Hunan

湘鄂西地区具有表层结构复杂多变、深部逆掩推覆构造特征强烈的双重复杂性,该区地形起伏剧烈,多种表层结构类型交替出现,野外静校正问题非常突出。TOMODEL层析静校正是一种非线性反演技术,利用地震波初至时间和射线路径反演出近地表速度模型,然后求取静校正量值,从而消除静校正影响。采用初至互换差属性和建立合理的高速顶顶界面的方法有效提高了层析反演的近地表速度模型精度,使最终的静校正量值更为合理,进一步提高了地震剖面的成像精度。

The double complex conditions of Western Hubei and Hunan are complex surface structure and complex deep overthrust nappe structure. The terrain changes strongly and various surface structures appear alternately, so the static correction is a key problem. TOMODEL tomographic static correction is a kind of nonlinear inversion technique, using seismic first break time and ray path to do the inversion of near--sur- face velocity modeling, and then calculate the static correction values, thereby eliminating static correction influence. First--break swap difference properties and reasonable high--velocity layer interface establish- ment effectively improve the precision of near--surface velocity model for tomographic inversion, make a final more reasonable static correction values, and further improve the seismic imaging precision.