准噶尔盆地南缘山前带表层结构调查及静校正

Near-surface Structure Survey and Static Correction Method of Thrust Belt at the Southern Edge of Zhunger Basin

准噶尔盆地南缘米泉地区地处复杂的逆冲断裂带,不仅地表高差变化大、断裂发育、老地层出露,而且表层岩性横向变化大,加上因风化、垮塌、冲积等原因在表层堆积厚度横向变化不等的黄土砾石,致使该区地震资料信噪比低、静校正复杂、地震资料成像困难。为此,从研究表层结构调查与地震成像之间的关系入手,提出了运用层析进行表层结构调查的方法,弥补了常规表层结构调查方法的观测盲区,提高了表层结构模型的精度,并结合层析静校正方法提高了地震成像效果。

Miquan area, which is at the southern edge of Zhunger Basin, is located in a complex thrust belt. In this area, static correction is very complex and signal--to--noise ratio is low because of height difference of terrain, frequent variation of lithology, many faults and outcrop of old layer. What＇s more, the loess and gravel with differenet thickness built up on the surface by weathering, collapse and altuviation influence the mapping of the seismic information in this area. Therefore, the authors, beginning with studying the relationship between near--surface structure survey and seismic imaging, present an application of tomography method in near--surface structure survey of thick loess and gravel areas, which resolves the observation difficulties of general field near--surface survey method and increases the accuracy of field near--surface modeling. Also, they probe into further improving seismic imaging through static correction in accordance with the tomographic static correction method.