Modeling the effect of static errors in areal seismic data caused by glacial erosion over carbonate reefs

Abstract

An effective way of exploring for structural features is by areal seismic methods. In addition to finding depth and location, the area of a structure may be determined at a reasonable cost. However, the efficacy of the areal method can be rapidly destroyed by static shifts in the seismic traces. In this paper we investigate the effect of statics on the crossed array method of areal data collection. Seismic data were collected in the northern Michigan reef trend, an area containing numerous small pinnacle reefs. The surface topography is flat, but it contains deep erosional valleys filled with glacial drift which produce time shifts in the data. The data were processed without static corrections. To predict the effect of static errors, a model was designed to produce data resembling those taken over a pinnacle reef. Seismic data were collected over this model by a method simulating the crossed array technique. Horizontal displays of the power envelope and the instantaneous phase of the migrated data were generated at a specified one‐way time, when various source and receiver dependent statics had been introduced into the raw data. The statics were designed to simulate the effect of glacial drift. If the diameter of the migration aperture is significantly larger than the distance along the source and receiver lines affected by statics, the effect on the migrated output is minimal. However, if the distance affected by statics approaches the diameter of the migration aperture, the effects are significant.