Abegunrin Ayobami, Hepp Daniel A, Mörz Tobias
MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
Geo-Engineering.org GmbH, Bremen, Germany.
Sci Rep. 2020 Oct 30;10(1):18760. doi: 10.1038/s41598-020-75740-z.
Variations in the physical properties of water column usually impede exact water column height correction on high-resolution seismic data, especially when the data are collected in shallow marine environments. Changes in water column properties can be attributed to variation in tides and currents, wind-generated swells, long and short amplitude wave-fronts, or variation in salinity and water temperature. Likewise, the proper motion of the vessel complicates the determinability of the water column height. This study provides a less time-consuming and precise differential Global Positioning System based methodology that can be applied to most types of high-resolution seismic data in order to significantly improve the tracking and quality of deduced geological interpretations on smaller depth scales. The methodology was tested on geophysical profiles obtained from the German sector of the North Sea. The focus here was to identify, distinguish and classify various sub-surface sedimentary structures in a stratigraphically highly complex shallow marine environment on decimeter small-scale. After applying the correction to the profiles, the sea floor, in general, occurs 1.1 to 3.4 m (mean of 2.2 m) deeper than the uncorrected profiles and is consistent with the sea floor from published tide corrected bathymetry data. The corrected seismic profiles were used in plotting the depth of the base of Holocene channel structures and to define their gradients. The applied correction methodology was also crucial in glacial and post-glacial valley features distinction, across profile correlation and establishing structural and stratigraphic framework of the study area.
水柱物理性质的变化通常会妨碍对高分辨率地震数据进行精确的水柱高度校正，尤其是在浅海环境中采集数据时。水柱性质的变化可归因于潮汐和洋流、风生涌浪、长短波幅波前的变化，或盐度和水温的变化。同样，船只的移动也会使水柱高度的可测定性变得复杂。本研究提供了一种基于差分全球定位系统的耗时较少且精确的方法，该方法可应用于大多数类型的高分辨率地震数据，以便在较小深度尺度上显著提高推导地质解释的追踪效果和质量。该方法在从北海德国海域获取的地球物理剖面进行了测试。这里的重点是在分米级小尺度上，在一个地层高度复杂的浅海环境中识别、区分和分类各种地下沉积构造。对剖面应用校正后，一般来说，海底比未校正的剖面深1.1至3.4米（平均2.2米），并且与已发表的经潮汐校正的测深数据中的海底一致。校正后的地震剖面用于绘制全新世河道构造底部的深度并确定其坡度。应用的校正方法在区分冰川和冰后期山谷特征、跨剖面对比以及建立研究区域的构造和地层框架方面也至关重要。
