Normal fault 3D geometry and displacement revisited: Insights from faults in the Norwegian Barents Sea

Abstract

Abstract Utilizing seismic attributes, we image fault 3D geometry for 21 normal faults of different sizes in the Norwegian Barents Sea. We revisit the published models of fault shape and growth using the new dataset. Based on the maximum accumulated length ( L m a x ) of faults, we have classified them into two classes: medium size (1 ≤ L m a x ≤ 1000 m ) and long faults ( L m a x > 1000 m ). The common characteristics of these faults are: i) the medium size faults show mainly irregular shapes while long faults show a variety of shapes including irregular, rectangular, and elliptical. ii) in medium size faults maximum displacement is located close to the fault upper tip-line. iii) no lateral segmentation was observed for most of the medium size faults while long faults contain several internal segments at each depth. iv) linkage with other faults is less common in medium size faults in comparison to the long ones. v) long faults with an elliptical shape have several displacement maxima located near the fault centre or close to the upper tip-line. vi) long faults with irregular to rectangular shapes show the displacement maxima close to either upper or lower fault tip-line. Our results show that for many of the analyzed faults, the maximum displacement is located on the faults longest segment; however, this is not the case for some of the faults. We found that power-law fits well with the displacement-length and displacement-height relations of the faults. Furthermore, the aspect ratio, the ratio between fault maximum accumulated length and height is high for the studied faults and ranges between ∼1.5 and ∼16. The results can shed light on the understanding of fault geometry and growth for a variety of applications including geological and mechanical models incorporating faults.