Dependence of scale and fault type on the relationship between fault lengths and displacements

The characteristics of fault geometries and the relationship between fault lengths and displacements are important for understanding the fault growth mechanism. Thus, many previous studies have been conducted to analyze several fault factors (e.g. fault length, displacement, fault core thickness, and fault damage zone width). It has generally been accepted that the relationship between fault lengths and displacements, based on global datasets across various scales, is expressed as a power-law. However, some researchers argued that the ratio between fault lengths and displacements does not increase constantly, and established new fault growth models (e.g. fault linkage model, and constant-length model). In this study, we reexamined global datasets obtained in previous studies associated with fault lengths and displacements to understand the dependence of scale, and fault type on the fault length-displacement relationship.

The fault length (L, x-axis) and displacement (D, y-axis) data (D/L) on the log-log plot, shows slop change getting steep from low ratio on small scale to high ratio on large scale, indicating different fault growth mechanisms. Also, based on the data plots in terms of different fault types, we recognize the dependence of fault types. The graph for strike-slip faults shows an almost constant slop regardless of scale, while the graphs for dip-slip faults (normal faults and thrust faults) show similar patterns (i.e. changing with scale). These characteristics of the distribution of fault length-displacement suggest that the relationship depends on fault scale and type. This may be due to the direction of fault propagation to length. For example, strike-slip faults propagate parallel to the fault lengths, but dip-slip faults propagate perpendicular to fault lengths. This study on the fault length-displacement relationship can improve our understanding of fault growth mechanisms and their controlling factors.

Acknowledgements

This work was supported by the Institute for Korea Spent Nuclear Fuel (iKSNF) and National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science and ICT, MSIT) (No. 2021M2E1A1085200).