The role of pre-existing discontinuities in the development of extensional faults: An analog modeling perspective

The Influence of Pre‐existing Basement Faults on the Cenozoic Structure and Evolution of the Proximal Domain, Northern South China Sea Rifted Margin

“…It has been well studied that the degree to which pre‐existing faults in a certain area can undergo reactivation largely depends on their orientations relative to the extension direction, though as was mentioned above the size, dip angle, and spacing of the pre‐existing faults may also exert a significant influence on the degree of reactivation (e.g., Bonini et al, , ; Corti et al, , ; Morley, ; Morley et al, ; Phillips et al, ; Reilly et al, ). Numerical and analog models suggested that under a given extension direction, large depocenters are predicted to form in pre‐existing weak zones mostly orthogonal to the extension direction, while smaller depocenters will form along the oblique weak zones (e.g., Corti et al, ).…”

“…Important for this paper, a recent study based on these high‐resolution 3D seismic data revealed a complex network of pre‐existing faults within the basement of the Cenozoic rift basin in the northern SCS margin (Ye, Mei, Shi, Camanni, et al, ). Therefore, how this region of the Cenozoic rift basin evolved to its current architecture needs to be reconsidered from the perspective of basement control since it is well known in rift basins worldwide that pre‐existing basement structure is a key factor in shaping the rift architecture and influencing the kinematic evolution of rifting (e.g., Autin et al, ; Bird et al, ; Bladon et al, ; Bonini et al, , ; Corti et al, ; Fazlikhani et al, ; Gibson et al, ; Katumwehe et al, ; Kharazizadeh et al, ; Manatschal et al, ; Phillips et al, ; Rotevatn et al, ).…”

Testing Different Tectonic Models for the Source of the Mw 6.5, 30 October 2016, Norcia Earthquake (Central Italy): A Youthful Normal Fault, or Negative Inversion of an Old Thrust?

“…If a weak layer located above a propagating fault causes its plane to be refracted (i.e., steepening for extensional faults and shallowing for reverse faults) and its characteristic propagation‐to‐slip ratio to be delayed, the role of a frictional weakness becomes more complex. Several investigators have explored this effect using analog and numerical models (e.g., Albertz & Sanz, ; Bonini et al, ; Bonini, Basili, et al, ; Bonanno et al, ; Hughes & Shaw, ; Roering et al, ).…”

“…For extensional faults, knowing that the frictional properties of the weak surface are critical, also, the relative orientation of the new and the existing structures plays a significant role (Bonini et al, ). For instance, a horizontal frictional surface ahead of the propagating tip of an extensional fault increases the propagation rate of new faults.…”

“…When the dip of existing frictional surfaces is ≥30°, these surfaces can be reused as extensional faults. As a result, all these different interactions also impact the magnitude of the fold‐related extensional faults (Bonini et al, ). Since our tectonic models are designed at a regional scale, we use these rules only for major frictional surfaces that coincide with existing faults, either contractional or extensional.…”