Fault Trace Corrugation and Segmentation as a Measure of Fault Structural Maturity

Abstract

Faults are growing features: over geological time, generally, several Myrs, if submitted to tectonic stresses, a fault grows by accumulating slip and lengthening along-strike (e.g., Fossen & Rotevatn, 2016;Manighetti et al., 2001). Generally, the growth occurs through repeated earthquake ruptures. "Structural maturity" is a term coined to describe qualitatively the slip longevity of a fault; the longer the slip history, the more mature the fault. Although the concept appeared in early works (

Earthquake Cycle Deformation Associated With the 2021 MW 7.4 Maduo (Eastern Tibet) Earthquake: An Intrablock Rupture Event on a Slow‐Slipping Fault From Sentinel‐1 InSAR and Teleseismic Data

“…By contrast, earthquakes with high rupture velocities are typically related to well‐developed faults (Perrin et al., 2016), such as the 2001 M W 7.8 Kokoxili earthquake and the 2002 M W 7.9 Denali earthquake (Ozacar & Beck, 2004; Walker & Shearer, 2009) as well as the 2018 M W 7.5 Palu earthquake (Bao et al., 2019; Socquet et al., 2019), all of which have occurred on major block boundaries. While mature faults appear to be geometrically simpler, shear zones in the initial stage of faulting have generally more complex geometries with fault segmentations and variable disorganized orientations (Crider & Peacock, 2004); as faults grow and develop through time, the fault segments tend to localize deformation and evolve from being hardly linked to fully linked; new step‐overs may be created with the pre‐existing ones smoothed out, leading to a more continuous and through‐going fault trace with lower strength and lower fracture energy as the fault becomes more mature (Ben‐Zion & Sammis, 2003; Manighetti et al., 2007, 2021; Wesnousky, 1988). These facilitate hosting strong earthquakes at fast speed (Manighetti et al., 2007; Perrin et al., 2016).…”

“…This raises the following key questions regarding earthquakes that occur in block interiors: What is the hazard from earthquakes in block interiors? Do earthquakes behave differently in continental interiors because of the relative structural immaturity of seismogenic faults, where the term structural maturity is used to describe the slip longevity of a fault (e.g., Manighetti et al, 2007Manighetti et al, , 2021Perrin et al, 2016;Radiguet et al, 2009)? If Global Navigation Satellite System (GNSS) data are sparse, can Interferometric Synthetic Aperture Radar (InSAR) illuminate strain away from the main faults?…”

Imprint of the Continental Strike‐Slip Fault Geometrical Structure in Geophysical Data

“…Analogue model experiments (Lefevre et al, 2020) as well as numerical models (Jiao et al, 2021) were used to test further this assumption and to demonstrate that a linear relation between the average lateral extent of fault structures and the thickness of the brittle material is observed for a wide range of thickness and that such relation seems to hold beyond only geomaterials (Cambonie et al, 2019). Thus, Chu et al (2021) add to a set of independent observations that points to the existence of a permanent specific scaling of the strike slip fault segments consistent with the thickness of the crust (Figure 1), and likely independent of the fault maturity (Manighetti et al, 2021).…”

“…Thus, Chu et al. (2021) add to a set of independent observations that points to the existence of a permanent specific scaling of the strike slip fault segments consistent with the thickness of the crust (Figure 1), and likely independent of the fault maturity (Manighetti et al., 2021).…”

Precursory Off‐Fault Deformation in Restraining and Releasing Step Overs: Insights From Discrete Element Method Models

“…In addition, because fault networks evolve from isolated smaller segments to connected, larger, through‐going faults (e.g., Ben‐Zion & Sammis, 2003; Manighetti et al., 2007; Otsuki & Dilov, 2005), testing the influence of increasing the separation distance enables systematic comparison of the influence of structural maturity on the style and location of precursors. Comparison of km‐scale seismogenic fault networks indicates that the ratio of the maximum width of a step over to the segment length within crustal fault networks decreases with increasing maturity (Manighetti et al., 2021). Consequently, fault networks with smaller separation distance represent more structurally mature fault systems with greater localization than more immature systems that tend to have larger offsets between the fault segments.…”