| Περιγραφή: |
Faults form in response to continental extension and are ubiquitous in the Earth’s lithosphere. Our current understanding of normal fault growth is largely derived from geometrical observations of these structures in the Earth’s crust, in particular utilising the relationship between fault length (L) and maximum displacement (D). However, our understanding of the kinematics and timescales of fault growth is relatively poor, as many faults are not associated with age- constrained growth strata that record the timing of fault activity. This has subsequently led to the proposition of different, debated fault growth models. Inheritance, rheology, extension rates and rift obliquity also control rift geometry and kinematics, although it is unclear how these controls work in combination to form their final fault geometry. In this thesis, I investigate the geometric, kinematic, and dynamic relationships of normal faults, using borehole-constrained seismic reflectivity data, and high-resolution 3D forward numerical modelling. First, I constrain the geometrical and kinematic development of a fault network on the Exmouth Plateau, NW of Australia and find that faults establish their near-final lengths within the first 7.2 Myrs. I find that the magnitude of D-L scatter reflects fault maturity, with minor inactive faults exhibiting lower D-L ratios than larger, mature faults. Using numerical models, I also show that fault patterns are established early during rifting, within <100 kyrs of rift initiation, with individual faults exhibiting scaling ratios consistent with those characterising individual earthquake ruptures. With time, these faults growth to exhibit D-L ratios similar to those observed within global D-L datasets. Using these models I show that the behaviour of strain accumulation is highly transient, migrating along- and across- strike due to competing stress interactions. The distribution of strain accommodated by the fault network is best described by a gamma scaling law, indicating that small to moderate ... |