Imperial College London

MissSophie WenjiaoPan

Faculty of EngineeringDepartment of Earth Science & Engineering

Casual - Student demonstrator - lower rate
 
 
 
//

Contact

 

sophie.pan16

 
 
//

Location

 

3.49HRoyal School of MinesSouth Kensington Campus

//

Summary

 

Publications

Publication Type
Year
to

5 results found

Pan S, Naliboff J, Bell R, Jackson Cet al., 2022, Kinematic and rheological controls on rift-related fault evolution

<jats:p>Continental extension is primarily accommodated by the evolution of normal fault networks. Rifts are shaped by complex tectonic processes and it has historically been difficult to determine the key rift controls using only observations from natural rifts. Here, we use 3D thermo-mechanical, high-resolution (&lt;650 m) forward models of continental extension to investigate how fault network patterns vary as a function of key rift parameters, including extension rate, the magnitude of strain weakening, and the distribution and magnitude of initial crustal damage. We quantitatively compare modelled fault networks with observations of fault patterns in natural rift, finding key similarities in their along-strike variability and scaling distributions. We show that fault-accommodated strain summed across the entire 160 x 160 km study area increases linearly with time. We find that large faults do not abide by power-law scaling as they are limited by an upper finite characteristic, ω0. Fault weakening, and the spatial distribution of initial plastic strain blocks, exert a key control on fault characteristics. We show that off-fault (i.e. non-fault extracted) deformation accounts for 30-70% of the total extensional strain, depending on the rift parameters. As fault population statistics produce distinct characteristics for our investigated rift parameters, further numerical and observational data may enable the future reconstruction of key rifting parameters through observational data alone.</jats:p>

Journal article

Pan SW-J, 2022, Understanding fault evolution using numerical models and seismic data observations

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

Thesis dissertation

Pan S, Naliboff J, Bell R, Jackson Cet al., 2022, Bridging spatiotemporal scales of normal fault growth during continental extension using high-resolution 3D numerical models, G3: Geochemistry, Geophysics, Geosystems: an electronic journal of the earth sciences, Vol: 23, Pages: 1-16, ISSN: 1525-2027

Continental extension is accommodated by the development of kilometer-scale normal faults, which grow during meter-scale slip events that occur over millions of years. However, reconstructing the entire lifespan of a fault remains challenging due to a lack of observational data with spatiotemporal scales that span the early stage (<106 yrs) of fault growth. Using three-dimensional numerical simulations of continental extension and novel methods for extracting the locations of faults, we quantitatively examine the key factors controlling the growth of rift-scale fault networks over 104–106 yrs. Early formed faults (<100 kyrs from initiation) exhibit scaling ratios consistent with those characterizing individual earthquake ruptures, before evolving to be geometrically and kinematically similar to more mature structures developed in natural fault networks. Whereas finite fault lengths are rapidly established (<100 kyrs), active deformation is transient, migrating both along- and across-strike. Competing stress interactions determine the distribution of active strain, which oscillates between being distributed and localized. Higher rates of extension (10 mm yr−1) lead to more prominent stress redistributions through time, promoting episodic localized slip events. Our findings demonstrate that normal fault growth and the related occurrence of cumulative slip is more complex than that currently inferred from displacement patterns on now-inactive structures, which only provide a space- and time-averaged picture of fault kinematics and related seismic hazard.

Journal article

Pan S, Bell RE, Jackson CA-L, Naliboff Jet al., 2021, Evolution of normal fault displacement and length as continental lithosphere stretches, Basin Research, Vol: 34, Pages: 121-140, ISSN: 0950-091X

Continental rifting is accommodated by the development of normal fault networks. Fault growth patterns control their related seismic hazards, and the tectonostratigraphic evolution and resource and CO2 storage potential of rifts. Our understanding of fault evolution is largely derived by observing the final geometry and displacement (D)-length (L) characteristics of active and inactive fault arrays, and by subsequently inferring their kinematics. We can rarely determine how these geometric properties change through time, and how the growth of individual fault arrays relate to the temporal evolution of their host networks. Here we use 3D seismic reflection and borehole data from the Exmouth Plateau, NW Shelf, Australia to determine the growth of rift-related, crustal-scale fault arrays and networks over geological timescales (>106 Ma). The excellent-quality seismic data allows us to reconstruct the entire Jurassic-to-Early Cretaceous fault network over a relatively large area (ca. 1,200 km2). We find that fault trace lengths were established early, within the first ca. 7.2 Myr of rifting, and that along-strike migration of throw maxima towards the centre of individual fault arrays occurred after ca. 28.5 Myr of rifting. Faults located in stress shadows become inactive and appear under-displaced relative to adjacent larger faults, onto which strain localises as rifting proceeds. This implies that the scatter frequently observed in D-L plots can simply reflect fault growth and network maturity. We show that by studying complete rift-related normal networks, rather than just individual fault arrays, we can better understand how faults grow and more generally how continental lithosphere deforms as it stretches.

Journal article

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wlsprd.imperial.ac.uk:80/respub/WEB-INF/jsp/search-html.jsp Request URI: /respub/WEB-INF/jsp/search-html.jsp Query String: respub-action=search.html&id=00730894&limit=30&person=true