The impact of erosion and sediment deposition on the initiation and evolution of faults: an investigation using fully coupled three-dimensional numerical models
Final Report Abstract
This research project investigated the impact of erosion and sediment deposition on the evolution of faulting in extensional and contracting regimes as well as the evolution of the respective landscapes. The investigation was based on fully coupled three-dimensional numerical models accommodated in the Abaqus software suite and the surface processes were implemented by using CASQUS, a set of routines that simulate landscape evolution. The modeling results have shown that erosion and deposition not only influence the slip rates of isolated normal faults during tectonic extension but can also prolong fault activity when the far field extension ceases. Single normal faults can continue accumulating tens of meters of slip for time spans of more than 1 Ma after the far field extension has ceased. The slip rate and the duration of fault activity in such phases depends on fault geometry (dip angle and length) and the the intensity of surface processes (slope diffusion processes). At the bottom line the interplay between fault geometry, tectonic stresses and the mass redistribution due to erosion and deposition on the earths surface controlled the differential stresses that induce fault displacement. These findings have implications when constraining tectonic phases, syn-sedimentary tectonics, spatiotemporal fault activity and earthquake hazards. Within en echelon fault arrays that form horst structures erosion and deposition have more complex controls on the temporal and spatial distribution of fault slip. In general, faults exhibit higher slip rates in models were surface processes are active the than in models without surface processes. When surface processes are present the normal faults that receive increased amounts of sediments on their hanging wall due to their position within the fault array exhibit higher slip rate increase that neighboring fault with relatively low sedimentation on their hanging walls. The amount of sediments depositing on different hanging walls not only governs which fault will experience increased slip withing a fault array. Local variations of sediment load within a single hanging wall basin induces local asymmetries on the distribution of fault slip along the fault trace. Such effects of the mass redistribution due to erosion and deposition in such tectonic settings continue to induce and influence fault slip behavior also when far field extension stops. In contractional tectonic regimes, the slip rates of small scale blind thrust faults with a fault top edge of 1 km or 2 km bellow the earth's surface are not influenced by erosion and deposition according to results of the present research project. However, the same results show that the fault slip rates of blind thrusts are directly influenced by the depth of their top edge. The form of the fault propagation folding taking place above the blind thrust also depends on the depth of the fault top edge and together with the surface processes it shapes the landscape that evolves during contraction.
Publications
- (2011) Response of active faults within fault arrays in extensional tectonic settings to mass redistribution on Earth’s surface due to erosion and sedimentation. Geophysical Research Abstracts Vol. 13, EGU2011-4120, EGU General Assembly, Vienna
Maniatis, G.,Turpeinen, H. and Hampel, A.
- (2011) The effect of erosion and sediment deposition on the slip evolution of normal faults after cessation of far-field extension, Geophysical Research Abstracts Vol. 13, EGU2011-3657, EGU General Assembly, Vienna
Turpeinen, H., Maniatis, G. and Hampel, A.
- (2012) Investigating the response of faults to mass redistribution due to erosion and sedimentation by using fully coupled 3D finite-element models with landscape evolution tool. 3rd Geoqus Conference 2012, Potsdam
Turpeinen, H., Maniatis, G. and Hampel, A.
- (2014) The effects of mass redistribution due to erosion and sedimentation on the distribution of fault activity within extensional fault arrays : An investigattion by using fully coupled 3D finite-element models with a landscape evolution tool. Geophysical Research Abstracts Vol. 16, EGU2014-4141, EGU General Assembly, Vienna
Maniatis, G.,Turpeinen, H. and Hampel, A.
- Slip on normal faults induced by surface processes after the cessation of regional extension - Insights from three-dimensional numerical modelling, Geomorphology (2014)
Turpeinen, H., Maniatis, G., Hampel, A.
(See online at https://doi.org/10.1016/j.geomorph.2013.12.008)
