Fault growth on earthquake and geological timescales

Duration: 2007 – 2009

Funding: Embark Post-Doctoral Fellowship to Vasso Mouslopoulou

Basic Aims
The earth’s crust is broken up by faults which grow over millions of years due to repeated catastrophic earthquakes. Precisely how displacements during individual earthquakes sum to produce final patterns of faulting is poorly understood. To address this question we will chart the fault displacement accumulation on individual faults over timescales of thousands (short timescale) to millions (long timescale) of years in order to identify the principal factors that control the nature of fault growth. Specifically, we will examine issues such as: 1) To what extent short and long term displacement rates of active faults are comparable or are systematically related; 2) How interactions between faults of different sizes and densities influence the growth of individual faults; 3) Whether the stability of earthquake recurrence and size is controlled by fault size or fault type. Our objectives will be accomplished by compiling and analysing a worldwide database of active faults for which both short and long term displacements are available. Analysis of these data will allow us to reconstruct changes in fault displacement over a range of timescales and to produce more robust models for fault growth. The resulting models will therefore advance our knowledge of how faults evolve due to repeated earthquakes and will provide an improved basis for earthquake risking, both of which are research objectives which are of international significance.

More info at: https://www.fault-analysis-group.ucd.ie/

Relevant Publications:

Mouslopoulou, V., Walsh, J.J., Nicol, A., 2009. Fault displacement rates on a range of timescales. Earth and Planetary Science Letters 278, 186-197, https://doi.org/10.1016/j.epsl.2008.11.031.

Nicol, A., Walsh, J.J., Mouslopoulou, V., Villamor, P., 2009. Earthquake histories and Holocene acceleration of fault displacement rates. Geology 37, 911–914, https://doi.org/10.1130/G25765A.1

Townsend, D., Nicol, A., Mouslopoulou, V., Begg, J.G., Beetham, R.D., Clark, D., Giba, M., Heron, D., Lukovic, B., McPherson, A., Seebeck, H., Walsh, J.J., 2010. Paleoearthquake histories across a normal fault system in the southwestern Taranaki Peninsula, New Zealand. New Zealand Journal of Geology and Geophysics, 53, 4, 375-394, https://www.tandfonline.com/doi/full/10.1080/00288306.2010.526547.

Mouslopoulou, V., Nicol, A., Walsh, J.J., Begg, J.G., Townsend, D.B., Hristopulos, D.T., 2012. Fault-slip accumulation in an active rift over thousands to millions of years and the importance of paleoearthquake sampling. Journal of Structural Geology 36, 71-80, https://doi.org/10.1016/j.jsg.2011.11.010