Sam Mitchell

Solid Earth Dynamics

BBK

UCL

Subsurface processes govern the deformation style of active faults and interaction between these faults control both the timings and lateral extent of hazardous earthquake shaking. In order to better analyse a fault’s seismic activity, these underlying processes need to be better understood. Constraints on the subsurface processes can be gained by studying the long-term (multiple millennia) slip-rates associated with well-exposed faults in central Greece. Slip rates can be calculated using field fault measurements of displacement and from observations of offset tectonic geomorphology whose age is well constrained. The slip rates can be converted into strain-rates if mapped regionally, and strain rates can then be analysed spatially to understand how faults react to stress loading produced by topographic variations, and elastic and viscous shear-zone interactions. The strain rates are compared to topographic elevation data to constrain the spatial variations in body forces that produce stresses. These body forces influence the activity rates on the viscous/shear zones that potentially govern the earthquake activity in tectonically active regions. The findings in central Greece can be compared with existing short-term strain-rates to evaluate how the regional driving forces, age, and localisation of the faults affect the present-day fault behaviour.

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