Assessing seismic hazards in slowly deforming orogens | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Assessing seismic hazards in slowly deforming orogens

SLOWDEF
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Convergent plate boundaries are the loci of destructive earthquakes, such as along subduction zones or within the Himalayas where fast convergence rates and frequent large earthquakes have attracted numerous studies in the past. The seismic behavior of active faults is to the first-order reasonably well understood in these fast settings. Unfortunately, such is not the case of active faults within orogens where convergence rates are slow (< 5 mm/yr), so that assessing seismic hazards in these particular contexts remains a scientific and societal challenge. Taking up this challenge requires developing a new approach and strategy to unravel active deformation and elastic strain storage prior to earthquakes, as an alternative to interseismic deformation directly retrieved from classical geodetic techniques.

 

Rather than starting from short-term modern interseismic deformation rates as classically done, we propose to investigate active deformation first from a long-term perspective - ie over a time scale sufficient to cumulate observable and measurable deformation - and to progressively downscale to intermediate and then short-term active deformation. The proposed strategy to solve for active tectonics and associated seismic hazards in slowly deforming orogens therefore relies on the tight synthesis of geological data retrieved over various - but complementary - spatial and temporal scales. These data will be acquired using state-of-the-art tools and techniques of the Earth Sciences (structural geology, geomorphology, geodesy, mineralogy...). The originality and contribution of this project is their specific combination and integration for the particular purpose of assessing active tectonics in slowly deforming regions. The four main young researchers involved in the project are experts in each one of these various domains of the Earth Sciences, and their synergy will be ensured in a voluntarily designed limited research group coordinated by the PI.