Shock wave propagation in layered planetary interiors: Revisited

Co-auteur étrangerInternational audienceWhile major impacts during late accretion of a Mars type planet occur on a differentiated body, the characteristics of the shockwave propagation are poorly knownwithin these layered objects. Here, we use iSALE-2D hydrocode simulations to calculate shock pressure in a differentiated Mars type body for impact velocitiesranging from 5 to 20 km/s, impactor radii ranging from 50 to 200 km, and different rheologies. To better represent the distribution of shock pressure as a function ofdistance from the impact site at the surface, we propose two distinct regions in the mantle: a near field region that extends to 7–15 times the projectile radius into thetarget, where the peak shock pressure decays exponentially with increasing the distance from the impact site, and a far field region where the pressure decaysstrongly with the distance following a power law. At the core-mantle boundary, the peak shock pressure increases from the mantle side to the core side. The refractedshockwave travels within the core where the shock pressure decreases following a second power law. In this study, we fit the output obtained from iSALE hydrocodesimulations to determine scaling laws that illustrate the influence of the distance from the impact site, the ray angle, the target rheology, the impactor size and theimpact velocity. Finally we combine these shock-pressure scaling laws with the formalism proposed by Watters et al. [2009] to determine the impact heating inducedby large impacts within a differentiated Mar