Scaling laws of impact induced shock pressure and particle velocity in planetary mantle

• Published in: Icarus (New York, N.Y. 1962) Vol. 264; pp. 246 - 256
• Main Authors: Monteux, J., Arkani-Hamed, J.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.01.2016; Elsevier
• Subjects: Accretion; Decomposition; Earth Sciences; Heating; Impact processes; Impactors; Interiors; Mars; Mars surface; Planetology; Projectiles; Scaling laws; Sciences of the Universe; Terrestrial planets; Thermal histories; A, Mid-Atlantic Ridge; Impact processes; Terrestrial planets; Interiors; Accretion; Thermal histories
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2015.09.040

•Used hydrocode simulations to monitor shock wave propagation in a Mars type body.•Derived scaling laws of shock pressure and particle velocity versus distance.•100–400km diameter impactors with 4–10km/s impact velocities are investigated.•Using our power law distributions, we identify three regions from the impact site.•The scaling law parameters are impact velocity dependent. While major impacting bodies during accretion of a Mars type planet have very low velocities (<10km/s), the characteristics of the shockwave propagation and, hence, the derived scaling laws are poorly known for these low velocity impacts. Here, we use iSALE-2D hydrocode simulations to calculate shock pressure and particle velocity in a Mars type body for impact velocities ranging from 4 to 10km/s. Large impactors of 100–400km in diameter, comparable to those impacted on Mars and created giant impact basins, are examined. To better represent the power law distribution of shock pressure and particle velocity as functions of distance from the impact site at the surface, we propose three distinct regions in the mantle: a near field regime, which extends to 1–3 times the projectile radius into the target, where the peak shock pressure and particle velocity decay very slowly with increasing distance, a mid field region, which extends to ∼4.5 times the impactor radius, where the pressure and particle velocity decay exponentially but moderately, and a more distant far field region where the pressure and particle velocity decay strongly with distance. These scaling laws are useful to determine impact heating of a growing proto-planet by numerous accreting bodies.