Previous studies suggest other possible mechanisms for the lunar farside-nearside dichotomy. The ejecta blanket thicknesses are comparable to the difference between nearside and farside crustal thickness. In these simulations, an ejecta blanket forms, with a thickness of kilometers, over the lunar farside. I calculate the trajectory of ejecta that leave the crater and return to the lunar surface. I use iSALE, an impact hydrocode, to determine the ejecta distribution, volume, and thickness. Ejecta blankets depend on impactor size and angle. During the impact process, ejecta leave the crater and travel well beyond the transient crater. Here I suggest that large impacts eject enough material to cover the farside of the Moon. The largest known impact on the Moon formed the South Pole-Aitken (SP-A) basin and excavated material as deep as the mantle. My results thus support the idea that iron in the cores of even large differentiated planetesimals can chemically equilibrate deep in a terrestrial magma ocean. The impact dispersed core fragments undergo further mixing through turbulent entrainment as the molten iron fragments sink through the magma ocean and settle deeper into the planet. The statistics of stretching imply mixing that separates the iron core into sheets, ligaments, and smaller fragments, on a scale of 10 km or less. The final displacement distance of initially closest tracer pairs gives a metric of core stretching. Lagrangian tracer particles track the initially intact iron core as the impact stretches and disperses the core. The impact process strips away the silicate mantle of the planetesimal and then stretches the iron core, dispersing the liquid iron into a much larger volume of the underlying liquid silicate mantle. I have performed hydrocode simulations that revise this assumption and yield a clearer picture of the impact process for differentiated planetesimals possessing iron cores with radius = 100 km that impact into magma oceans. Recent studies of differentiated planetesimal impacts assume that planetesimal cores survive the impact intact as concentrated masses that passively settle from a zero initial velocity and undergo turbulent entrainment in a global magma ocean under these conditions, cores greater than 10 km in diameter do not fully mix without a sufficiently deep magma ocean. We study the mega‐tsunami runup with a hybrid modeling approach applying physical and numerical models of slide processes of deformable bodies into a U‐shaped trench similar to the geometry found at Lituya Bay.The abundance of moderately siderophile elements (“iron-loving” e.g., Co, Ni) in the Earth’s mantle is 10 to 100 times larger than predicted by chemical equilibrium between silicate melt and iron at low pressure, but it does match expectation for equilibrium at high pressure and temperature. While these observations have not been challenged directly, they have been largely ignored in hazard mitigation studies, because of the difficulties of even posing – much less solving – a well‐defined physical problem for investigation. A forest trim line and erosion down to bedrock mark the largest runup in recorded history. The rockslide impact generated a giant tsunami at the head of Lituya Bay resulting in an unprecedented tsunami runup of 524 m on a spur ridge in direct prolongation of the slide axis. The largest mega‐tsunami dates back half a century to 10 July 1958, when almost unnoticed by the general public, an earthquake of Mw 8.3 at the Fairweather Fault triggered a rockslide into Lituya Bay. Hybrid modeling of the mega‐tsunami runup in Lituya Bay after half a century Hybrid modeling of the mega‐tsunami runup in Lituya Bay after half a century
0 kommentar(er)
