Simulation of Seismic Wave Propagation on Asteroid Ryugu Induced by The Impact Experiment of The Hayabusa2 Mission: Limited Mass Transport by Low Yield Strength of Porous Regolith

Seismic shaking has been regarded as an essential source of resurfacing on asteroids. The Small Carry-on Impactor (SCI) operation Hayabusa2 expected to be a unique opportunity for testing in situ seismic whose energy is sufficiently large excite observable surface modification. However, no obvious regolith hopping was identified even immediately outside the crater formed by SCI impact. To understand this discrepancy from expectation, we simulate wave propagation Ryugu with wide range material properties and evaluate maximum acceleration surface. Numerical results reveal that low-quality factor or low efficiency required explain lack geomorphological change after experiment. Considering scattering under anhydrous conditions cannot efficiently dissipate energy, such not plausible. weak yield strength porous materials can decrease energies, making apparent extremely low. Based hypothesis, propose formulation mobility asteroids considers physical regolith. We consistently estimate occurrence existence unstable boulders Ryugu.