Propagación de ondas sísmicas en un asteroide

Abstract

During recent space missions targeting asteroids, artificial impacts have been planned and successfully performed. This allows to realistically discuss the ability to perform seismic experiments and obtain seismic records during future missions, which might very well be a reality during the next decade. A numerical simulation is performed using Axisem, an axisymmetric spectral elements code, to study the seismic response of a small asteroid. Two simple models are proposed in order to characterize the effects of a small regolith layer on wave propagation. Source and mesh parameters are scaled to achieve the required resolution and a realistic seismic response. Final data is extracted from both models in the form of wavefield snapshots and synthetic seismograms at a number of epicentral distances. The results show the regolith’s efficiency at guiding body waves and retaining seismic energy when no attenuation is considered. Regolith uplifting due to ground accelerations caused by Rayleigh waves is also shown to be possible by surpassing the asteroid’s microgravity. Obtaining seismic records from small active sources should also be feasible if the instrument is well attached to the surface, allowing for seismic probing and providing a new tool to access an asteroids interior.