Two large quakes sensed in the stratosphere by pressure sensors on board Strateole-2 balloons

The ground movements induced by seismic waves create acoustic waves propagating upward in the atmosphere, thus providing a practical solution to perform remote sensing of planetary interiors. However, a terrestrial demonstration of a seismic network based on balloon-carried pressure sensors has not been provided. Here we present the first detection of seismic infrasound from a large magnitude quake on a balloon network. We demonstrate that quakes properties and planet internal structure can be probed only from balloon-borne pressure records because these are generated by the ground movements at the planet surface below the balloon. Various seismic waves are identified, thus allowing us to infer the quake magnitude and location, as well as planet internal structure.The mechanical resonances of balloon system are also observed. This study demonstrates the interest of planetary geophysical mission concepts based on seismic remote sensing with balloon platforms, and their interest to complement terrestrial seismic networks.The balloon response to infrasound waves is also modeled, and the application to Phantom Venus mission project (NASA New Frontiers 5) is described.