Twenty-Thousand Leagues Under the Sea- Recording Earthquakes with Autonomous Floats

Abstract

Fifty Years Much like medical doctors who use X-rays or acoustic waves to make three-dimensional images of our insides, geophysicists use the elastic wavefield generated by earthquakes worldwide to scan the deep interior of our planet for subtle contrasts in the propagation speeds of seismic waves. To image the deep Earth using seismic tomography, over the years, seismologists have densely covered the continents with seismometers to measure ground motion. As with medical tomography, where sources and detectors are rotated all around to illuminate our bodies from all angles, achieving similarly evenly distributed geographical coverage for seismology requires making measurements all over the Earth surface, including the two-thirds that are covered by oceans. Yet, although some ocean islands do host geophysical observatories, gathering data over marine areas continues to present unique challenges.