R/V Sikuliaq with seafloor transponders

Six orange seafloor transponders rest on the deck of research vessel Sikuliaq, which is owned by the National Science Foundation and operated by the University of Alaska Fairbanks. The transponders will be placed on the seafloor in the Cascadia subduction zone offshore Oregon and Washington. As they relay their positions to surface vessels or wavegliders, they will serve as benchmarks recording the relative motions of the tectonic plates on which they sit.