The Ocean's Seismic Hum

Abstract

Since the early 20th century, seismometers have detected a continuous, low-frequency seismic "hum" that is caused by wave-wave interactions in the ocean. In their Perspective, Kedar and Webb review advances reported at a recent meeting toward understanding the origins of this hum (which is referred to as ocean microseisms) and utilizing it in Earth science applications. For example, ocean microseisms can be used to assess El Niño conditions for times when few ocean data were available. They can also be used to monitor temporal changes in Earth's upper crust that cannot be detected with conventional seismology methods. Space- and airborne instruments may help to identify more clearly those regions where ocean microseisms are generated.