Shaking Without Quaking

The idea that Earth can ring like a bell was proposed more than 80 years ago; since then, geoscientists have debated what mechanisms can set Earth ringing. In his Research Commentary, Kanamori discusses recent research, including a research report in the same issue by Suda et al ., showing that these free oscillations can be driven by both earthquakes and nonearthquake forces such as atmospheric disturbances.