Toshiro Tanimoto

I am a geophysicist/seismologist, specializing in seismic wave propagation and oscillations of the Earth. I used this skill to study the interior structure of the Earth for the first 15 years of my research career. My aim was to understand mantle convection, whose surface manifestation is the plate tectonics. By mapping seismic speeds and anisotropy in the mantle, I dreamed of mapping mantle flow and made some progress, especially in developing various approaches for analyzing seismic waves.

Around 1997, with Naoki Kobayashi and Kiwamu Nishida, we discovered that Earth was undergoing continuous oscillations for periods between about 100 sec and 300 sec, even when earthquakes were not happening. We called them “the background oscillations” but they are now commonly referred to as “the hum”. After this work, I became more interested in understanding noises in seismograms that were caused by ocean waves, atmospheric winds, and other environmental effects.

I plan to use the opportunity afforded by the Guggenheim Fellowship to study seasonal changes in shallow structure in the Arctic zone. In polar regions, strong seasonal changes occur at shallow depths because of thawing of ice. I am keen on understanding how global warming is manifested in such seasonal changes.