Aki was born in Yokohama, Japan. He received his bachelor's degree in 1952 and doctoral degree in 1958, both from the University of Tokyo. Until 1960, he conducted research at that university's Earthquake Research Institute. He then did post-doctoral research at the Caltech Seismological Laboratory, where he worked with Frank Press.[2]
Press invited Aki to join him at MIT in 1966. This second visit to the United States coincided with the 1966 Parkfield earthquake, noteworthy for its so-called coda waves, reverberations of seismic energy due to multiple scattering from subsurface inhomogeneities. Aki "developed a passion for using those waves to investigate Earth," according to Bill Ellsworth, Aki's former student who was later head of the USGS seismology group. "He came from Japan as a statistically oriented seismologist, but he was not afraid to transform himself."[2]
In 1995, Aki moved to the seismically active island Réunion, east of Madagascar in the Indian Ocean, where he continued to work until his death there in 2005.[3] He sustained an injury to his brain from a fall while walking in the street on May 13; he fell into a coma and died on May 17. He left behind two sons (Shota and Zenta) and two daughters (Kajika and Uka).
