Nishida Prize

Miaki Ishii


Research on seismological structure of the core, mantle, and crust and studies of nature of earthquake ruptures

A list of five major papers

  • Ishii, M., & Tromp, J., 1999. Normal-mode and free-air gravity constraints on lateral variations in velocity and density of the Earth’s mantle. Science 285, 1231–1236.
  • Ishii, M., & Dziewónski, A.M., 2002. The innermost inner core of the earth: Evidence for a change in anisotropic behavior at the radius of about 300 km. Proc. Natl. Acad. Sci. USA 22, 14026–14030.
  • Ishii, M., Shearer, P.M., Houston, H., & Vidale, J.E., 2005. Extent, duration and speed of the 2004 Sumatra-Andaman earthquake imaged by the Hi-Net array. Nature 435(7044), 933–936.
  • Ishii, M., Kiser, E., & Geist, E.L., 2013. Mw 8.6 Sumatran earthquake of April 11, 2012: Rare seaward expression of oblique subduction. Geology 41(3), 319–322.
  • Park, S., & Ishii, M., 2018. Near-surface compressional and shear wave speeds constrained by body-wave polarization analysis. Geophys. J. Int. 213(3), 1559–1571.

Major achievements

Miaki Ishii developed an epoch-making method of analyzing seismic data, and contributed to seismology and geophysics by clarifying the structure and dynamics of the earth’s inner core, mantle, and crust. In particular, the development and application of the back-projection method for imaging high-frequency seismic sources using a large-scale dense seismic network has advanced our understanding of the detailed rupture process of giant earthquakes including the 2004 Indian Ocean and 2011 Tohoku-Oki earthquake. This method is now widely used as one of the standard analytical methods of seismology. She also made important and pioneering discoveries which led to the elucidation of the dynamics of the earth’s interior such as the existence of large-scale density anomaly in the lowermost mantle and the change of anisotropy in the deepest part of the inner core. In recent years, she has been involved in outreach activities with high school students in Japan to digitize old earthquake records. Her achievements have greatly advanced understanding of solid earth and large-scale earthquake properties and have been highly recognized internationally.


William F. McDonough