Hiromichi Nagao has been an Associate Professor at Earthquake Research Institute, The University of Tokyo since 2013. He earned a Ph.D. in Science at Kyoto University in 2002, and then studied solid earth science at several postdoctoral positions. He is interested in applied mathematics and statistics beneficial to geoscience, especially data assimilation that integrates numerical simulations and observational data based on Bayesian statistics. Recently, he developed a new four-dimensional variational method for data assimilation using massive simulations and data, which achieves uncertainty quantification within practical computational time and resources.