Omori studied physics with the initial British foreign advisors serving as professors at the Imperial University of Tokyo, especially John Milne until he left Japan in 1895, as well as Japanese colleagues including Seikei Sekiya who in 1880 became the first professor of seismology at any university in the world at Tokyo Imperial University.
Omori Fusakichi visited foreign countries more than 10 times, including inspection trips of great earthquakes in Italy, Mexico and Hong Kong.
Sekiya and Omori published the first clear record of a destructive earthquake, obtained by their measuring devices at the University. In 1886 Sekiya was made chair of seismology and secretary to the Imperial Earthquake Investigation Committee and by the time of his death a decade later, Japan had nearly 1000 seismological recording stations to study seismicity in Japan.
In 1891 Omori was appointed assistant to Sekiya and in 1893 lecturer on seismology at the Imperial University. In 1895, he was sent to Germany and Italy for additional study and visited England briefly on his way home in September, 1896.
Omori became chair of seismology at the University and secretary of the Imperial Earthquake Investigation Committee following Sekya's death on 9 January 1896. He could read English, German, Italian and Japanese and maintained correspondence with many seismologists as well as writing papers in all four languages.