25 Facts About Fusakichi Omori

Fusakichi Omori was a pioneer Japanese seismologist, second chairman of seismology at Tokyo Imperial University and president of the Japanese Imperial Earthquake Investigation Committee.

Fusakichi 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 Tokyo Imperial University.

Sekiya and Fusakichi Omori published the first clear record of a destructive earthquake, obtained by their measuring devices at the university.

In 1891 Fusakichi Omori was appointed assistant to Sekiya and in 1893 lecturer on seismology at the Imperial University.

Fusakichi Omori became chair of seismology at the university and secretary of the Imperial Earthquake Investigation Committee following Sekya's death on 9 January 1896.

Fusakichi Omori could read English, German, Italian and Japanese and maintained correspondence with many seismologists as well as writing papers in all four languages.

Fusakichi Omori found the strike-slip fault cut the surface for at least 40 miles and that the north-east side had shifted relative to the other side a distance of one to two meters.

Fusakichi Omori conducted measurements of the three principal phases of earthquake motion originally described by Milne: the preliminary tremors, the main portion and the end portion, and visited areas after major earthquakes to ground verify the data collected by his instruments.

Fusakichi Omori arrived in Japanese Formosa shortly after the 17 March 1906 Meishan earthquake, later describing soil liquefaction and the complete destruction of Meishan town.

Fusakichi Omori ascribed the high number of casualties due to structure collapse of the dominant local building type: sun-dried brick walls loosely cemented with mud and overlaid by heavy roof beams.

Previously, in 1889 Fusakichi Omori had worked with John Milne to record experiments carried out at the Engineering college at the University of Tokyo to investigate the overturning and fracturing of brick and other columns by horizontally applied motion.

Fusakichi Omori later continued this research and is recognized in earthquake engineering as the first to research the effects of earthquakes on man-made structures through implementing the usage of shaking tables and comparing experimental results with measurements during actual earthquakes.

At the 1908 Messina earthquake, Fusakichi Omori noted the large loss of life, perhaps 75,000 and said that of those 99 percent had died because their houses were not built to withstand earthquakes.

Worldwide, the two most common types of seismographs at the time, the Milne-type and Bosch-Fusakichi Omori seismographs recorded the San Francisco earthquake.

Fusakichi Omori continued his observations south into the Eel River Valley, stopped in Ferndale, California and noted a giant landslide south of Centerville at False Cape which covered the former coast road and created a new promontory into the Pacific Ocean as well as damage to local property and buildings.

In person, and in his writings, Fusakichi Omori followed the visible land trace of the fault 150 miles south to San Jose from Point Arena, but pointed out that the line continued 120 miles northward, underwater to the False Cape landslide south of Eureka, California.

Fusakichi Omori studied the directions of the movement by studying tombstones south of San Francisco, and cracks in the walls of buildings including the St James Hotel in San Jose.

Fusakichi Omori described the faulting in California as parallel to the strike of the fault caused by shear stresses on the plane of fracture.

Fusakichi Omori seismographs were rapidly installed all over northern California, and a list of aftershocks to the San Francisco earthquake was compiled and published.

Fusakichi Omori returned to Japan 4 August 1906 aboard the Doric.

From one of his earliest papers describing the eruption of Mount Azuma in 1893 to his death, Fusakichi Omori studied Japanese volcanos.

Fusakichi Omori described several types of volcanic earthquakes from data obtained at regular eruptions of Mount Asama in central Japan, the 1910 Mount Usu eruption and the 12 January 1914 eruption of Sakurajima.

In 1912 Fusakichi Omori shipped to Hawaii two instruments, an Fusakichi Omori-type Horizontal Tromometer and a seismograph, to be placed on the specially built foundations.

In fall 1923 Fusakichi Omori attended the Second Pan-Pacific Science Congress in Australia, where he and Edward Pigot, the director of the observatory at Riverview College in Sydney, Australia observed a seismograph recording the major great Kanto earthquake which destroyed Yokohama and Tokyo on 1 September 1923, killing about 140,000 and leaving 1.9 million people homeless.

Fusakichi Omori returned to Japan from Melbourne, Australia on board the Tenyo Maru on 4 October 1923.