Matuyama (Matsuyama), Motonori
MATUYAMA (MATSUYAMA), MOTONORI
(b. Uyeda [now Usa], Japan, 25 October 1884; d. Yamaguchi, Japan, 27 January 1958)
physics, geophysics, geology.
Matuyama was the son of a Zen abbot, Tengai Sumiye. In 1910 he was adopted by the Matusyama family, whose daughter, Matsuye Matsuyama, he married. He altered the romanized spelling of his adoptive name in about 1926, in conformity with a then new convention of transliteration. Matuyama received his early education in the schools of Kiyosuye and Chõfu, then entered Hiroshima Normal College (now the University of Hiroshima), where he studied physics and mathematics, graduating in 1907. After a year of teaching at a junior high school in Tomioka, Matuyama entered the Imperial University in Kyoto to further his study of physics; he graduated in 1911, then took up postgraduate study of geophysics with Toshi Shida and astronomy with Shizō Shinjō. With Shida he began work on what became on of his chief fields of research, the determination of gravity by pendulum. Matuyama’s first papers were written in collaboration with his teacher and constitute the third and sixth parts of Shida’s “On the Elasticity of the Earth and the Earth’s Crust” of 1912.
Matuyama was appointed lecturer at the Imperial University in 1913; three years later he was promoted to assistant professor of the Geophysical Institute. His doctoral dissertation, which he published in 1918, was entitled “Determination of the Second Derivatives of the Gravitational Potential on Jaluit Atoll,” and contained the results of experiments performed with the Eötvös gravity-variometer to determine the depth of the atoll. Matuyama had spent a month on Jaluit with a collaborator, H. Kaneko, in February 1915; his paper was the first to suggest that the determination of microfeatures of the gravity field of the earth could reveal geological substructure. It became the basis for the development in Japan of the torsion-balance method of prospecting for underground minerals.
In 1919 Matuyama left Japan for the United States to study geophysics with T. C. Chamberlin at the University of Chicago. While there he conducted laboratory experiments on ice designed to illuminate the mechanics of glacial movement. His results were published in 1920 as “On Some Physical Properties of Ice.” Chamberlin wrote an introductory note to the paper, in which Matuyama stated the conclusion:
These facts seem to show that gliding planes parallel to the base of each crystal are not the controlling factor in the deformation of ice and probably are not even an important factor. But instead, adjustment along the contact surfaces of adjacent crystals and perhaps the development of planes of weakness in the constituent crystals parallel to their long axis seem more effective in the process of deformation.
Matuyama returned to Japan in December 1921; the following January he was appointed professor of theoretical geology at the Imperial University. He once again took up the determination of gravity by pendulum. As early as 1911, while he was still a postgraduate student, Matuyama had participated in the national gravity survey of the Imperial Japanese Geodetic Commission; from 1927 until 1932 he extended the survey to Korea and Manchuria. In October 1934 and October 1935 he made a survey of marine gravity, using the Vening-Meinesz pendulum apparatus mounted in a navy submarine, in the Japan Trench and the area surrounding it. During the same period he also determined the gravity of nine islands in the Caroline and Mariana groups and as part of his maritime survey of 1935 landed his equipment on Chichijima in the Bonin Islands to determine its gravity. He found the free-air anomalies in these ten islands to range between +214 and +357 milligal, a result consistent in magnitude with those established for other oceanic islands.
One aspect of Matuyama’s research on gravity was dictated by the request put to the Japanese delegation by the International Union of Geodesy and Geophysics, probably at the meeting of 1936, to carry out a gravity survey in the water areas surrounding the Japan Trench. The sea bottom of the landward side of the deepest line of the trench is the site of strong earthquakes that produce tsunami waves on the Pacific coast of northeast Honshu. In examining the distribution of free-air anomalies over the trench, Matuyama discovered that in the region of the northeast Pacific coasts of Honshu and the Pacific coast of Hokkaido the axis of the negative minimum of anomalies does not occur just above the axis of the maximum depths of the trench, contrary to expectations, but rather shifts landward, while the two axes are almost coincident in the southern part of the trench along the east side of the Fuji volcanic range. (Matuyama’s associate Naoiti Kumagai took up these results a few years later and discovered a clear correlation between the earthquakes that occur in this area and the isostatic anomalies of great magnitude that are also apparent there.)
Matuyama was further concerned with the study of distribution of various kinds of coral reefs in the South Seas. The peculiarity of this distribution had first interested him on his visit to Jaluit atoll in 1915; he noted that in the Mariana group such reefs are elevated above sea level, while in the Marshalls they exist as atolls, or have subsided completely. He theorized that the ocean floor in this area had tilted eastward, and recommended to the Japanese Association for the Advancement of Science that a research commission be appointed to study the tilt of the sea bed in this area. A committee was appointed in 1934, and research stations were established on Saipan and on Jaluit atoll; no reports of their observations were published, however.
The last of Matuyama’s main areas of research was the remnant magnetization of rocks. The first specimen that he examined was a basalt block from Genbudō, Tazima, in western Japan; he then extended his investigation to thirty-six specimens of basalt, each taken from a different site in Japan, Korea, and Manchuria. He subjected each specimen to tests for remnant magnetization, using Gauss’s analysis of the vertical component of the magnetic field of the earth originating within the earth. Matuyama published his results in a series of papers. The most important, published in 1929 and entitled “On the Direction of Magnetization of Basalt in Japan, Tyōsen [Korea] and Manchuria,” offers his conclusion that “According to Mercanton the earth’s magnetic field was probably in a greatly different or nearly opposite state in the Permo-Carboniferous and Tertiary Periods, as compared to the present. From my results it seems as if the earth’s magnetic field in the present area has changed even reversing itself in comparatively short times in the Miocene and also Quaternary Epochs.” This work was widely influential, and the term “Matuyama Epoch” was coined to indicate the paleomagnetic period—from about the late Pliocene to the middle Pleistocene—during which the direction of magnetic field of the earth is supposed to have been opposite to what it is at present.
Matuyama also wrote a series of early papers on seismology, a subject which he originally pursued with Shida, and a great number of miscellaneous papers and books addressed to laymen and students. He served the Imperial University as dean of the Faculty of Science from June 1936 until December 1937; he retired from teaching in 1944 and was made professor emeritus in 1946. In May 1949 Matuyama was appointed president of the University of Yamaguchi; the following year he was elected a fellow of the Japan Academy. He had a lifelong interest in the Noh drama, and organized Noh groups among his neighbors and colleagues in both Kyoto and Yamaguchi. He died following the onset of acute myelogenous leukemia.
Matuyama’s important papers include “Note on Hecker’s Observation of Horizontal Pendulums” and “Change of Plumb Line Referred to the Axis of the Earth as Found From the Result of the International Latitude Observations,” pts. 3 and 6, respectively, of Toshi Shida, “On the Elasticity of the Earth and the Earth’s Crust,” in Memoirs of the College of Science and Engineering, KyotoImperial University, 4, no. 1 (1912), both written with Shida; “Determination of the Second Derivatives of the Gravitational Potential on the Jaluit Atoll,” in Mimoirs of the College of Science,Kyoto Imperial University, 3 (1918), 17–68; “On Some Physical Properties of Ice,” in Journal of Geology, 28 (1920), 607–631; “On the Gravitational Field at the Fushun Colliery, Manchuria,” in Japanese Journal of Astronomy and Geophysics, 2 (1924),91–102; “Probable Subterranean Intrusion of Magma to the North of Sakurajima Volcano,” in Proceedings of the Third Pan-Pacific Science Congress (Tokyo, 1926), 782–783; “Torsion Balance Observation and its Value in Prospecting” [in Japanese], in Tōyō-Gakugei-Zasshi,520 (1926), 476–494; “On the Subterranean Structure Around Sakurajima Volcano Considered From the State of Gravitational Fields,” in Japanese Journal of Astronomy and Geophysics, 4 (1927), 121–138; “Gravity Measurements in Tyōsen and Manchuria,” in Proceedings of the Fourth Pacific Science Congress (Djakarta, 1929), 745–747; “Study of the Underground Structure of Suwa Basin by Means of the Eötvös Gravity-Variometer,” ibid., 869–872; “On the Direction of magnetization of Basalt in Japan, Tyōsen and Manchjuria,” ibid., 567–569, and in Proceedings of th Imperial Academy of japan, 5 (1929), 203–205; “Subterranean Structure of Takamati oil Field Revealed by Gravitational Method,” in Japanese journal of Astronomy and Geophysics, 7 (1930), 47–81, written with H. Higasinaka; “Relative Measurements of Gravity in Japan, Tyāsen and Manchuria Since 1921,” in Travaus. Association internationale de géodésie, Japan Report no. 2, 11 (1933), 1–6; “Measurements of Gravity Over Nippon Trench on Board H. I. M. Submarine Ro-57. Preliminary Report,” in Proceedings of the Imperial Academy of Japan, 10 (1934), 625–628: “Distribution of Gravity Over the Nippon Trench and Related Areas,” ibid., 12 (1936), 93–95; and “Gravity Survey by the Japanese Geodetic Commission Since 1932,” in Travaux. Association internationale de géodésie, Japan Report no. 2, 12 (1936), 1–8.