Name: Takeo, Minoru
Division/Center: Volcano Research Center
Research Area: Seismology, Volcano Physics

Last Update 05/21 2014


Our main research interest is understanding of physical processes of tectonic and volcanic earthquakes, and of volcanic eruption, mainly based on analyses of seismographs.ĦĦIn order to understand the physical process of earthquakes systematically, we need to examine the complexity of rupture processes and its general characteristics. Intending this research, we extend the dislocation model of earthquake to cover phenomena including more general deformations, and derive a general expression for the rotational motion of seismic waves. This study makes it clear that we can estimate the spatial variation of slip velocity even in the source area of small earthquakes. To understand the nature of volcanic eruptions, we studied the volcanic earthquakes and tremors associated with volcanic activity. We often observed volcanic earthquakes and tremors whose waveforms had non-linear characteristics, being considered to have relations with volcanic fluids. We are also developing a new approach to reveal non-linear dynamics of volcanic earthquakes and tremors based on observational seismic and geodetic data.


Takeo, M., Source mechanisms of Usu volcano, Japan, earthquakes and their tectonic implications, Phys. Earth Planet. Inter., 32, 241--264, 1983.

Takeo, M., Rupture process of the 1980 Izu-Hanto-Toho-Oki earthquake deduced from strong motion seismograms, Bull. Seism. Soc. Am., 78, 3, 1074--1091, 1988.

Takeo, M., H. Yamasato, I. Furuya, and M. Seino, Analysis of long-period seismic waves excited by the November 1987 eruption of Izu-Oshima volcano, J. Geophys. Res., 95, B12, 19377--19393, 1990.

Takeo, M., The Rupture Process of the 1989 Offshore Ito Earthquakes Preceding a Submarine Volcanic Eruption, J. Geophys. Res., 97, B5, 6613--6627, 1992.

Uhira, K., and M. Takeo, The source of explosive eruptions of Sakurajima volcano, Japan, J. Geophys. Res., 99, B9, 17775--17789, 1994.

Takeo, M., and H. M. Ito, What can be learned from rotational motions excited by earthquakes?, Geophys. J. Int., 129, 319--329, 1997.

Ide, S., and M. Takeo, Determination of constitutive relations of fault slip based on seismic wave analysis, J. Geophys. Res., 102, B12, 27379--27391, 1997.

Takeo, M., and H. Kanamori, Simulation of Long-Period Ground Motion near a Large Earthquake, Bull. Seism. Soc. Am., 87, 1, 140--156, 1997.

Minoru Takeo, Ground rotational motions recorded in near-source region of earthquakes, Geophys. Res. Lett., 25, 6, 789--792, 1998.

Takeo, M., H. Ueda, Y. Okabe, and M. Matsuura, Waveform characteristics of deep low-frequency earthquakes: time-series evolution based on the theory of the KM2O-Langevin equation, Geophys. J. Int., 165, 87--107, 2006.

Minoru Takeo, Yosuke Aoki, Takao Ohminato, Maki Yamamoto, Magma supply path beneath Mt. Asama volcano, Japan, Geophys. Res. Lett., 33, L15310 doi, , 2006.

Takeo, M., Rotational motions observed during an earthquake swarm in April, 1998, at Offshore Ito, Japan, Bull. Seism. Soc. Am., 99, 2B, 1457--1467, 2009.

Nakamula, S., and M. Takeo, Frequency structure of deep low-frequency tremors occurring in western Shikoku region, Japan, Geophys. J. Int., 180, , 2010.

Nagaoka, Y., K. Nishida, Y. Aoki, M. Takeo, and T. Ohminato, Seismic imaging of magma chamber beneath an active volcano, Earth Planet. Sci. Lett., 333-334, 1-8, doi: 10.1016/j.epsl.2012.034, 2012, , 2012.

Aoki, Y., M. Takeo, T. Ohminato, Y. Nagaoka, and K. Nishida, Structural controls on magma pathways beneath Asama Volcano, Japan, Geological Society London Special Publications, 380, , 2012.

Takeo, M., Y. Maehara, M. Ichihara, T. Ohminato, R. Kamata, and J. Oikawa, Ground Deformation Cycles in a Magma-effusive Stage, and Sub-Plinian and Vulcanian Eruptions at Kirishima Volcanoes, Japan, J. Geophys. Res., 118, doi:10.1002/jgrb.50278, , 2013.

Teisseyre, R., M. Takeo, and E. Majewski (Eds.), Earthquake Source Asymmetry, Structural Media and Rotation Effects, Springer, 2006.