Masahiro Chigira             @@@@@@@@@@@@@@@@@@@@

Professor (Dr of Science, Geologist)
Mountain Hazard Section, GeoDisaster Division
Disaster Prevention Research Institute, Kyoto University
Kyoto University Disaster Prevention Research Institute GeoDisaster Division Mountain Hazard Section

Outline of my research
I have been studying about rock or debris slides, and their precursory phenomena, particularly mass rock creep and rock weathering. I have found that the chemical weathering of clastic rocks in mountainous area is sequential chemical reactions between infiltrating water and rocks, and that characteristic weathering profile is resultantly made. Subsequently, granite and ignimbrite have been also found to have characteristic weathering profiles, which provide basic causes of shallow landslide. Their weathering mechanisms and the resultant weathering profiles reflect their geological origin, which could be used for the identification and assessment of landslide hazard. Beside the chemical weathering, mechanical processes represented by the gravitational rock deformation, which is mass rock creep, proceeds slowly but continually, deteriorating rocks and forming basic causes of catastrophic rock slide. I described various kinds of such deformation. I used to work for the Central Research Institute of Electric Power Industry until 1997, and respect the applicability of science to society. Science for society, research without border, and hazard study during the time without hazard are my motto.

Main research field
Gravitational deformation of mountains and the mechanism of gigantic landslide
(Mainly by field investigation)
Weathering of various rocks and the mechanism of shallow landslide
(Field investigation, laboratory analysis, and experiment)
Recent research themes

Weathering of granite and its relationship with petrological genesis
Geological and geomorphological characteristics of gigantic landslide and their prediction
Prediction and hazard assesment of shallow landslide
Hazard investigation
1997 Hachimantai landslide
1998 Fukushima hazard by rainstorm
1999 Hiroshima hazard by rainstorm
1999 Mass movement hazard by the 1999 Taiwan Chi-Chi earthquake
2000 Kozushima hazard by earthquakes and rainstorms
2002 Hazard in Korea by Typhoon Rusa

2003 Kyushu rainstorm
2003 Chuetsu earthquake

Students supervised
Faculty of the Department of the Earth and Planetary Science of the Graduate School of Science, Kyoto University.

Students and their themes I supervised.

Doctoral course:
Kuniyasu Mokudai (2002) Geomorphological study of gravitational mountain deformation by the toppling type of mass rock creep.

Undergoing
Shoji Doshida: Morphological analysis of landforms by using airborne laser scanner data and GIS.
Hayato Tobe: Mechanisms of weathering and shallow landslide of granitic rocks.
Master course:
Eiki Ito (1999) Rapid reweathering of geologically weathered granite - Case study for the Shigaraki Granite in Shiga Prefecture.
Yoko Suwa (2000) Spheroidal weathering of granite - Case study for the Yagyu Granite in Nara Prefecture.
Osamu Yokoyama (2001) Weathering and landslide of unwelded ignimbrite - Shirasu in the southern Kyushu.
Yuko Miyazaki (2002) Landslide of rhyolitic volcanics triggered by earthquake and rainfall - 2000 hazard in the Kozu Island.
Hironori Kato (2002) Large scale mountain deformation on the Hooh Mountains in Shikoku and its relationship with the fault movement along the Median Tectonic Line.
Hirokazu Furuki (2002) Microcracks made at the early stage of weathering of granite.
Takeshi Hiraki (2002) Slope development in the Hira Mountains along theHanaore fault.
Chizuru Imai (2003): Chemistry of the water infiltrating through weathered granite.
Jun Nemoto (2004): Slope development in melange areas.
Hideaki Hijikata (2004): Reweathering rate of weathered granite.

Undergoing:
Shintaro Yamasaki: Weathering of schist and its landslide
Yusuke Yamamoto: Geological and geomorphological characteristics of cap-rock type landslides
Masahiro Yoshida: Landslides of pyroclastic fall deposits triggered by the1968 Tokachioki earthquake
Chikako Kawahara: Geological causes of landslides induced by the 1971 rainstorm in eastern Chiba.

Invited presentation

Chigira, M. (2004): Shallow landslide mechanism and its susceptibility evaluation from geological view point. France-Japan cooperation on geological hazards. GeoHazards-2004 Workshop, Shizuoka, Kenote Paper.
Chigira, M. (2004): Characteristic weathering profiles made under humid climatic conditions. 3rd@ARMS 2004/Workshop W-2, ISRM International Workshop on Preservation of Natural Stone Monuments and Rock Weathering, Kyoto, Keynote Paper.
Chigira, M. (2003): Weathering and landslide of granite and ignimbrite. European Geophysical Society-American Geophysical Union-European Union of Geoscience Joint Assembly at Nice, France. Invited paper
Chigira, M. (2003): Weathering, landslide, and hazard mapping in granitic area. Keynote paper at the Symposium on Geohazards organized by The Geological Sciety of Korea, Seoul, Keynote Paper.

Academic Societies

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Editorial Board of the Engineering Geology from Elsevier
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