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Dive into the research topics where Hiroshi Suwa is active.

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Featured researches published by Hiroshi Suwa.


Hydrological Sciences Journal-journal Des Sciences Hydrologiques | 1988

Hydrological controls of erosion and sediment transport in volcanic torrents

Kazuo Okunishi; Hiroshi Suwa; Shuji Hamana

Abstract Sediment is transported in the form of debris flows in major gullies dissecting permeable volcanic slopes as exemplified by the Kami-kamihori Valley in the northern Japan Alps. Four years of hydrological observations in the headwater area of the gully showed that the surface runoff which triggers debris flows is related to peak 10- to 20-minute rainfall. Sediment production in such a short time is not sufficient to prepare a debris flow. Therefore, debris must have been accumulated at a particular section by repeated sediment discharge due to minor rainstorms. The volume of the debris produced in the headwaters was evaluated and correlated to an effective rainfall. The quantity of sediment transport at seven sections along the gully by debris flows in three periods was evaluated through the measurement of the topographic changes. It was compared with the total effective rainfall for the pertinent period, and the mean “sediment concentration” in the debris flow was calculated for each section and ...


Natural Hazards | 2001

Assessment of debris-flow hazards of alluvial fans

Kazuo Okunishi; Hiroshi Suwa

A strategy is presented for the assessment ofdebris-flow hazards on alluvial fans on the basis ofa case study carried out on the southern foot of astratovolcano named Mt. Yatsugatake. Transformation ofcommercial forests into a golf course was planned ata corner of the Kikkakezawa fan. The case studyinvolves an assessment of hazards due to debris flowsof different magnitudes and their recurrenceintervals. The environmental conditions for therecurrence of these debris flows are discussed as wellas the extent of the areas affected by them. In orderto generalize the case study, concepts of hazardpotential, hazard and risk for debris flows onalluvial fans are established. Accordingly, the hazardpotential is the possible hazards at any location onan alluvial fan in an indefinitely long time period,which can be assessed on the basis of hydrological andother geoscientific investigations. Hazards associatedwith a particular land use can be evaluated on thebasis of the hazard potential considering the locationand the time period associated with the land use. Riskcan be further assessed considering the life styles inthis land and the social conditions.


Environmental forest science. Proceedings of the IUFRO Division 8 Conference, Kyoto University, Japan, 19-23 October 1998. | 1998

Assessment of Hazard Potential of Debris Flows in Relation to the Reclamation of Forests on the Foot of Volcanoes

Kazuo Okunishi; Hiroshi Suwa

This paper focuses on the hazards due to debris flows in the alluvial fans on the foot of volcanoes. A case study is carried out to assess the hazards associated with the transformation of forests to golf courses. A close examination of geomorphic evidence gives the history of occurrence of the debris flows of varied ages in the past and the estimate of their recurrence. To generalize this result, hazard potential is defined, from which hazard and risk are derived according to the time span, location and details of the reclamation.


Journal of Volcanology and Geothermal Research | 2000

Instrumental lahar monitoring at Merapi Volcano, Central Java, Indonesia

Franck Lavigne; Jean-Claude Thouret; Barry Voight; Kirby D. Young; R. LaHusen; J. Marso; Hiroshi Suwa; A. Sumaryono; D.S. Sayudi; M. Dejean


Geomorphology | 2004

Contrasts between debris flows, hyperconcentrated flows and stream flows at a channel of Mount Semeru, East Java, Indonesia

Franck Lavigne; Hiroshi Suwa


Geomorphology | 2012

Characterization of debris flows by rainstorm condition at a torrent on the Mount Yakedake volcano, Japan

Kazuyuki Okano; Hiroshi Suwa; Tadahiro Kanno


Bulletin of Volcanology | 2007

Volcanic hazards at Mount Semeru, East Java (Indonesia), with emphasis on lahars

Jean-Claude Thouret; Franck Lavigne; Hiroshi Suwa; Bambang Sukatja; Surono


International Journal of Erosion Control Engineering | 2009

Behavior of debris flows monitored on test slopes of Kamikamihorizawa Creek, Mount Yakedake, Japan

Hiroshi Suwa; Kazuyuki Okano; Tadahiro Kanno


Geomorphology | 2004

Special Section preface

Hiroshi Suwa; K Okunishi; P Wassmer


Journal of the Society of Instrument and Control Engineers | 1989

Measurement of Surface Velocity of Debris Flows by Spatial Filtering Velocimetry

Yasumasa Itakura; Hiroshi Suwa; Masahiro Takeuchi

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Masahiro Takeuchi

Kyoto Institute of Technology

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