scholarly journals Impact of Short-term Temporal Changes in Volcanic Ash Fall on Rainfall Threshold for Debris Flow Occurrence in Sakurajima, Japan

2014 ◽  
Vol 7 (3) ◽  
pp. 75-84
Author(s):  
Hiroshi KISA ◽  
Takao YAMAKOSHI ◽  
Tadanori ISHIZUKA
Keyword(s):  
Debris Flow ◽  
Volcanic Ash ◽  
Rainfall Threshold ◽  
Temporal Changes ◽  
Short Term ◽  
Ash Fall

scholarly journals Temporal changes in the debris flow threshold under the effects of ground freezing and sediment storage on Mt. Fuji

2021 ◽  
Author(s):  
Fumitoshi Imaizumi ◽  
Atsushi Ikeda ◽  
Kazuki Yamamoto ◽  
Okihiro Osaka
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Rainfall Threshold ◽  
Temporal Changes ◽  
Frozen Ground ◽  
Sediment Storage ◽  
Cold Regions ◽  
Initiation Zone ◽  
Ground Freezing ◽  
Channel Deposits

Abstract. Debris flows are one of the most destructive sediment transport processes in mountainous areas because of their large volume, high velocity, and kinematic energy. Debris flow activity varies over time and is affected by changes in hydrogeomorphic processes in the initiation zone. To clarify temporal changes of debris flow activities in cold regions, the rainfall threshold for the debris flow occurrence was evaluated in Osawa failure at a high elevation on Mt. Fuji, Japan. We conducted field monitoring of the ground temperature near a debris flow initiation zone to estimate the presence or absence of seasonally frozen ground during historical rainfall events. The effects of ground freezing and the accumulation of channel deposits on the rainfall threshold for debris flow occurrence were analyzed using rainfall records and annual changes in the volume of channel deposits since 1969. Statistical analyses showed that the intensity-duration threshold during frozen periods was clearly lower than that during unfrozen periods. A comparison of maximum hourly rainfall intensity and total rainfall also showed that debris flows during frozen periods were triggered by a smaller magnitude of rainfall than during unfrozen periods. Decreases in the infiltration rate due to the formation of frozen ground likely facilitated the generation of overland flow, triggering debris flows. During unfrozen periods, the rainfall threshold was higher when the volume of channel deposits was larger. Increases in the water content in channel deposits caused by the infiltration of rainfall is likely important for the debris flow occurrence during unfrozen periods. The results suggest that the occurrence of frozen ground and the sediment storage volume need to be monitored and estimated for better debris flow disaster mitigation in cold regions.

scholarly journals Temporal changes in the debris flow threshold under the effects of ground freezing and sediment storage on Mt. Fuji

2021 ◽  
Vol 9 (6) ◽  
pp. 1381-1398
Author(s):  
Fumitoshi Imaizumi ◽  
Atsushi Ikeda ◽  
Kazuki Yamamoto ◽  
Okihiro Ohsaka
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Rainfall Threshold ◽  
Temporal Changes ◽  
Frozen Ground ◽  
Sediment Storage ◽  
Cold Regions ◽  
Initiation Zone ◽  
Ground Freezing ◽  
Channel Deposits

Abstract. Debris flows are one of the most destructive sediment transport processes in mountainous areas because of their large volume, high velocity, and kinematic energy. Debris flow activity varies over time and is affected by changes in hydrogeomorphic processes in the initiation zone. To clarify temporal changes in debris flow activities in cold regions, the rainfall threshold for the debris flow occurrence was evaluated in Osawa failure at a high elevation on Mt. Fuji, Japan. We conducted field monitoring of the ground temperature near a debris flow initiation zone to estimate the presence or absence of seasonally frozen ground during historical rainfall events. The effects of ground freezing and the accumulation of channel deposits on the rainfall threshold for debris flow occurrence were analyzed using rainfall records and annual changes in the volume of channel deposits since 1969. Statistical analyses showed that the intensity–duration threshold during frozen periods was clearly lower than that during unfrozen periods. A comparison of maximum hourly rainfall intensity and total rainfall also showed that debris flows during frozen periods were triggered by a smaller magnitude of rainfall than during unfrozen periods. Decreases in the infiltration rate due to the formation of frozen ground likely facilitated the generation of overland flow, triggering debris flows. The results suggest that the occurrence of frozen ground and the sediment storage volume need to be monitored and estimated for better debris flow disaster mitigation in cold regions.

Temporal Changes in Pollen Grain Concentration Predict Short-Term Clinical Outcomes in Acute Coronary Syndromes

2021 ◽  
Vol 30 ◽  
pp. S112
Author(s):  
O. Al-mukhtar ◽  
S. Vogrin ◽  
S. Noaman ◽  
E. Lampugnani ◽  
D. Dinh ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Acute Coronary Syndromes ◽  
Temporal Changes ◽  
Pollen Grain ◽  
Short Term ◽  
Coronary Syndromes

Variability in rainfall threshold for debris flow after the Chi-Chi earthquake in central Taiwan, China

2009 ◽  
Vol 24 (2) ◽  
pp. 177-188 ◽  
Author(s):  
C.L. SHIEH ◽  
Y.S. CHEN ◽  
Y.J. TSAI ◽  
J.H. WU
Keyword(s):  
Debris Flow ◽  
Rainfall Threshold ◽  
Central Taiwan

Analyzing the impact of grazing and short-term irrigation management on soil mechanical strength of a volcanic ash soil under different types of pastures

2021 ◽  
Vol 213 ◽  
pp. 105130
Author(s):  
Dorota Dec ◽  
Sebastián Bravo ◽  
Rainer Horn ◽  
Daniel Uteau ◽  
Stephan Peth ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Volcanic Ash ◽  
Irrigation Management ◽  
Short Term ◽  
Volcanic Ash Soil ◽  
Different Types ◽  
The Impact

scholarly journals Estimating building vulnerability to volcanic ash fall for insurance and other purposes

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
R. J. Blong ◽  
P. Grasso ◽  
S. F. Jenkins ◽  
C. R. Magill ◽  
T. M. Wilson ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Building Vulnerability ◽  
Ash Fall

scholarly journals A preliminary volcanic ash fall susceptibility map of Canada

2015 ◽  
Author(s):  
M C Kelman
Keyword(s):  
Volcanic Ash ◽  
Susceptibility Map ◽  
Ash Fall

scholarly journals Priming effect of the addition of maize to a Japanese volcanic ash soil and its temperature sensitivity: a short-term incubation study

2019 ◽  
Vol 65 (5) ◽  
pp. 444-450 ◽  
Author(s):  
Yasuo Iimura ◽  
Issei Tabara ◽  
Kosuke Izumitsu ◽  
Nobuhide Fujitake
Keyword(s):  
Temperature Sensitivity ◽  
Priming Effect ◽  
Volcanic Ash ◽  
Short Term ◽  
Incubation Study ◽  
Volcanic Ash Soil

Volcanic ash fall impacts

2015 ◽  
pp. 281-288 ◽  
Author(s):  
T.M. Wilson ◽  
S.F. Jenkins ◽  
C. Stewart
Keyword(s):  
Volcanic Ash ◽  
Ash Fall
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