scholarly journals Applicability of silty material brought by black tsunami to estimation of inundation area

2021 ◽  
Vol 9 (5) ◽  
pp. 180-185
Author(s):  
Kousuke Nakamura ◽  
Takeshi Komai
Keyword(s):  
2016 ◽  
Vol 49 (12) ◽  
pp. 981-993 ◽  
Author(s):  
Minkwan Oh ◽  
Dongryul Lee ◽  
Hyunhan Kwon ◽  
Dongkyun Kim

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 896
Author(s):  
Thanh Thu Nguyen ◽  
Makoto Nakatsugawa ◽  
Tomohito J. Yamada ◽  
Tsuyoshi Hoshino

This study aims to evaluate the change in flood inundation in the Chitose River basin (CRB), a tributary of the Ishikari River, considering the extreme rainfall impacts and topographic vulnerability. The changing impacts were assessed using a large-ensemble rainfall dataset with a high resolution of 5 km (d4PDF) as input data for the rainfall–runoff–inundation (RRI) model. Additionally, the prediction of time differences between the peak discharge in the Chitose River and peak water levels at the confluence point intersecting the Ishikari River were improved compared to the previous study. Results indicate that due to climatic changes, extreme river floods are expected to increase by 21–24% in the Ishikari River basin (IRB), while flood inundation is expected to be severe and higher in the CRB, with increases of 24.5, 46.5, and 13.8% for the inundation area, inundation volume, and peak inundation depth, respectively. Flood inundation is likely to occur in the CRB downstream area with a frequency of 90–100%. Additionally, the inundation duration is expected to increase by 5–10 h here. Moreover, the short time difference (0–10 h) is predicted to increase significantly in the CRB. This study provides useful information for policymakers to mitigate flood damage in vulnerable areas.


Author(s):  
Shigeru KATO ◽  
JUNAIDI ◽  
Takumi OKABE ◽  
Shin-ichi AOKI

2016 ◽  
Author(s):  
Kaiheng Hu ◽  
Pu Li ◽  
Yong You ◽  
Fenghuan Su

Abstract. A hydrologically based model is developed for delineating hazard zones in valleys of debris flow basins. The basic assumption of this model is that the ratio of peak discharges of any two cross sections in a debris-flow basin is a power function of the ratio of their flow accumulation areas. Combining the advantages of the empirical and flow routing models of debris-flow hazard zoning, this hydrological model with minimal data requirements has the ability to produce hazard intensity values at different event magnitudes. The algorithms used in this model are designed in the framework of grid- based geographic processing and implemented completely on ArcGIS platform and a Python scripting environment. Qipan basin in the Wenchuan county of Sichuan province, southwest China where a large-scale debris-flow event occurred on July 11, 2013 was chosen as the test case for the model. The hazard zone identified by the model showed good agreement with the real inundation area of the event. The proposed method can help identify small hazard areas in upstream tributaries and the developed model is promising in terms of its application in debris-flow hazard zoning.


Author(s):  
A. J. Adeloye ◽  
F. D. Mwale ◽  
Z. Dulanya

Abstract. In response to the increasing frequency and economic damages of natural disasters globally, disaster risk management has evolved to incorporate risk assessments that are multi-dimensional, integrated and metric-based. This is to support knowledge-based decision making and hence sustainable risk reduction. In Malawi and most of Sub-Saharan Africa (SSA), however, flood risk studies remain focussed on understanding causation, impacts, perceptions and coping and adaptation measures. Using the IPCC Framework, this study has quantified and profiled risk to flooding of rural, subsistent communities in the Lower Shire Valley, Malawi. Flood risk was obtained by integrating hazard and vulnerability. Flood hazard was characterised in terms of flood depth and inundation area obtained through hydraulic modelling in the valley with Lisflood-FP, while the vulnerability was indexed through analysis of exposure, susceptibility and capacity that were linked to social, economic, environmental and physical perspectives. Data on these were collected through structured interviews of the communities. The implementation of the entire analysis within GIS enabled the visualisation of spatial variability in flood risk in the valley. The results show predominantly medium levels in hazardousness, vulnerability and risk. The vulnerability is dominated by a high to very high susceptibility. Economic and physical capacities tend to be predominantly low but social capacity is significantly high, resulting in overall medium levels of capacity-induced vulnerability. Exposure manifests as medium. The vulnerability and risk showed marginal spatial variability. The paper concludes with recommendations on how these outcomes could inform policy interventions in the Valley.


2022 ◽  
Vol 12 (2) ◽  
pp. 858
Author(s):  
Kentaro Imai ◽  
Takashi Hashimoto ◽  
Yuta Mitobe ◽  
Tatsuo Masuta ◽  
Narumi Takahashi ◽  
...  

Tsunami-related fires may occur in the inundation area during a huge tsunami disaster, and woody debris produced by the tsunami can cause the fires to spread. To establish a practical method for evaluating tsunami-related fire predictions, we previously developed a method for evaluating the tsunami debris thickness distribution that uses tsunami computation results and static parameters for tsunami numerical analysis. We then used this evaluation method to successfully reproduce the tsunami debris accumulation trend. We then developed an empirical building fragility function that relates the production of debris not only to inundation depth but also to the topographic gradient and the proportion of robust buildings. Using these empirical evaluation models, along with conventional tsunami numerical analysis data, we carried out a practical tsunami debris prediction for Owase City, Mie Prefecture, a potential disaster area for a Nankai Trough mega-earthquake. This prediction analysis method can reveal hazards which go undetected by a conventional tsunami inundation analysis. These results indicate that it is insufficient to characterize the tsunami hazard by inundation area and inundation depth alone when predicting the hazard of a huge tsunami; moreover, more practically, it is necessary to predict the hazard based on the effect of tsunami debris.


Author(s):  
Taisei SEKIMOTO ◽  
Satoshi WATANABE ◽  
Shunji KOTSUKI ◽  
Masafumi YAMADA ◽  
Shiori ABE ◽  
...  

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