Numerical Simulation of Drifting and Run-Up Ice Floes Driven by Tsunami

Author(s):  
Shinji Kioka ◽  
Maiko Ishida ◽  
Takahiro Takeuchi

Abstract In order to simulate drifting and run-up ice floes driven by tsunamis, we developed a quasi-3D Discrete Element Method (DEM) in which phenomena unique to granular solids, such as the arch action, jam and pile up of such solids, can be simulated with a small computation load. The validity of the simulation method was verified by hydraulic experiments using synthetic ice. Some numerical simulations of drifting and run-up ice floes driven by a tsunami were performed to investigate the fundamental characteristics of ice run-up and the applicability to actual seas. It was confirmed that the simulation results could estimate risk areas where ice pile up and jam form as well as hazardous areas showing the degree of damage to buildings. Such calculation was expected to be useful for the compilation of hazard maps and the development of disaster mitigation plans in the future.

2020 ◽  
Vol 5 (2) ◽  
pp. 107-121
Author(s):  
Listyo Yudha Irawan ◽  
Nabila Nabila ◽  
Damar Panoto ◽  
Agung Chandra Darmansyah ◽  
Annisa Nur Rasyidah ◽  
...  

Abstrak: Sub DAS Amprong secara administrasi masuk pada wilayah Kabupaten Malang dan Kota Malang. Meliputi lima Kecamatan yakni: Kedungkandang, Poncokusumo, Tumpang, Pakis dan Jabung. Risiko bencana longsor tergolong tinggi pada kawasan ini. Maka dari itu, penelitian ini bertujuan untuk melakukan pengurangan risiko bencana longsor mengunakan pendeketaan GIS (Geographic Information System). Menggunakan GIS distribusi tingkat risiko akan dapat diketahui dengan baik, sehingga mampu memberikan solusi yang lebih akurat. Penelitian ini meliputi empat tahapan: 1) pemetaan bahaya longsor, 2) pemetaan kerentanan bencana, 3) pemetaan kapasitas bencana, 4) pemetaan risiko bencana. Hasilnya diketahui bahwa kecamatan Jabung dan Poncokusumo merupakan wialayah dengan tingkat risiko longsor paling tinggi. Upaya yang dapat dilakukan untuk mengurangi tingkat risiko dapat dilakukan melalui mitigasi bencana secara struktural dan nonstruktural. Wilayah dengan risiko tinggi bukan merupakan kawasan pemukiman, namun memiliki aktivitas utama berupa pertanian. Oleh karena itu perlu adanya manajemen risiko bencana longsor dalam usaha longsor seperti: dengan cara: 1) pengaturan sistem irigasi dengan baik, 2) penerapan sistem terasering, dan 3) pemasangan bronjong pada kaki lereng. Abstract: Amprong watershed is administratively included in Malang Regency and Malang City. Includes five districts namely: Kedungkandang, Poncokusumo, Tumpang, Pakis and Jabung. The risk of landslides is classified high in this region. Therefore, this research aims to reduce the risk of landslides using GIS (Geographic Information System). Using GIS the distribution of risk levels will be well known, so as to provide a more accurate solution. This research includes four stages: 1) mapping of landslide hazards, 2) mapping of disaster vulnerability, 3) mapping of disaster capacity, 4) mapping of disaster risk. The results are known that the Jabung and Poncokusumo sub-districts are areas with the highest risk of landslides. Efforts that can be made to reduce the level of risk can be done through structural and nonstructural disaster mitigation. High risk areas are not residential areas, but have major activities in the form of agriculture. Therefore, it is necessary to have landslide risk management, such as: by: 1) regulating the irrigation system properly, 2) applying the terracing system, and 3) installing gabions at the foot of the slope.


Author(s):  
Dwi Pujiastuti ◽  
Rahmad Aperus ◽  
Rachmad Billyanto

<p class="ISI"><strong>Abstract</strong> Tsunami modeling research has been done on the coast of Bengkulu using software L-2008 and Travel Time Tsunami (TTT). Earthquake historical data that used in this research is the earthquake in Bengkulu on September 12, 2007 which is obtained from BMKG and the USGS. This research is aimed to determine the height (run up) and travel time of the tsunami on the coast of Bengkulu as the tsunami disaster mitigation efforts. Tsunami modelling has been done by validate the run up using tide gauge  data in the area of Padang, Muko-Muko, and Kaur.  In this research used magnitude scenario are 8 M<sub>w</sub>, 8.5 M<sub>w</sub> and 9 M<sub>w</sub>. Local tsunami effect observed were 10 areas along the coast region Bengkulu. Tsunami modeling of Bengkulu in September 12, 2007 results the run up value which is close to the run up value of the measurements. From the modelling result obtained that the quickest area impacted by the tsunami is Enggano Island   which is 27  minutes 46  seconds from earthquake.  The highest tsunami run up value is located in the Bengkulu city. The run up values by using the scenario of magnitude 8M<sub>w</sub> is  2.07 m, 8.5 M<sub>w</sub> is  4.05 m and 9 M<sub>w</sub> is 9.83 m.</p><p class="54IsiAbstractCxSpFirst"> </p><p class="54IsiAbstractCxSpLast"><strong>Keywords:</strong>   tsunami, modelling, software L-2008, software TTT, run up</p><p class="ISICxSpFirst"><strong> </strong></p><p class="ISICxSpLast"><strong>Abstrak</strong> Telah dilakukan penelitian pemodelan tsunami di pesisir Pantai Bengkulu dengan menggunakan <em>software</em><em> </em>L-2008 dan <em>Travel Time Tsunami </em>(TTT). Data historis gempa bumi yang digunakan dalam penelitian ini adalah gempa bumi Bengkulu 12 September 2007 yang diperoleh dari BMKG dan USGS. Penelitian ini bertujuan untuk menentukan tinggi (<em>run up</em>) dan waktu tempuh gelombang tsunami di pesisir Pantai Bengkulu sebagai upaya mitigasi bencana tsunami. Sebagai validasi digunakan data <em>run up </em>stasiun <em>tide gauge yang </em>berlokasi di Padang, Muko-muko dan Kaur. Dalam penelitian ini dilakukan pemodelan tsunami untuk mengestimasi tinggi <em>run up</em><em> </em>dan waktu tempuh penjalaran gelombang tsunami menggunakan skenario magnitudo 8 M<sub>w</sub>, 8,5 M<sub>w</sub> dan 9 M<sub>w</sub>. Sebagai titik tinjau digunakan 10  daerah di sepanjang pantai wilayah Bengkulu. Hasil pemodelan menunjukkan  bahwa nilai <em>run up</em>  tsunami  yang diperoleh mendekati nilai <em>run up</em> hasil pengukuran. Daerah dengan waktu tercepat dihantam gelombang tsunami adalah Pulau Enggano dengan waktu tempuh 27 menit dan 46 detik. <em>Run up</em> tertinggi terjadi di  Kota Bengkulu. dengan  nilai <em>run up</em> yang diperoleh adalah 2,07 m untuk skenario 8 M<sub>w</sub>, 4,05 untuk skenario 8,5 M<sub>w  </sub>dan9,83 m untuk skenario 9 M<sub>w</sub>.</p><p><strong> </strong></p><p><strong>Kata kunci:</strong> :tsunami, pemodelan, <em>software </em>L-2008, <em>software </em>TTT, <em>run up</em></p>


2013 ◽  
Vol 8 (5) ◽  
pp. 861-868 ◽  
Author(s):  
Nobuoto Nojima ◽  
◽  
Satoshi Fujikawa ◽  
Yutaka Ishikawa ◽  
Toshihiko Okumura ◽  
...  

With the aim of better understanding and more effective utilization of probabilistic seismic hazard maps in Japan, exposure analysis has been carried out by combining hazard maps with population distribution maps. Approximately 80% of the population of Japan is exposed to a relatively high seismic hazard, i.e., a 3% probability of exceeding JMAseismic intensity 6 lower within 30 years. In highly populated areas, specifically in major metropolitan areas, seismic hazard tends to relatively high because of the site amplification effects of holocene deposits. In implementing earthquake disaster mitigation measures, it is important to consider the overlapping effect of seismic hazard and demographic distributions.


1994 ◽  
Vol 10 ◽  
pp. 241-245
Author(s):  
Hitoshi Kohama ◽  
Yoshimasa Takahashi ◽  
Akira Imaizumi ◽  
Kunio Enoki ◽  
Hiroshi Saeki
Keyword(s):  
Run Up ◽  

2016 ◽  
Vol 10 (1) ◽  
pp. 848-858
Author(s):  
Jun Wang ◽  
Yan Yu ◽  
Xinfeng Wei ◽  
Qinghua Gong ◽  
Haixian Xiong

Debris flows are a common natural disaster in mountainous areas and often cause severe casualties and property loss. Debris-flow run-out effects analysis can provide an idea of the spatial risks posed to the downstream area of a debris flow, which is extremely important for local populations’ lives, disaster mitigation and planning the layout of economic construction. The objective of this study is to develop a new method to quantify debris flow run-out effects by combining debris flow simulation results and data for different types of land use within the inundated area. After a three-dimensional numerical simulation platform was established, the numerical simulation method was applied as a modeling tool to simulate the inundated areas and final buried depths under rainfalls with different return periods. The simulated result for flow depth under a 100-year return period rainfall event was validated based on field measurements. Finally, the debris-flow run-out effects under different return periods were analyzed by combining the simulation results and land use data. The proposed method can enhance the accuracy of debris-flow spatial risk assessment and has great value for application.


Author(s):  
Congcong Zhang ◽  
Yongliang Wang ◽  
Rixiu Men ◽  
Hong He ◽  
Wei Chen

Floating-ring bearings are widely used in automotive turbocharger machinery because of their robustness, low cost and their suitability under extreme rotation speeds. This type of bearings, however, can become a source of noise due to oil whirl/whip instability. The stabilizing effect of lobed bearing shape is known in the literature, which encourages the researchers to substitute plain cylindrical full floating bearings with lobed geometries in their outer and inner clearances to prevent the rotor-bearing system from developing oil whirl/whip instability or to reduce its amplitude of response when oil whirl/whip instability takes place. In this study, a novel concept of a floating-ring bearing with three-lobed clearances in its inner and outer films is modelled. In order to perform transient simulations, a very time-efficient approximate solution for the Reynolds equation to the geometry of three-lobed bearings is presented. Using the run-up simulation method, the nonlinear dynamic behaviours of a real turbocharger rotor supported by the novel concept of three-lobed floating-ring bearings are systematically investigated. The newly obtained results show that the sub-synchronous vibrations can be thoroughly suppressed with high preload factor at the cost of a moderate increase in the synchronous vibrations. Hence, the three-lobed floating-ring bearings design is an attractive alternative to plain cylindrical floating-ring bearings for automotive turbocharger applications.


Author(s):  
Shinji KIOKA ◽  
Masaya MORI ◽  
Tsutomu ENDO ◽  
Takahiro TAKEUCHI ◽  
Yasunori WATANABE
Keyword(s):  
Sea Ice ◽  

Author(s):  
Shinji KIOKA ◽  
Tsutomu ENDO ◽  
Takahiro TAKEUCHI ◽  
Yasunori WATANABE
Keyword(s):  
Sea Ice ◽  

Author(s):  
Izumi Yoshida ◽  
Akihiko Ozaki ◽  
Tomohiro Morita ◽  
Masaharu Tsubokura ◽  
Masahiro Kami

Abstract Objective: Typhoon Hagibis struck Japan on October 12, 2019. This study documents and characterizes deaths caused by Hagibis and helps identify strategies to reduce mortality in future disasters. Methods: Japanese residents, who were killed by Typhoon Hagibis, as reported by Japan’s Fire and Disaster Management Agency, were considered for the study. Details were collected from mainstream Japanese media, and flooding data from hazard maps published by local municipalities. Results: Out of the 99 total fatalities, 65 (73.0%) were aged 65 years or above. Among those who drowned indoors (20), 18 (90.0%) lived in high-risk areas of flooding, and their bodies were found on the first floor of their residences. A total of 10 (55.6%) out of the 18 fatalities lived in homes with 2 or more floors, indicating that they could have moved upstairs to avoid the floodwater. However, 6 (33.3%) could not do so due to existing health issues. Conclusions: Relatively elderly people, particularly those in areas at high risk of flooding, were most affected. Seeking higher ground is a standard safety measure in times of flooding, but this may not be possible for everyone depending on their health status, structure of their residence, and the depth of floodwaters.


2021 ◽  
Vol 1 (2) ◽  
pp. 40-53
Author(s):  
Novi Asniar ◽  
Anri Noor Annisa Ramadan ◽  
Aso Sudiarjo

Tasikmalaya Regency is an area that is prone to landslides and ground movements. The availability of comprehensive and accurate information in controlling land use for regional development in areas prone to landslides and ground movements is very important for casualty prevention and other losses such as physical, social and economic. This information must be disseminated to the public as an early warning system to support disaster mitigation efforts. Identification of the characteristics of landslide and ground movement prone areas requires the mapping of risk areas to mitigate disasters. This can be done using Geographic Information System (GIS). This mapping activity was carried out using the method of collecting digital data from five vulnerability controlling factors of landslides and ground movements, namely rainfall, rock type, soil type, land cover and slope. The analysis is continued by weighting the factors that influence landslides and ground motion and then overlaying the five controlling factor maps (with their respective weight values) to produce a landslides and ground movement vulnerability level map which is then inputted into WebGIS. This map can then be used by local governments and the public as an information medium to support disaster mitigation activities.


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