scholarly journals Centennial to Multi-Decadal Morphology Change and Sediment Budget Alteration with Consideration of the Impacts of the 2011 Tohoku Earthquake Tsunami along the Nobiru Coast, Japan

2021 ◽  
Vol 9 (3) ◽  
pp. 265
Author(s):  
Nguyen Trong Hiep ◽  
Hitoshi Tanaka ◽  
Nguyen Xuan Tinh
Keyword(s):  
Morphological Changes ◽  
River Mouth ◽  
Tohoku Earthquake ◽  
Sediment Budget ◽  
Sediment Supply ◽  
The 2011 Tohoku Earthquake ◽  
Morphology Change ◽  
Longshore Transport ◽  
Sediment Input ◽  
The Government

The Nobiru Coast is situated on the southwest of the Ishinomaki Bay. The 2011 Great East Japan Tsunami severely devastated the Nobiru Coast and the adjacent Naruse River mouth. In this study, an investigation was conducted based on the available historic maps and images combined with in situ surveys that revealed the century-to-decade morphology change and sediment budget alteration in the Nobiru Coast. During the past two centuries, the longshore transport on the northeast coast and sediment supply from the Naruse River were the principal sediment supply onto the Nobiru Coast and the estimated annual net sediment input into the coast was 87,000 m3/y. Until several decades ago, the construction of the Ishinomaki Port and the erosion preventing constructions (breakwaters, headlands) along the Ohmagari Coast on the northeast areas caused a dramatic reduction of longshore transport to the Nobiru Coast. Hence, the net sediment input fell to 46,000 m3/y. After the tsunami, the sediment input was further reduced to 29,000 m3/y and this loss was closely related to the intruded sediment into the Naruse River. The outcomes of this study are highly valuable for the government authorities to manage the long-term coastal and riverine morphological changes after the 2011 tsunami.

scholarly journals Morphological Changes of the Lower Ping and Chao Phraya Rivers, North and Central Thailand: Flood and Coastal Equilibrium Analyses

2019 ◽  
Vol 11 (1) ◽  
pp. 152-171 ◽  
Author(s):  
Nikhom Chaiwongsaen ◽  
Parisa Nimnate ◽  
Montri Choowong
Keyword(s):  
Morphological Changes ◽  
River Mouth ◽  
Sediment Supply ◽  
Gulf Of Thailand ◽  
River Bank ◽  
Water Storage Capacity ◽  
Rainfall Condition ◽  
Sand Bar ◽  
Geomorphological Changes ◽  
Chao Phraya River

Abstract The Chao Phraya River flows in the largest river basin of Thailand and represents one of the important agricultural and industrial areas in Southeast Asia. The Ping River is one major upstream branch flowing down slope southwardly, joining the Chao Phraya River in the low-lying central plain and ending its course at the Gulf of Thailand. Surprisingly, the overflow occurs frequently and rapidly at the Lower Ping River where channel slope is high, and in particular area, sand-choked is extensively observed, even in normal rainfall condition. In contrary, at the downstream part, the erosion of river bank and shoreline around the mouth of Chao Phraya River has been spatially increasing in place where there should be a massive sediment supply to form a delta. Here we use Landsat imageries taken in 1987, 1997, 2007 and 2017 to analyze geomorphological changes of rivers. Results show that both rivers have undergone the rapid decreasing of water storage capacity and increasing of sand bar areas in river embayment. The total emerged sand bar area in the Lower Ping River increases from 1987 to 2017 up to 28.8 km2. The excessive trapped bed sediments deposition along the upper reaches is responsible for the shallower of river embankment leading to rapid overflow during flooding. At the Chao Phraya River mouth, a total of 18.8 km2 of the coastal area has been eroded from 1987 to 2017.This is caused by the reducing of sediment supply leading to non-equilibrium in the deltaic zone of the upper Gulf of Thailand. There are several possibility implications from this study involving construction of weir, in-channel sand mining, reservoir sedimentation and coastal erosion management.

Deformation of Sandy Beach and Inundation on Iwama-Sanuka Coast in Fukushima Prefecture due to the 2011 Tohoku Earthquake Tsunami

2012 ◽  
Vol 7 (sp) ◽  
pp. 476-484 ◽  
Author(s):  
Takaaki Uda ◽  
◽  
Kazuya Sakai ◽  
Yukiyoshi Hoshigami ◽  
Yasuhito Noshi ◽  
...  
Keyword(s):  
Sandy Beach ◽  
River Mouth ◽  
Tohoku Earthquake ◽  
Field Observations ◽  
The 2011 Tohoku Earthquake ◽  
Tsunami Inundation ◽  
Fukushima Prefecture ◽  
Inundation Depth ◽  
Miyagi Prefecture ◽  
Mouth Bar

The massive earthquake with a magnitude of 9.0 occurred at 14:46 on March 11, 2011, with an epicenter 130 km offshore from the Oshika Peninsula in Japan’s northeastern Miyagi Prefecture. After the earthquake, large tsunamis were generated owing to abrupt crustal subsidence and uplift, which inundated Japan’s eastern Pacific Ocean coastline. We carried out field observations to investigate the deformation of a previous river-mouth bar by comparing oblique photographs, and investigated the damage to seawalls and the tsunami inundation depth on the Iwama-Sanuka coast, located north of the Same River in southern Fukushima Prefecture. Here, the results of the field observations on the deformation of the sandy beach and the inundation of the Iwama-Sanuka coast are reported.

Macro Analysis of Initial Responses from Yabuki Municipal Government After the 2011 Tohoku Earthquake

2014 ◽  
Vol 9 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Muneyoshi Numada ◽  
◽  
Kimiro Meguro
Keyword(s):  
Municipal Government ◽  
Food Service ◽  
Tohoku Earthquake ◽  
Initial Response ◽  
2011 Tohoku Earthquake ◽  
Difficulty Level ◽  
The 2011 Tohoku Earthquake ◽  
Staff Members ◽  
Service Water ◽  
The Government

An effective initial response immediately after disaster strikes is not easy to provide when human and material resources and information are lacking. The purpose of this study is to achieve effective initial response activities immediately after disaster strikes, and it analyzes the initial responses taken by the government of the town of Yabuki, Fukushima Prefecture in the case of the 2011 Tohoku Earthquake. Disaster responses taken in the first five days after the disaster struck Yabuki are discussed in this paper. As a result, we have found that many staff members were deployed to nonregular works, such as food service, water service, and the sorting and transporting of materials, that could have been done even without town government staff members. To effectively deploy about all Yabuki staff members and conduct disaster response activities, it is necessary to classify the difficulty level of tasks, identify what each task entails, and then allocate the necessary resources to those tasks.

scholarly journals Impact of River Dams on Littoral Cells Located Adjacent to the River Mouth

2021 ◽  
Vol 16 (3) ◽  
pp. 942-952
Author(s):  
KAMAL NAG
Keyword(s):  
Image Processing ◽  
Suspended Sediment ◽  
River Mouth ◽  
Temporal Analysis ◽  
Sediment Budget ◽  
Sediment Supply ◽  
Water Diversion ◽  
Littoral Cells ◽  
Geomorphological Changes ◽  
The Impact

Terrestrial sediment is a major source of sediment to all coasts. Suspended sediment is carried away by the rivers and supplied to the coast to maintain sediment budget. The construction of dams across the rivers arrest sediment behind it and affect the sediment budget of littoral cells along the coast. Reduction in sediment supply induces ecological as well as geomorphological changes along the shoreline. Coastal erosion may accelerate due to reduced sediment influx. With the growing number of cross-river dams and water diversion projects, it has become a major concern before the scientific community to measure, understand and find solutions to multi-fold geo-environmental problems that are arising out of river damming. The present study aims to find out the impact of dams on the coast. It examines how the changes in the suspended sediment supply of an Indian river impact the coast in terms of loss of area due to erosion. Temporal analysis of geomorphological changes along the shoreline in relation to sediment influx holds immense importance to coastal management essential for the sustainable life and livelihood of coastal communities. Scientific investigation into the impact of river dams on the coastal environment is likely to provide a strong ground to reconsider the way present basin development projects function. Areal changes in littoral sediment cells adjacent to the river mouth have been quantified and correlated with changes in sediment influx. Changes along the shorelines have been detected through multispectral satellite images of Landsat belonging to different dates. Image processing and quantification of changes have been performed in QGIS 3.14 “Pi” platform. Virtual raster, raster calculator, field calculator and other required tools in QGIS were used during image processing.

Coastal development in southwestern Bangladesh: understanding the interplay between storms and sea level rise

2021 ◽  
pp. 030913332110461
Author(s):  
Md. Masidul Haque ◽  
Manoj Kumer Ghosh ◽  
Koichi Hoyanagi
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Satellite Images ◽  
Morphological Changes ◽  
Coastal Region ◽  
River Mouth ◽  
Sedimentary Facies ◽  
Sediment Supply ◽  
Coastal Development ◽  
Silty Sand

Sea-level rise and sediment supply have influenced coastal morphology and sedimentation on Bangladesh’s southwestern Ganges‐Brahmaputra‐Meghna (GBM) delta coast. Satellite images and geological core from the Haringhata coastal region were analyzed to explain the morphological changes and to understand the influences on deposits. The results derived from satellite images indicate that the southern coastline experienced a retreat that ranges between 2.3 and 2.9 km. In contrast, the eastern and western coastline advanced. The erosion and accretion ratio was 0.29 from 1977 to 1989, while the ratio was higher 2.90–4.77 from 1989 to 2020. Two sedimentary facies were identified using 130 cm thick successions. A parallel to wavy laminated bluish gray mud facies of deeper part was deposited in a marine-influenced environment. A planar to hummocky cross stratified, gray to grayish white silty sand facies of storm overwash deposits overlies the mud facies with sharp contacts. Unimodal to bimodal grain distributions of sandy sediments suggest two sources: sand derived from the beach and mud carried by adjacent tidal rivers and resuspended offshore sediment. Coastline dynamics and sedimentation of the area were influenced by inequality of accommodation and sediment supply ratio in the river mouth. This occurs due to sea-level rise and deficit in upstream water and sediment discharge. Morphological change along the southwestern GBM delta coast was not only caused by wave energy, but also by rising sea levels which shifted sediment accommodation space landward.

scholarly journals Middle-Scale Ionospheric Disturbances Observed by the Oblique-Incidence Ionosonde Detection Network in North China after the 2011 Tohoku Tsunamigenic Earthquake

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 1000
Author(s):  
Jin Wang ◽  
Gang Chen ◽  
Tao Yu ◽  
Zhongxin Deng ◽  
Xiangxiang Yan ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Oblique Incidence ◽  
North China ◽  
Tohoku Earthquake ◽  
Ionospheric Disturbances ◽  
Doppler Measurement ◽  
The 2011 Tohoku Earthquake ◽  
Tsunamigenic Earthquake ◽  
The Pacific ◽  
The Pacific Ocean

The 2011 Tohoku earthquake and the following enormous tsunami caused great disturbances in the ionosphere that were observed in various regions along the Pacific Ocean. In this study, the oblique-incidence ionosonde detection network located in North China was applied to investigate the inland ionospheric disturbances related to the 2011 tsunamigenic earthquake. The ionosonde network consists of five transmitters and 20 receivers and can monitor regional ionosphere disturbances continuously and effectively. Based on the recorded electron density variations along the horizontal plane, the planar middle-scale ionospheric disturbances (MSTIDs) associated with the 2011 Tohoku tsunamigenic earthquake were detected more than 2000 km west of the epicenter about six hours later. The MSTIDs captured by the Digisonde, high-frequency (HF) Doppler measurement, and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellite provided more information about the far-field inland propagation characteristics of the westward propagating gravity waves. The results imply that the ionosonde network has the potential for remote sensing of ionospheric disturbances induced by tsunamigenic earthquakes and provide a perspective for investigating the propagation process of associated gravity waves.

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