Hiroshima Prefecture geo-disasters due to Western Japan Torrential rainfall in July 2018

Hashimoto, Ryota; Tsuchida, Takashi; Moriwaki, Takeo; Kano, Seiji

doi:10.1016/j.sandf.2019.11.010

Cited by 23 publications

(9 citation statements)

References 4 publications

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“…We used two inventories of landslides triggered by short rainfall events, whose timing is therefore known to within a few days (rainfall time series are available in the Supplement): first, landslides triggered in Hiroshima, Japan, by a heavy-rainfall event which took place from 28 June to 9 July 2018, which were mapped using a combination of drone and aerial imagery (inventory from The Association of Japanese Geographers, 2019). The majority of landslides triggered by this event are believed to have occurred during peaks in rainfall intensity on 6-7 July (Hashimoto et al, 2020).…”

Section: Case Studiesmentioning

confidence: 99%

Using Sentinel-1 radar amplitude time series to constrain the timings of individual landslides: a step towards understanding the controls on monsoon-triggered landsliding

Burrows

Marc²,

Rémy³

2022

Nat. Hazards Earth Syst. Sci.

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Abstract. Heavy-rainfall events in mountainous areas trigger destructive landslides, which pose a risk to people and infrastructure and significantly affect the landscape. Landslide locations are commonly mapped using optical satellite imagery, but in some regions their timings are often poorly constrained due to persistent cloud cover. Physical and empirical models that provide insights into the processes behind the triggered landsliding require information on both the spatial extent and the timing of landslides. Here we demonstrate that Sentinel-1 synthetic aperture radar amplitude time series can be used to constrain landslide timing to within a few days and present four techniques to accomplish this based on time series of (i) the difference in amplitude between the landslide and its surroundings, (ii) the spatial variability in amplitude between pixels within the landslide, and (iii) geometric shadows and (iv) geometric bright spots cast within the landslide. We test these techniques on three inventories of landslides of known timing, covering various settings and triggers, and demonstrate that a method combining them allows 20 %–30 % of landslides to be timed with an accuracy of 80 %. Application of this method could provide an insight into landslide timings throughout events such as the Indian summer monsoon, which triggers large numbers of landslides every year and has until now been limited to annual-scale analysis.

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Section: Case Studiesmentioning

confidence: 99%

Using Sentinel-1 radar amplitude time series to constrain the timings of individual landslides: a step towards understanding the controls on monsoon-triggered landsliding

Burrows

Marc²,

Rémy³

2022

Nat. Hazards Earth Syst. Sci.

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show abstract

“…First, an inventory of 543 landslides triggered in Hiroshima, Japan by a heavy rainfall event which took place from 28 June to 9 July 2018, which were mapped using a combination of drone and aerial imagery (inventory from The Association of Japanese Geographers, 2019). The majority of landslides triggered by this event are believed to have occurred during peaks in rainfall intensity on the 6-7 July (Hashimoto et al, 2020). Second, we used an inventory of 383 landslides triggered by Cyclone Idai in Zimbabwe between 15-19 March 2019.…”

Section: Case Study Eventsmentioning

confidence: 99%

Establishing the timings of individual rainfall-triggered landslides using Sentinel-1 satellite radar data

Burrows

Marc

Rémy

2022

Preprint

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Abstract. Heavy rainfall events in mountainous areas can trigger thousands of destructive landslides, which pose a risk to people and infrastructure and significantly affect the landscape. Landslide locations are typically mapped using optical satellite imagery, but in some regions their timings are often poorly constrained due to persistent cloud cover. Physical and empirical models that provide insights on the processes behind the triggered landsliding require information on both the spatial extent and timing of landslides. Here we demonstrate that Sentinel-1 SAR amplitude time series can be used to constrain landslide timing to within a few days and present three methods to accomplish this based on time series of: (i) the difference in amplitude between the landslide and its surroundings, (ii) the spatial variability of amplitude between pixels within the landslide, and (iii) geometric shadows cast within the landslide. We test these methods on three inventories of landslides of known timing, covering various settings and triggers, and demonstrate that, when used in combination, our methods allow 20 % of landslides to be timed with an accuracy of 80 %. This will allow multi-temporal landslide inventories to be generated for long rainfall events such as the Indian summer monsoon, which triggers large numbers of landslides every year and has until now been limited to annual-scale analysis.

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“…However, increasing sedimentation due to soil erosion has a negative impact on water quality and marine productivity (Ram and Terry 2016). Such erosion problems caused by mud ows and landslides triggered by these heavy seasonal precipitations is one of the major challenges that is currently faced in the western region of Japan (Al Sawaf and Kawanisi 2020; Hashimoto et al 2020;Tsuchida et al 2014).…”

Section: )mentioning

confidence: 99%

“…In 2018, however, heavy rains induced by the synchronization of the Baiu front with the Typhoon No. 7 from July 3rd to July 8th caused a tremendous damage to the areas in western Japan (Hashimoto et al 2020). These rainy events are projected to increase more in the future leading to increment in rive ow (Al Sawaf et al 2021; Higashino and Stefan 2019).…”

Section: Pentad Precipitation Plotsmentioning

confidence: 99%

Investigating rainfall-runoff and turbidly behavior during the rainy season in west of Japan

Sawaf

Kawanisi

Bahreinimotlagh³

2023

Preprint

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Understanding the recent variability in massive rainfall patterns is essential to provide a clear image about underlying hydrological processes that occur over a watershed scale. The main objective of this study is to investigate the variability of rainfall events in Western Japan as a result of climate change and examine the related runoff-turbidity dynamics during rainy season. To fulfill the research objectives, we investigated the changeability of the precipitation records in the Gōno River watershed for the last two decades and the related runoff-turbidity behavior during floods using the turbidity-discharge (T-Q) loops and quantified using an improved hysteresis index. The findings revealed a kind of intense rainfall periodicity of 3 ~ 4 years. In addition, spatial pentads analysis exhibited various intensities of accumulated precipitation suggesting that there is no specific spatial zone of extreme rainfall. Regarding the turbidity-discharge behavior, it was found that clockwise hysteresis patterns were induced by sediment sources from near channel areas, alternatively, anticlockwise pattens were produced due to soil erodibility from the nearby areas. Another interesting finding was a notable behavior of turbidity during floods such as “bursts” or “local peaks” may represent an earlier (or later) arrival of turbid waters from nearby distant sources at an upstream section as a result of an intense precipitation. One of the fundamental challenges in the quantification of hysteresis patterns is that there is no accepted definition on how to determine the start and the end of a flood event which may led to a bias in the quantification of these patterns.

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Hiroshima Prefecture geo-disasters due to Western Japan Torrential rainfall in July 2018

Cited by 23 publications

References 4 publications

Using Sentinel-1 radar amplitude time series to constrain the timings of individual landslides: a step towards understanding the controls on monsoon-triggered landsliding

Using Sentinel-1 radar amplitude time series to constrain the timings of individual landslides: a step towards understanding the controls on monsoon-triggered landsliding

Establishing the timings of individual rainfall-triggered landslides using Sentinel-1 satellite radar data

Investigating rainfall-runoff and turbidly behavior during the rainy season in west of Japan

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