scholarly journals A Rainfall Intensity-Duration Threshold for Mass Movement in Badulla, Sri Lanka

2017 ◽  
Vol 05 (12) ◽  
pp. 135-152 ◽  
Author(s):  
E. N. C. Perera ◽  
D. T. Jayawardana ◽  
Pathmakumara Jayasinghe
Keyword(s):  
Sri Lanka ◽  
Rainfall Intensity ◽  
Mass Movement ◽  
Duration Threshold

scholarly journals A remote-sensing-based intensity–duration threshold, Faifa Mountains, Saudi Arabia

2019 ◽  
Vol 19 (6) ◽  
pp. 1235-1249 ◽  
Author(s):  
Sita Karki ◽  
Mohamed Sultan ◽  
Saleh Alsefry ◽  
Hassan Alharbi ◽  
Mustafa Kemal Emil ◽  
...  
Keyword(s):  
Field Data ◽  
Mass Movement ◽  
Google Earth ◽  
Archival Data ◽  
Backscatter Coefficient ◽  
Duration Threshold ◽  
Radar Imagery ◽  
Temporal And Spatial ◽  
Precipitation Events ◽  
Red Sea Hills

Abstract. Construction of intensity–duration (ID) thresholds and early-warning and nowcasting systems for landslides (EWNSLs) are hampered by the paucity of temporal and spatial archival data. This work represents significant steps towards the development of a prototype EWNSL to forecast and nowcast landslides over the Faifa Mountains in the Red Sea Hills. The developed methodologies rely on readily available, temporal, archival Google Earth and Sentinel-1A imagery, precipitation measurements, and limited field data to construct an ID threshold for Faifa. The adopted procedures entail the generation of an ID threshold to identify the intensity and duration of precipitation events that cause landslides in the Faifa Mountains, and the generation of pixel-based ID curves to identify locations where movement is likely to occur. Spectral and morphologic variations in temporal Google Earth imagery following precipitation events were used to identify landslide-producing storms and generate the Faifa ID threshold (I =4.89D−0.65). Backscatter coefficient variations in radar imagery were used to generate pixel-based ID curves and identify locations where mass movement is likely to occur following landslide-producing storms. These methodologies accurately distinguished landslide-producing storms from non-landslide-producing ones and identified the locations of these landslides with an accuracy of 60 %.

scholarly journals Characteristics of landslides in unwelded pyroclastic flow deposits, southern Kyushu, Japan

2015 ◽  
Vol 3 (10) ◽  
pp. 6351-6378 ◽  
Author(s):  
M. Yamao ◽  
R. C. Sidle ◽  
T. Gomi ◽  
F. Imaizumi
Keyword(s):  
Pyroclastic Flow ◽  
Slope Failure ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Antecedent Rainfall ◽  
Rainfall Characteristics ◽  
Antecedent Conditions ◽  
Duration Threshold ◽  
Different Types

Abstract. We investigated 184 landslides that occurred in unwelded pyroclastic flow deposits (Shirasu) on southern Kyushu Island, Japan, that included detailed data on the rainfall characteristics and the timing of slope failure. Localized rainfall intensity, antecedent rainfall, and topography affected the hydrologic processes that triggered landslides. Antecedent rainfall (adjusted for evapotranspiration losses) for large (> 200 mm) storms that triggered landslides was much lower than for smaller (≤ 200 mm) storms. Mean storm intensity and antecedent 7 day rainfall (API7) thresholds of > 5 mm h-1 and ≤ 30 mm (or API30 ≤ 60 mm), respectively, were useful to identify landslides triggered by rapid pore water pressure response, especially for shorter (< 20 h) duration events. During smaller storms with lower intensity, landslides are likely affected by a combined increase in soil weight and loss of suction when API30 ≥ 150 mm; simulations indicated that these weight and suction changes due to rainfall accumulation decreased factor of safety in steep Shirasu slopes, but did not necessarily trigger the landslides. All but two of the 21 landslides that plotted below a general rainfall intensity-duration threshold for landslide initiation had API30 values > 235 mm, indicating that they were highly influenced by the combined effects of the accumulated weight of rainfall and loss of suction. Our findings show that both event rainfall characteristics and antecedent conditions affect the hydrogeomorphic processes that trigger different types of landslides in Shirasu. This knowledge and the thresholds we have identified are useful for predicting the occurrence of different types of landslides in Shirasu deposits and improving sediment disaster prevention practices, including real-time warning systems.

A physics-based model to derive rainfall intensity-duration threshold for debris flow

Geomorphology ◽  
2020 ◽  
Vol 351 ◽  
pp. 106930 ◽  
Author(s):  
S.J. Zhang ◽  
C.X. Xu ◽  
F.Q. Wei ◽  
K.H. Hu ◽  
H. Xu ◽  
...  
Keyword(s):  
Debris Flow ◽  
Rainfall Intensity ◽  
Duration Threshold

Effect of Precipitation Characteristics on Spatial and Temporal Variations of Landslide in Kermanshah Province in Iran

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Safieh Javadinejad ◽  
Rebwar Dara ◽  
Forough Jafary
Keyword(s):  
Rainfall Intensity ◽  
Elevation Gradient ◽  
Mass Movement ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Temporal Variations ◽  
Topographic Map ◽  
Maximum Rainfall ◽  
Average Rainfall ◽  
Moving Points

Landslide can be defined as the mass movement of sloping slopes under the influence of mass gravity and its stimuli such as earthquakes, floods and flood plains. This phenomenon is one of the natural hazards that every year causes a lot of financial and financial losses in mountainous, rain-fed and seismic areas. Detection of time and the magnitude of landslides are necessary to understand the causes of landslide and to warn potential hazards. In this research, the amount of landslide displacement in Kermanshah province was evaluated by the characteristics of rainfall. To this end, a network of fixed points in and out of the slipping mass of 20 points was created to monitor the amount of displacement on different slip load users and the amount of displacement of each point in 5 time intervals using the Global Positioning System for two-dimensional GPS measurement. The results of the 511-day follow-up showed that the total horizontal displacement of the moving points in the 5 intervals measured at 1658 mm has a monthly displacement rate of 112 mm. Also, the total vertical displacement of moving points at the same time is 899 mm, with a monthly movement rate of 71 mm. Then, precipitation variances such as rainfall, rainfall, precipitation duration, maximum rainfall intensity in the intervals of 10, 20, 30 and 60 minutes and the average rainfall intensity were calculated and extracted for each of the 5 time periods. The drawing of the vectors of points on the topographic map of the area indicated that the direction of mass movement is in the direction of elevation gradient of the region. The results showed that only the precipitation severity with the landslide had a good correlation. The landslide movement had the highest correlation with average rainfall intensity (R = 0.85) and with maximum 30 minutes rainfall (R = 0.67), respectively, and other rainfall characteristics like amount, duration, and type of rainfall had not significantly correlated with movement of landslides.

Rainfall intensity in geomorphology: Challenges and opportunities

2020 ◽  
pp. 030913332096789
Author(s):  
David Dunkerley
Keyword(s):  
Land Surface ◽  
Rainfall Intensity ◽  
Explanatory Power ◽  
Mass Movement ◽  
Soil Surface ◽  
Rainfall Simulation ◽  
Natural Rainfall ◽  
Challenges And Opportunities ◽  
Short Time ◽  
Geomorphic Processes

Rainfall arrival at the land surface drives or influences many geomorphic processes. These range from the mechanisms through which vegetation transforms rain into erosive gravity drops or stemflow, infiltration and water partitioning at the soil surface, the drop-impact sealing of soil surfaces, splash, sheet, and gully erosion, and triggering of the various forms of mass movement including landslides and debris flows. Rainfall intensity is a key influence on many of these mechanisms but is not a straightforward parameter to quantify, partly owing to the customary aggregation of rainfall data to hourly or other clock-time totals. This aggregation conceals intensity fluctuations including erosive ‘intensity bursts’ as well as the intermittency of rainfall. Nevertheless, much research shows that rainfall intensity over short time periods – 10–30 minutes – has great explanatory power. Much of our understanding of the influence of rainfall intensity is based on rainfall simulation experiments, but the value of the findings is limited because simulation is normally carried out using a high and constant rainfall intensity, quite unlike natural rainfall. This has limited our ability to build an understanding of the other important aspects of rainfall intensity, including, critically, its time variation and changed character among different environments – arid, temperate, or tropical. Thus, significant challenges and opportunities remain in the exploration of rainfall intensity in relation to geomorphology and geomorphic processes.

scholarly journals Landslide Hazard Zonation from a GIS Perspective and Urban Planning Solutions in Central –Division of Fiji Islands

2019 ◽  
Vol 8 (12S) ◽  
pp. 352-361
Keyword(s):  
Rainfall Intensity ◽  
Mass Movement ◽  
Potential Zone ◽  
Hazard Zonation ◽  
Landslide Hazard Zonation ◽  
Gis And Remote Sensing ◽  
Central Division ◽  
Fiji Islands ◽  
Remote Sensing Techniques ◽  
Upper Slope

As is a characteristic of rainfall-induced surficial landslides, the mass movement occurred where the landform or configuration of the bedrock surface facilitated the concentration of slope water. More than half of the landslides originated in slope depressions or drainage lines, with initial failure taking place on an upper slope, ridge or summit. The present study aims at assessing the rainfall intensity, site-soil-geology and seismicity of the central division of Viti Levu, Fiji Islands using the GIS and remote sensing techniques. Rainfall intensity, Site-soilgeology, geomorphology and SRTM DEM data were the main sources of layers used to carry out such analysis using the Frequency Ratio methodology and ArcGIS Multi-Criteria Analysis (MCA). The final result of Land Slide Potential Zone (LSPZ) indicates the ‘low’, ‘moderate’ and ‘high’ zones. The result presents a readable map for people to simply identify their state of vulnerability within the study area. Thus, this research will assist professionals such as urban planners, engineers and legislators to implement sustainable developments whilst reducing the risks of disasters.

scholarly journals Laboratory experiments on rainfall-induced flowslide from pore pressure and moisture content measurements

2015 ◽  
Vol 3 (2) ◽  
pp. 1575-1613 ◽  
Author(s):  
M. R. Hakro ◽  
I. S. H. Harahap
Keyword(s):  
Moisture Content ◽  
Pore Pressure ◽  
Sandy Soil ◽  
Laboratory Experiments ◽  
Slope Failure ◽  
Rainfall Intensity ◽  
Mass Movement ◽  
Sudden Increase ◽  
Antecedent Moisture ◽  
Type Of Failure

Abstract. During or immediately after rainfall many slope failures have been observed. The slope failure occurred due to rainfall infiltration that rapidly increase the pore pressure and trigger the slope failure. Numerous studies have been conducted to investigate the rainfall-induced slope failure, but the mechanism of slope failure is still not well clarified. To investigate mechanism of rainfall-induced slope failure laboratory experiments have been conducted in flume. The slope was prepared with sandy soil in flume with constant inclination of 45°, because most of rainfall-induced slope failure occurred in sandy soil and on steep slope. The hydrological parameters such as pore pressure and moisture content were measured with piezometers and advanced Imko TDRs respectively. The slope failure occurred due to increase in moisture content and rise in pore pressure. During the flowslide type of slope failure the sudden increase in pore pressure was observed. The higher moisture content and pore pressure was at the toe of the slope. The pore pressure was higher at the toe of the slope and smaller at the upper part of the slope. After the saturation the run-off was observed at the toe of the slope that erodes the toe and forming the gullies from toe to upper part of the slope. In the case antecedent moisture conditions the moisture content and the pore pressure increased quickly and producing the surface runoff at the horizontal part of the slope. The slope having less density suffer from flowslide type of the failure, however in dense slope no major failure was occurred even at higher rainfall intensity. The antecedent moisture accompanied with high rainfall intensity also not favors the initiation of flowslide in case of dense slope. The flowslide type of failure can be avoided by controlling the density of soil slope. Knowing such parameters that controls the large mass movement helpful in developing the early warning system for flowslide type of failure.

scholarly journals Characteristics of landslides in unwelded pyroclastic flow deposits, southern Kyushu, Japan

2016 ◽  
Vol 16 (2) ◽  
pp. 617-627 ◽  
Author(s):  
M. Yamao ◽  
R. C. Sidle ◽  
T. Gomi ◽  
F. Imaizumi
Keyword(s):  
Pyroclastic Flow ◽  
Slope Failure ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Rainfall Characteristics ◽  
Hydrologic Processes ◽  
Antecedent Precipitation ◽  
Duration Threshold ◽  
Different Types

Abstract. We investigated 184 landslides that occurred in unwelded pyroclastic flow deposits (Shirasu) on southern Kyushu Island, Japan, that included detailed data on the rainfall characteristics and the timing of slope failure. Localized rainfall intensity, antecedent precipitation index (API), and topography affected the hydrologic processes that triggered landslides. API (adjusted for evapotranspiration losses) for large ( >  200 mm) storms that triggered landslides was much lower than for smaller ( ≤  200 mm) storms. Mean storm intensity and 7-day API (API7) thresholds of  >  5 mmh−1 and  ≤  30 mm (or API30 ≤  60 mm), respectively, were useful to identify landslides triggered by rapid pore water pressure response, especially for shorter ( <  20 h) duration events. During smaller storms with lower intensity, landslides are likely affected by a combined increase in soil weight and loss of suction when API30 ≥  150 mm; simulations indicated that these weight and suction changes due to rainfall accumulation decreased the factor of safety in steep Shirasu slopes, but did not necessarily trigger the landslides. Most of the landslides that were plotted below a general rainfall intensity–duration threshold for landslide initiation occurred during smaller storms with API30 values  >  200 mm, indicating that they were highly influenced by the combined effects of the accumulated weight of rainfall and loss of suction. Our findings show that both event rainfall characteristics and API affect the hydrogeomorphic processes that trigger different types of landslides in Shirasu. This knowledge and the thresholds we have identified are useful for predicting the occurrence of different types of landslides in unwelded Shirasu deposits and improving sediment disaster prevention practices, including real-time warning systems.

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