scholarly journals Topographic Evolution Involving Co-Seismic Landslide, Deformation, Long-Term Folding and Isostatic Rebound: A Case Study on the 2004 Chuetsu Earthquake

2021 ◽  
Vol 13 (6) ◽  
pp. 1073
Author(s):  
Jinghao Lei ◽  
Zhikun Ren ◽  
Takashi Oguchi ◽  
Peizhen Zhang ◽  
Shoichiro Uchiyama
Keyword(s):  
Hanging Wall ◽  
Volume Estimation ◽  
Catchment Scale ◽  
Epicentral Area ◽  
Landslide Volume ◽  
Digital Elevation ◽  
Geological Evolution ◽  
Seismically Induced Landslides ◽  
Seismic Landslide

Co-seismic landslide volume information is critical to understanding the role of strong earthquakes in topographic and geological evolution. The availability of both pre- and post-earthquake high-resolution digital elevation models (DEMs) provides us with the opportunity to develop a new approach to obtain robust landslide volume information. Here, we propose a method for landslide volume estimation and test it in the Chuetsu region, where a Mw 6.6 earthquake occurred in 2004. First, we align the DEMs by reconstructing the horizontal difference. Then, we quantitatively obtain the landslide volume in the epicentral area by differencing the pre- and post-earthquake DEMs. We convert the landslide volume into the distribution of average catchment-scale denudation and the resulting long-term crustal rebound. Our findings reveal that the Chuetsu earthquake mainly roughens the topography in the low-elevation Chuetsu region. Our results indicate that the preserved topography not only is due to the uplift caused by fault-related folding on the hanging wall of the Muikamachi fault but also undergoes erosion caused by seismically induced landslides and crustal rebound also modifies the topography in the long term. This study confirms that the differential DEM method is a valuable approach for quantitative analysis of topographic and geological evolution.

scholarly journals Topographic changes due to the 2004 Chuetsu thrusting earthquake in low mountain region

2019 ◽  
Author(s):  
Zhikun Ren ◽  
Takashi Oguchi ◽  
Peizhen Zhang ◽  
Shoichiro Uchiyama
Keyword(s):  
Scaling Laws ◽  
Catchment Scale ◽  
Volume Estimate ◽  
Epicentral Area ◽  
Quantitative Studies ◽  
Landslide Volume ◽  
Seismically Induced Landslides ◽  
Seismic Landslide ◽  
Topographic Evolution

Abstract. The co-seismic landslide volume information is critical to understanding the role of strong earthquake in topographic evolution. However, the co-seismic landslide volumes are mainly obtained using statistical scaling laws, which are not accurate enough for quantitative studies of the spatial pattern of co-seismically induced erosion and the topographic changes caused by the earthquakes. The availability of both pre- and post- earthquake high-resolution DEMs provide us the opportunity to try new approach to get robust landslide volume information. Here, we propose a new method in landslide volume estimate and tested it in Chuetsu region, where a Mw 6.6 earthquake occurred in 2004. Firstly, we align the DEMs by reconstructing the horizontal difference, then we quantitatively obtained the landslide volume in the epicentral area by differencing the pre- and post-earthquake DEMs. We convert the landslide volume into the distribution of average catchment-scale seismically induced denudation. Our results indicate the preserved topography is not only due to the uplifting caused by fault-related folding on the hangwall of Muikamachi fault, but also undergone erosion caused by the seismically induced landslides. Our findings reveal that Chuetsu earthquake mainly roughens the topography in the Chuetsu region of low elevation. This study also reveal that the differential DEM method is a valuable approach in analyzing landslide volume, as well as quantitative geomorphic analysis.

scholarly journals Beyond 2D inventories : synoptic 3D landslide volume calculation from repeat LiDAR data

2020 ◽  
Author(s):  
Thomas G. Bernard ◽  
Dimitri Lague ◽  
Philippe Steer
Keyword(s):  
Point Cloud ◽  
Volume Estimation ◽  
Airborne Lidar ◽  
Aerial Images ◽  
3D Point Cloud ◽  
Volume Calculation ◽  
Landslide Volume ◽  
Digital Elevation ◽  
Multi Temporal ◽  
Areal Mapping

Abstract. Efficient and robust landslide mapping and volume estimation is essential to rapidly infer landslide spatial distribution, to quantify the role of triggering events on landscape changes and to assess direct and secondary landslide-related geomorphic hazards. Many efforts have been made during the last decades to develop landslide areal mapping methods, based on 2D satellite or aerial images, and to constrain empirical volume-area (V-A) allowing in turn to offer indirect estimates of landslide volume. Despite these efforts, some major issues remain including the uncertainty of the V-A scaling, landslide amalgamation and the under-detection of reactivated landslides. To address these issues, we propose a new semi-automatic 3D point cloud differencing method to detect geomorphic changes, obtain robust landslide inventories and directly measure the volume and geometric properties of landslides. This method is based on the M3C2 algorithm and was applied to a multi-temporal airborne LiDAR dataset of the Kaikoura region, New Zealand, following the Mw 7.8 earthquake of 14 November 2016. We demonstrate that 3D point cloud differencing offers a greater sensitivity to detect small changes than a classical difference of DEMs (digital elevation models). In a small 5 km2 area, prone to landslide reactivation and amalgamation, where a previous study identified 27 landslides, our method is able to detect 1431 landslide sources and 853 deposits with a total volume of 908,055 ± 215,640 m3 and 1,008,626 ± 172,745 m3, respectively. This high number of landslides is set by the ability of our method to detect subtle changes and therefore small landslides with a carefully constrained lower limit of 20 m2 (90 % with A 

scholarly journals Assessment of Landslide-Induced Geomorphological Changes in Hítardalur Valley, Iceland, Using Sentinel-1 and Sentinel-2 Data

2020 ◽  
Vol 10 (17) ◽  
pp. 5848
Author(s):  
Zahra Dabiri ◽  
Daniel Hölbling ◽  
Lorena Abad ◽  
Jón Kristinn Helgason ◽  
Þorsteinn Sæmundsson ◽  
...  
Keyword(s):  
Significant Risk ◽  
Radar Data ◽  
Volume Estimation ◽  
Lake Area ◽  
Synthetic Aperture Radar Data ◽  
Landslide Volume ◽  
Digital Elevation ◽  
Hazard And Risk ◽  
Geomorphological Changes ◽  
Sentinel 2

Landslide mapping and analysis are essential aspects of hazard and risk analysis. Landslides can block rivers and create landslide-dammed lakes, which pose a significant risk for downstream areas. In this research, we used an object-based image analysis approach to map geomorphological features and related changes and assess the applicability of Sentinel-1 data for the fast creation of post-event digital elevation models (DEMs) for landslide volume estimation. We investigated the Hítardalur landslide, which occurred on the 7 July 2018 in western Iceland, along with the geomorphological changes induced by this landslide, using optical and synthetic aperture radar data from Sentinel-2 and Sentinel-1. The results show that there were no considerable changes in the landslide area between 2018 and 2019. However, the landslide-dammed lake area shrunk between 2018 and 2019. Moreover, the Hítará river diverted its course as a result of the landslide. The DEMs, generated by ascending and descending flight directions and three orbits, and the subsequent volume estimation revealed that—without further post-processing—the results need to be interpreted with care since several factors influence the DEM generation from Sentinel-1 imagery.

River Quality Models for Consent Setting in England and Wales

1989 ◽  
Vol 21 (8-9) ◽  
pp. 1015-1024 ◽  
Author(s):  
C. P. Crockett ◽  
R. W. Crabtree ◽  
I. D. Cluckie
Keyword(s):  
River System ◽  
Quality Model ◽  
Catchment Scale ◽  
Quality Models ◽  
England And Wales ◽  
Future Developments ◽  
Statistical Framework ◽  
River Quality ◽  
National Approach

In England and Wales the placing of effluent discharge consents within a statistical framework has led to the development of a new hybrid type of river quality model. Such catchment scale consent models have a stochastic component for the generation of model inputs and a deterministic component to route them through the river system. This paper reviews and compares the existing approaches for consent modelling used by various Water Authorities. A number of possible future developments are suggested including the potential need for a national approach to the review and setting of long term consents.

scholarly journals Integrated Impact Assessment for Sustainable Hydropower Planning in the Vjosa Catchment (Greece, Albania)

2021 ◽  
Vol 13 (3) ◽  
pp. 1514
Author(s):  
Rebecca Peters ◽  
Jürgen Berlekamp ◽  
Ana Lucía ◽  
Vittoria Stefani ◽  
Klement Tockner ◽  
...  
Keyword(s):  
Impact Assessment ◽  
Planning Process ◽  
Renewable Energy Sources ◽  
Decision Makers ◽  
Catchment Scale ◽  
Northern Greece ◽  
Hydropower Plants ◽  
Hydropower Planning

Mitigating climate change, while human population and economy are growing globally, requires a bold shift to renewable energy sources. Among renewables, hydropower is currently the most economic and efficient technique. However, due to a lack of impact assessments at the catchment scale in the planning process, the construction of hydropower plants (HPP) may have unexpected ecological, socioeconomic, and political ramifications in the short and in the long term. The Vjosa River, draining parts of Northern Greece and Albania, is one of the few predominantly free-flowing rivers left in Europe; at the same time its catchment is identified an important resource for future hydropower development. While current hydropower plants are located along tributaries, planned HPP would highly impact the free-flowing main stem. Taking the Vjosa catchment as a case study, the aim of this study was to develop a transferable impact assessment that ranks potential hydropower sites according to their projected impacts on a catchment scale. Therefore, we integrated established ecological, social, and economic indicators for all HPP planned in the river catchment, while considering their capacity, and developed a ranking method based on impact categories. For the Vjosa catchment, ten hydropower sites were ranked as very harmful to the environment as well as to society. A sensitivity analysis revealed that this ranking is dependent upon the selection of indicators. Small HPP showed higher cumulative impacts than large HPP, when normalized to capacity. This study empowers decision-makers to compare both the ranked impacts and the generated energy of planned dam projects at the catchment scale.

scholarly journals MATLAB Virtual Toolbox for Retrospective Rockfall Source Detection and Volume Estimation Using 3D Point Clouds: A Case Study of a Subalpine Molasse Cliff

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 75
Author(s):  
Dario Carrea ◽  
Antonio Abellan ◽  
Marc-Henri Derron ◽  
Neal Gauvin ◽  
Michel Jaboyedoff
Keyword(s):  
Point Cloud ◽  
Natural Hazard ◽  
Point Clouds ◽  
Volume Estimation ◽  
Natural Phenomena ◽  
Frequency Distributions ◽  
Erosion Rates ◽  
3D Point Clouds

The use of 3D point clouds to improve the understanding of natural phenomena is currently applied in natural hazard investigations, including the quantification of rockfall activity. However, 3D point cloud treatment is typically accomplished using nondedicated (and not optimal) software. To fill this gap, we present an open-source, specific rockfall package in an object-oriented toolbox developed in the MATLAB® environment. The proposed package offers a complete and semiautomatic 3D solution that spans from extraction to identification and volume estimations of rockfall sources using state-of-the-art methods and newly implemented algorithms. To illustrate the capabilities of this package, we acquired a series of high-quality point clouds in a pilot study area referred to as the La Cornalle cliff (West Switzerland), obtained robust volume estimations at different volumetric scales, and derived rockfall magnitude–frequency distributions, which assisted in the assessment of rockfall activity and long-term erosion rates. An outcome of the case study shows the influence of the volume computation on the magnitude–frequency distribution and ensuing erosion process interpretation.

A model of long-term catchment-scale nitrate transport in a UK Chalk catchment

2019 ◽  
pp. 179-189
Author(s):  
N.J.K. Howden ◽  
S.A. Mathias ◽  
M.J. Whelan ◽  
T.P. Burt ◽  
F. Worrall
Keyword(s):  
Nitrate Transport ◽  
Catchment Scale

scholarly journals The volume of left atrium measured by multi-detector computed tomography can predict of long term outcome in catheter ablation of atrial fibrillation

2021 ◽  
Vol 22 (Supplement_3) ◽  
Author(s):  
YR Kim
Keyword(s):  
Computed Tomography ◽  
Atrial Fibrillation ◽  
Catheter Ablation ◽  
Left Atrium ◽  
Volume Estimation ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Group 2 ◽  
Group 1

Abstract Funding Acknowledgements Type of funding sources: None. Background This study aimed to identify the volume left atrium (LA) and left atrial appendage (LAA) calculated by multidetector computed tomography (MDCT) is related to the long term out come of radiofrequency catheter ablation (RFCA) for atrial fibrillation(AF). Methods We analyzed data from 99 consecutive patients who referred for RFCA due to drug-refractory symptomatic AF (age 56 ± 10 years; 74% men; 64% paroxysmal AF). Prior to the procedure, all patients underwent ECG-gated 128 channels MDCT scan for assessment for pulmonary vein  anatomy, LA and LAA volume estimation, and electro-anatomical mapping integration.  Results The volume of LA and LAA calculated by CT was 142.6 ± 32.2 mL and 14.7 ± 6.0 mL, respectively. LA volume was smaller in paroxysmal AF(PAF) than persistent AF(PeAF) (133.9 ± 29.3 mL vs. 158.0 ± 31.4 mL, p < 0.0001) but  LAA volume was not significantly different between PAF and PeAF(13.9 ± 5.0 mL vs. 16.3 ± 7.3 mL, p = 0.09). Patients were classified into 2 groups by the LA volume of 160mL; group 1  (LA volume < 160mL,n = 73) and group 2 (LA volume ≥160mL, n = 26). After a mean follow up 12.6 ± 5.3 months, 78.8% of the patients maintained sinus rhythm after the index ablation. AF free survival was significantly greater in group  1 than group 2 (84.9% vs. 61.5% p = 0.017). No relationship was found between LAA volume and the outcome of RFCA. Multivariate analysis showed that the LA volume >160mL was an independent predictor of arrhythmia-free after ablation (Hazard ration 2.55, 95% confidential interval 1.02-6.35, p = 0.045) Conclusion Higher LA volume is independent risk factor for AF recurrence after RFCA but not LAA volume. The LA volume quickly assessed by MDCT could be a good predictor of long term recurrence after AF ablation.

Modelling long-term diffuse nitrate pollution at the catchment-scale: Data, parameter and epistemic uncertainty

2011 ◽  
Vol 403 (3-4) ◽  
pp. 337-351 ◽  
Author(s):  
N.J.K. Howden ◽  
T.P. Burt ◽  
S.A. Mathias ◽  
F. Worrall ◽  
M.J. Whelan
Keyword(s):  
Epistemic Uncertainty ◽  
Nitrate Pollution ◽  
Catchment Scale ◽  
Scale Data
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