SAR and optical images correlation illuminates post-seismic landslide motion after the Mw 7.8 Gorkha earthquake (Nepal)

Lacroix, Pascal; Gavillon, Théo; Bouchant, Clément; Lavé, Jérôme; Mugnier, Jean‐Louis; Dhungel, Samir; Vernier, Flavien

doi:10.1038/s41598-022-10016-2

Cited by 14 publications

(34 citation statements)

References 53 publications

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“…La Sorbella landslide (Italy), in turn, did not show any measurable increase in activity after coseismic displacements of 0.3-0.8 mm recorded during three earthquakes 13,14 . This large variation in the ratio between coseismic and postseismic motions has also been observed in various landslides affected by the Gorkha earthquake in Nepal 9 .…”

supporting

confidence: 67%

“…Of particular interest is the response to seismic shaking of active slow-moving landslides, which pose a serious threat to people and infrastructure [4][5][6][7][8] . Observations of such landslides reveal a wide range of earthquake related displacements, with surprisingly poor correlation between coseismic and postseismic motion 9 . For instance, the relatively small coseismic displacements (1-2 cm) of the Maca landslide (Peru) were followed by periods of increased velocities for about one month, resulting in three times greater cumulative displacements 10,11 .…”

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confidence: 99%

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Mechanics of coseismic and postseismic acceleration of active landslides

Kohler

Puzrin

2023

Commun Earth Environ

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Active slow-moving landslides exhibit very different coseismic and postseismic behaviour. Whereas some landslides do not show any postseismic acceleration, there are many that experience an increased motion in the days to weeks following an earthquake. The reason for this behaviour remains debated and the underlying mechanisms are only partially understood. In recent years, it has been suggested that postseismic acceleration is caused by excess pore water pressures generated outside of the shear zone during seismic shaking, with their subsequent diffusion into the shear zone. Here we show that this hypothesis is indeed plausible and hydro-mechanically consistent by using a basic rate-dependent physical landslide model. Our simulations provide insight into the landslide behaviour in response to seismic shaking and its main controlling parameters: preseismic landslide velocity, rate-dependency of soil strength in the shear zone, hydro-mechanical characteristics of the adjacent soil layers and the earthquake intensity.

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supporting

confidence: 67%

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confidence: 99%

Mechanics of coseismic and postseismic acceleration of active landslides

Kohler

Puzrin

2023

Commun Earth Environ

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“…Such approach is not uncommon as previous studies have also utilised the LOS velocity for identifying active hillslopes (Bayer et al, 2018;Bekaert et al, 2020;Cheaib et al, 2022;Lacroix et al, 2022).…”

Section: Limitationsmentioning

confidence: 99%

“…However, owing to the high computational requirement of TS-InSAR techniques, regional scale analyses, in particular, associated with earthquakes, are still rare. For instance, Lacroix et al (2022) revealed the lagged initiations and post-seismic relaxations of slow-moving landslides in the area hit by the 2015 Gorkha earthquake using Sentinel-1 SAR data. During this post-seismic relaxation phase, slowmoving hillslopes were found to have accelerating deformation mainly because of groundwater transmission.…”

Section: Introductionmentioning

confidence: 99%

Revealing the hillslope response to earthquake legacy effect using time series InSAR

Sãdhasivam¹,

Chang²,

Tanyaş³

2023

Preprint

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Strong earthquakes are not only able to change the earth's surface processes by triggering a large population of coseismic landslides but also by influencing hillslope deformation rates in post-seismic periods. An increase in post-seismic hillslope deformation rates could also be linked to a change in post-seismic landslide hazard level and, thus, could be exploited to better assess post-seismic landslide risk in a given area. However, variations in hillslope deformations from pre- to post-seismic phases have rarely been examined for strong earthquakes. This paper examines pre- and post-seismic hillslope deformations, from 2014 to 2018, for a large area (~2,300 km2) affected by the 2016 Mw7.8 Kaikōura earthquake using time series Interferometric Synthetic Aperture Radar (InSAR) techniques. To consistently analyze the entirety of the area from pre- to post-seismic phases, we aggregate InSAR-derived deformations for geomorphologically meaningful landscape partitions called Slope Units. We further examine the aggregated data through the hillslope deformation scheme, which we propose as a method to systematically identify the variations in post-seismic hillslope deformation trends. In this context, we label newly activated, uninterruptedly deforming, and stabilized hillslopes in the post-seismic phase. Our results show an ~130% increase in mean annual line-of-sight velocity after the earthquake. Overall, the areas affected by larger ground shaking show higher post-seismic deformations, which highlights the importance of the earthquake legacy effect as a factor controlling post-seismic hillslope deformations.

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“…Optical images conform to human vision, but are susceptible to objective factors such as cloud interference [2], whereas SAR images are immune to the imaging defects of optical images and have the advantages of all-weather acquisition, a long line of sight, and some level of penetration capability. Therefore, the fusion of optical and SAR images is widely used in pattern recognition [3], change detection [4], and landslide recognition [5]. However, a prerequisite for the fusion of SAR and optical images is high-accuracy matching.…”

Section: Introductionmentioning

confidence: 99%

A Dual-Generator Translation Network Fusing Texture and Structure Features for SAR and Optical Image Matching

Nie

Tang

et al. 2022

Remote Sensing

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The matching problem for heterologous remote sensing images can be simplified to the matching problem for pseudo homologous remote sensing images via image translation to improve the matching performance. Among such applications, the translation of synthetic aperture radar (SAR) and optical images is the current focus of research. However, the existing methods for SAR-to-optical translation have two main drawbacks. First, single generators usually sacrifice either structure or texture features to balance the model performance and complexity, which often results in textural or structural distortion; second, due to large nonlinear radiation distortions (NRDs) in SAR images, there are still visual differences between the pseudo-optical images generated by current generative adversarial networks (GANs) and real optical images. Therefore, we propose a dual-generator translation network for fusing structure and texture features. On the one hand, the proposed network has dual generators, a texture generator, and a structure generator, with good cross-coupling to obtain high-accuracy structure and texture features; on the other hand, frequency-domain and spatial-domain loss functions are introduced to reduce the differences between pseudo-optical images and real optical images. Extensive quantitative and qualitative experiments show that our method achieves state-of-the-art performance on publicly available optical and SAR datasets. Our method improves the peak signal-to-noise ratio (PSNR) by 21.0%, the chromatic feature similarity (FSIMc) by 6.9%, and the structural similarity (SSIM) by 161.7% in terms of the average metric values on all test images compared with the next best results. In addition, we present a before-and-after translation comparison experiment to show that our method improves the average keypoint repeatability by approximately 111.7% and the matching accuracy by approximately 5.25%.

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SAR and optical images correlation illuminates post-seismic landslide motion after the Mw 7.8 Gorkha earthquake (Nepal)

Cited by 14 publications

References 53 publications

Mechanics of coseismic and postseismic acceleration of active landslides

Mechanics of coseismic and postseismic acceleration of active landslides

Revealing the hillslope response to earthquake legacy effect using time series InSAR

A Dual-Generator Translation Network Fusing Texture and Structure Features for SAR and Optical Image Matching

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