The mechanics of landslide mobility with erosion

AbstractErosion can significantly increase the destructive power of a landslide by amplifying its volume, mobility and impact force. The threat posed by an erosive landslide is linked to its mobility. No mechanical condition has yet been presented for when, how and how much energy erosive landslides gain or lose. Here, we pioneer a mechanical model for the energy budget of erosive landslides that controls enhanced or reduced mobility. Inertia is related to an entrainment velocity, is a fundamentally new understanding. This ascertains the true inertia of erosive landslides, making a breakthrough in correctly determining the landslide mobility. Erosion velocity, which regulates the energy budget, determines the enhanced or reduced mobility. Newly developed energy generator offers the first-ever mechanical quantification of erosional energy and a precise description of mobility. This addresses the long-standing question of why many erosive landslides generate higher mobility, while others reduce mobility. We demonstrate that erosion and entrainment are different processes. Landslides gain energy and enhance mobility if the erosion velocity exceeds the entrainment velocity. Energy velocity delineates distinct excess energy regimes. Newly introduced mobility scaling and erosion number deliver the explicit measure of mobility. Presented dynamical equations correctly include erosion induced net momentum production.

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The Mechanics of Landslide Mobility with Erosion

10.5194/egusphere-egu21-14683 ◽

2021 ◽

Author(s):

Shiva P. Pudasaini ◽

Michael Krautblatter

Keyword(s):

Energy Budget ◽

Dominant Role ◽

Momentum Balance ◽

Dynamical Equations ◽

Entrainment Velocity ◽

Clear Cut ◽

Landslide Mobility ◽

Mechanism Of Landslide ◽

Reduced Mobility ◽

Deposition Morphology

<p>Erosion can dramatically change the dynamics and deposition morphology and escalate the destructive power of a landslide by rapidly amplifying its volume, turning it into a catastrophic event. Mobility is the direct measure of the thread posed by an erosive landslide as it plays a dominant role in controlling the enormous impact energy. However, no clear-cut mechanical condition has been presented so far for when and how the erosive landslide gains or loses energy resulting in enhanced or reduced mobility. We pioneer a mechanical model for the energy budget of an erosive landslide that delineates the enhanced or reduced mobility. A fundamentally new understanding is that the increased inertia due to the increased mass is not related to the landslide velocity, but it is associated with the distinctly different entrainment velocity emerging from the inertial frame of reference. The true inertia can be much less than incorrectly proposed previously. We eliminate the existing erroneous perception and make a breakthrough in correctly determining the mobility of the erosive landslide. We reveal that the erosion velocity plays an outstanding role in appropriately determining the energy budget of the erosive landslide. Crucially, whether the erosion related mass flow mobility will be enhanced, reduced or remains unaltered depends exclusively on whether the newly constructed energy generator is positive, negative or zero. This provides a first-ever explicit mechanical quantification of the state of energy, and thus, the precise description of mobility. This becomes a game-changer and fully addresses the long-standing scientific question of why and when some erosive landslides have higher mobility, while others have their mobility reduced. By introducing three important novel mechanical concepts: erosion-velocity, entrainment-velocity and energy-velocity, we demonstrate that the erosion and entrainment are essentially different processes. With this, we draw a central inference: that the landslide gains energy and enhances its mobility if the erosion velocity is greater than the entrainment velocity. The energy velocity delineates the three excess energy regimes: positive, negative and zero. We establish a mechanism of landslide-propulsion that emerges from the net momentum production, providing the erosion-thrust to the landslide. Analytically obtained velocity quantifies the effect of erosion in landslide mobility and indicates the fact that erosion can have the major control on the landslide dynamics. We have also presented a full set of dynamical equations in conservative form in which the momentum balance correctly includes the erosion induced change in inertia and the momentum production. This is a great advancement in legitimate simulation of landslide motion with erosion.</p>

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Application of Modified Bloch Waves to Image Analysis of Extended Linear Defects

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005202x ◽

1974 ◽

Vol 32 ◽

pp. 402-403

Author(s):

S. Nakahara ◽

D. M. Maher

Keyword(s):

Image Analysis ◽

Computational Approach ◽

Dislocation Loops ◽

Plane Wave Expansion ◽

Dynamical Equations ◽

Bloch Waves ◽

Linear Defects ◽

Imperfect Crystal ◽

Localized Defects ◽

Defective Crystals

Since Head first demonstrated the advantages of computer displayed theoretical intensities from defective crystals, computer display techniques have become important in image analysis. However the computational methods employed resort largely to numerical integration of the dynamical equations of electron diffraction. As a consequence, the interpretation of the results in terms of the defect displacement field and diffracting variables is difficult to follow in detail. In contrast to this type of computational approach which is based on a plane-wave expansion of the excited waves within the crystal (i.e. Darwin representation ), Wilkens assumed scattering of modified Bloch waves by an imperfect crystal. For localized defects, the wave amplitudes can be described analytically and this formulation has been used successfully to predict the black-white symmetry of images arising from small dislocation loops.

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Motility of leukemic lymphocytes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159382 ◽

1990 ◽

Vol 48 (3) ◽

pp. 368-369

Author(s):

Manoj Raje ◽

Karvita B. Ahluwalia

Keyword(s):

Quantitative Data ◽

Laser Doppler Velocimetry ◽

Acute Lymphocytic Leukemia ◽

Lymphocytic Leukemia ◽

Cellular Space ◽

Differentiated Cells ◽

Poorly Differentiated ◽

Solid Tissues ◽

Well Differentiated ◽

Reduced Mobility

In Acute Lymphocytic Leukemia motility of lymphocytes is associated with dissemination of malignancy and establishment of metastatic foci. Normal and leukemic lymphocytes in circulation reach solid tissues where due to in adequate perfusion some cells get trapped among tissue spaces. Although normal lymphocytes reenter into circulation leukemic lymphocytes are thought to remain entrapped owing to reduced mobility and form secondary metastasis. Cell surface, transmembrane interactions, cytoskeleton and level of cell differentiation are implicated in lymphocyte mobility. An attempt has been made to correlate ultrastructural information with quantitative data obtained by Laser Doppler Velocimetry (LDV). TEM of normal & leukemic lymphocytes revealed heterogeneity in cell populations ranging from well differentiated (Fig. 1) to poorly differentiated cells (Fig. 2). Unlike other cells, surface extensions in differentiated lymphocytes appear to originate by extrusion of large vesicles in to extra cellular space (Fig. 3). This results in persistent unevenness on lymphocyte surface which occurs due to a phenomenon different from that producing surface extensions in other cells.

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