A copy of Guangbo jiemu bao [Broadcast Program Report] was being passed from hand to hand among a group of young people eager to be the first to read the article introducing the program "What Is Revolutionary Love?" It said: "… Young friends, you are certainly very concerned about this problem'. So, we would like you to meet the young women workers Meng Xiaoyu and Meng Yamei and the older cadre Miss Feng. They are the three leading characters in the short story ‘The Place of Love.’ Through the description of the love lives of these three, the story induces us to think deeply about two questions that merit further examination.

This is How the Discussion Started

High resolution schemes for hyperbolic conservation laws

Soil Genesis and Classification

This paper relates landslide inventories to erosion rates and provides quantitative estimates of the landslide hazard associated with earthquakes. We do this by utilizing a three-parameter inverse-gamma distribution, which fits the frequency– area statistics of three substantially dcompleteT landslide-event inventories. A consequence of this general distribution is that a landslide-event magnitude mL=logNLT can be introduced, where NLT is the total number of landslides associated with the landslide event. Using this general distribution, landslide-event magnitudes mL can be obtained from incomplete landslide inventories, and the total area and volume of associated landslides, as well as the area and volume of the maximum landslides, can be directly related to the landslide-event magnitude. Using estimated recurrence intervals for three landslide events and the time span for two historical inventories, we estimate regional erosion rates associated with landslides as typically 0.1–2.5 mm year � 1 . We next give an empirical correlation between the earthquake magnitude, associated landslideevent magnitude, and the total volume of associated landslides. Using these correlations, we estimate that the minimum earthquake magnitudes that will generate landslides is M=4.3F0.4. Finally, using Gutenberg–Richter frequency-magnitude statistics for regional seismicity, we relate the intensity of seismicity in an area and the magnitude of the largest regional earthquakes to erosion rates. We find that typical seismically induced erosion rates in active subduction zones are 0.2–7 mm year � 1 and adjacent to plate boundary strike-slip fault zones are 0.01–0.7 mm year � 1 .

Landslides, Earthquakes, and Erosion

The glacial way of wearing away The rate at which glaciers erode landscapes is an important but poorly constrained relationship. Herman et al. tackle this issue by considering the Franz Josef alpine glacier in New Zealand. The amount of sediment piling up at the edge of the glacier provided erosion rates, whereas remote sensing allowed for simultaneous tracking of glacial motion. The result was a nonlinear relationship, suggesting that fast glaciers are much more effective at gouging landscapes. This could explain the paradox of why long-term erosion rates are so much lower in polar regions with more permanent glaciers. Science, this issue p. 193 Erosion rate and sliding velocity have a nonlinear relationship in the Franz Josef alpine glacier. Assessing the impact of glaciation on Earth’s surface requires understanding glacial erosion processes. Developing erosion theories is challenging because of the complex nature of the erosion processes and the difficulty of examining the ice/bedrock interface of contemporary glaciers. We demonstrate that the glacial erosion rate is proportional to the ice-sliding velocity squared, by quantifying spatial variations in ice-sliding velocity and the erosion rate of a fast-flowing Alpine glacier. The nonlinear behavior implies a high erosion sensitivity to small variations in topographic slope and precipitation. A nonlinear rate law suggests that abrasion may dominate over other erosion processes in fast-flowing glaciers. It may also explain the wide range of observed glacial erosion rates and, in part, the impact of glaciation on mountainous landscapes during the past few million years.

Erosion by an Alpine glacier

. Landscape evolution models (LEMs) allow the study of earth surface responses to changing climatic and tectonic forcings. While much effort has been devoted to the development of LEMs that simulate a wide range of processes, the numerical accuracy of these models has received less attention. Most LEMs use first-order accurate numerical methods that suffer from substantial numerical diffusion. Numerical diffusion particularly affects the solution of the advection equation and thus the simulation of retreating landforms such as cliffs and river knickpoints. This has potential consequences for the integrated response of the simulated landscape. Here we test a higher-order flux-limiting finite volume method that is total variation diminishing (TVD-FVM) to solve the partial differential equations of river incision and tectonic displacement. We show that using the TVD-FVM to simulate river incision significantly influences the evolution of simulated landscapes and the spatial and temporal variability of catchment-wide erosion rates. Furthermore, a two-dimensional TVD-FVM accurately simulates the evolution of landscapes affected by lateral tectonic displacement, a process whose simulation was hitherto largely limited to LEMs with flexible spatial discretization. We implement the scheme in TTLEM (TopoToolbox Landscape Evolution Model), a spatially explicit, raster-based LEM for the study of fluvially eroding landscapes in TopoToolbox 2.

/pdf/accurate-simulation-of-transient-landscape-evolution-by-14se2o5hz9.pdf

Accurate simulation of transient landscape evolution by eliminating numerical diffusion: the TTLEM 1.0 model

Landslide mobilization rates: A global analysis and model

http://dspace.ucuenca.edu.ec/bitstream/123456789/29201/1/documento.pdf

Transient river response, captured by channel steepness and its concavity

The stream power equation is commonly used to model river incision into bedrock. Although specific conditions allow an analytical approach, finite difference methods (FDMs) are most frequently used to solve this equation. FDMs inevitably suffer from numerical smearing which may affect their suitability for transient river incision modeling. We propose the use of a finite volume method (FVM) which is total variation diminishing (TVD) to simulate river incision in a more accurate way. The TVD_FVM is designed to simulate sharp discontinuities, making it very suitable to simulate river incision pulses. We show that the TVD_FVM is much better capable of preserving propagating knickpoints than FDMs, using Niagara Falls as an example. Comparison of numerical results obtained using the TVD_FVM with analytical solutions shows a very good agreement. Furthermore, the uncertainty associated with parameter calibration is dramatically reduced when the TVD_FVM is applied. The high accuracy of the TVD_FDM allows correct simulation of transient incision waves as a consequence of older uplift pulses. This implies that the TVD_FVM is much more suitable than FDMs to reconstruct regional uplift histories from current river profile morphology and to simulate river incision processes in general.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2014JF003376

Benjamin Campforts

Papers

Accurate simulation of transient landscape evolution by eliminating numerical diffusion: the TTLEM 1.0 model

Landslide mobilization rates: A global analysis and model

Transient river response, captured by channel steepness and its concavity

Keeping the edge: A numerical method that avoids knickpoint smearing when solving the stream power law

Simulating the mobility of meteoric 10Be in the landscape through a coupled soil-hillslope model (Be2D)