Gravity-driven groundwater flow and slope failure potential: 2. Effects of slope morphology, material properties, and hydraulic heterogeneity

1992 ◽  
Vol 28 (3) ◽  
pp. 939-950 ◽  
Author(s):  
Mark E. Reid ◽  
Richard M. Iverson
2021 ◽  
Author(s):  
Pei Zhang

<p>Grainflow, a fundamental agent moving sediment from the crest to the base of dune surfaces, leaves a temporary geomorphological signature on the slipfaces of aeolian dunes. The grainflow signature reflects the complex morphodynamical interaction between wind-driven sand transport and gravity-driven grainflow on an inclined surface. The purpose of this study is to present a method to objectively and efficiently delineate grainflow boundaries and characterize their morphology features by processing Digital Elevation Models (DEMs) obtained by terrestrial laser scanner in Matlab and ArcGIS. The method allows large numbers of grainflows to be quickly and objectively delineated and extracted from LiDAR data. As an aid tp subsequent analysis, the process avoids the subjective nature of manual measurement, thereby improving the commensurability of different grainflow regimes in both terrestrial and extraterrestrial environments. The results can be compared with the available grainflows morphology characteristics which are manually measured. The method is presented here in the context of analyzing grainflows and related processes on the slipfaces of dunes, but it is applicable over the broader scope of other forms of slope failure and geophysical flows, such as avalanches, snowslides, landslides, and debris flows.</p>


2018 ◽  
Vol 10 (2) ◽  
pp. 243-248
Author(s):  
Lei Lu ◽  
Chunxue Liu ◽  
Gang Chen ◽  
Liang Guo

Abstract Numerous geological research studies and mining operations have proved that fracture is one of the important factors controlling groundwater flow, mineralization, and ore distribution in metallic deposits. Most current approaches to groundwater flow simulation of naturally fractured media rely on the calculation of equivalent permeability tensors from a discrete fracture network (DFN). This study is aimed at developing a rational two-dimensional DFN by GEOFRAC, a geostatistical method of fracture direction and locations of sample data from a tin mine in the Gaosong area, Gejiu city, southwest China, and utilizing 3,724 outcrop fractures sampled on the ground of mountain Gaosong. Principal inputs of the DFN are density, direction, and continuity of disks that constitute a fracture plane. Fractures simulated by GEOFRAC were validated in that their directions corresponded well with those of the sample fractures. The permeability tensor of each modeling grid was then calculated based on the fracture network constructed. The results showed that GEOFRAC is valuable for two-dimensional DFN modeling in mines and other fracture-controlled geological phenomena, such as groundwater flow and slope failure.


2021 ◽  
Author(s):  
Tom Vincent Schintgen ◽  
Inga Sigrun Moeck

Abstract The Molasse Basin in Southern Germany is part of the North Alpine Foreland Basin and hosts the largest accumulation of deep geothermal production fields in Central Europe. Despite the vast development of geothermal energy utilization projects especially in the Munich metropolitan region, the evolution of and control factors on the natural geothermal field are still debated. Especially seismic and deep well data from extensive oil and gas exploration in the Molasse Basin led to conceptual hydrogeological and thermal-hydraulic models. Corrected borehole-temperature data helped to constrain subsurface temperatures by geostatistical interpolation and facilitated the set-up of 3D temperature models. However, within the geothermally used Upper Jurassic (Malm) carbonate aquifer, temperature anomalies such as the Wasserburg Trough anomaly to the east of Munich and their underlying physical processes are yet poorly understood. From other foreland basins like the Alberta Basin in Western Canada, it is known that climate during the last ice age has a considerable effect even on subsurface temperatures up to two kilometres depth. Therefore, we study the impact of paleoclimatic changes on the Molasse Basin during the last 130 ka including the Würm glaciation. We consider the hydraulic and thermal effects of periglacial conditions like permafrost formation and the impact of the numerous glacial advances onto the Molasse Basin. The major difference between the thermal-hydraulic regime in the western and eastern parts of the Southern German Molasse Basin are delineated by calculating two contrasting permeability scenarios of the heterogeneously karstified Malm carbonate aquifer. Thermal-hydraulic modelling reveals the effect of recurrent glacial periods on the geothermally drillable subsurface, which is minor compared to the effect of permeability-related, continuous gravity-driven groundwater flow as a major heat transport mechanism. Practically, the results might help to reduce the exploration risk for geothermal energy projects in the Molasse Basin. More importantly, this study serves as a reference for the comparison and understanding of the interplay of high permeability aquifers, gravity-driven groundwater flow and paleoclimate in other orogenic foreland basins worldwide.


2011 ◽  
Vol 6 (1) ◽  
pp. 80-87 ◽  
Author(s):  
Junko Nakaya ◽  
◽  
Kazunari Sako ◽  
Shunsuke Mitsutani ◽  
Ryoichi Fukagawa ◽  
...  

The hydrological environment must be understood before water flow can be adequately controlled to prevent slope failure without impacting unduly on the hydrological mountain slope environment. We conducted field studies to determine current sites and measurement of ground temperature 1 meter deep to clarify groundwater flow passageways on the slope behind the cultural heritage temple Kiyomizudera in Kyoto. Results showed anomalous temperature 1 meter deep bands on the slope and several springs that are extensions of these bands. Several of these bands coincide with terrain deformations such as gullies and slope failure scars indicating the probability of relationships between groundwater flow and topological deformation.


2006 ◽  
Vol 43 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Hiromu MORIWAKI ◽  
Shinobu YAZAKI ◽  
Wenfeng HUANG

Geography ◽  
2014 ◽  
Author(s):  
Simon M. Mudd

Much of the terrestrial surface of our planet is sloping. Rivers and glaciers occupy some of this terrain, but the vast majority of sloping grounds are hillslopes, or simply “slopes.” Slope processes are those that generate and transport soil or regolith. Both chemical and physical weathering occurs on and within slopes, and mass transport can be rapid and hazardous, as in the case of mass wasting, or gradual, as in the case of soil creep. Although humans have presumably pondered since prehistoric times why landscapes look the way they do, the formal study of slope processes has its roots in the 19th century, when scientists began debating how sediment is produced, the mechanisms and rates at which it is transported, and the manner in which sloping lands evolve through time. The field of slope processes continues today with the aim of predicting socially relevant phenomena such as slope failure and soil sustainability. Recent advances have been abetted by new techniques allowing unprecedented accuracy in characterizing the topography, chemistry, material properties, ages, and transport rates of sloping landscapes.


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