Preprints
Filtering by Subject: Geomorphology
Cave airflow patterns control calcite dissolution rates within a cave stream: Blowing Springs Cave, Arkansas, USA
Published: 2020-05-24
Subjects: Earth Sciences, Environmental Sciences, Geochemistry, Geomorphology, Hydrology, Physical Sciences and Mathematics
Erosion rates within streams vary dramatically over time, as differences in discharge and sediment load enhance or inhibit erosion processes. Within cave streams, and other bedrock channels incising soluble rocks, changes in water chemistry are an important factor in determining how erosion rates will vary in both time and space. Prior studies within surface streams, springs, and caves suggest [...]
The perpetual fragility of creeping hillslopes
Published: 2020-05-18
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Soil-mantled hillslopes owe their smooth, convex shape to creep; the slow and persistent, gravity-driven motion of grains on slopes below the angle of repose. Existing models presume that soil creep occurs via mechanical displacement of grains by (bio)physical disturbances. Recent simulations, however, suggest that soil can creep without these disturbances, due to internal relaxation dynamics [...]
Macroscopic flow disequilibrium over aeolian dune fields
Published: 2020-05-08
Subjects: Atmospheric Sciences, Earth Sciences, Geomorphology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology
Aeolian dune fields are self-organized patterns formed by wind-blown sand. Dunes are topographic roughness elements that impose drag on the atmospheric boundary layer (ABL), creating a natural coupling between form and flow. While the steady-state influence of drag on the ABL is well studied, non-equilibrium effects due to roughness transitions are less understood. Here we examine the large-scale [...]
Projections of global delta land loss from sea-level rise in the 21st century
Published: 2020-05-06
Subjects: Earth Sciences, Geomorphology, Hydrology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology
River deltas will likely experience significant land loss because of relative sea-level rise (RSLR), but predictions have not been tested against observations. Here, we use global data of RSLR and river sediment supply to build a model of delta response to RSLR for 6,402 deltas, representing 86% of global delta land. We validate this model against delta land area change observations from [...]
Rock glaciers represent hidden water stores in the Himalaya
Published: 2020-05-06
Subjects: Earth Sciences, Geomorphology, Glaciology, Hydrology, Physical Sciences and Mathematics
In High Mountain Asia (HMA), ongoing glacier retreat affects human and ecological systems through reduced water availability. Rock glaciers are climatically more resilient than glaciers and likely contain potentially valuable water volume equivalents (WVEQ). In HMA knowledge of rock glaciers is extremely sparse and here we present the first systematic assessment of rock glaciers for the Himalaya, [...]
Modeling the spatial dynamics of marsh ponds in New England salt marshes
Published: 2020-04-27
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Ponds are common features on salt marshes, yet it is unclear how they affect large-scale marsh evolution. We developed a spatially explicit model that combines cellular automata for pond formation, expansion, and drainage, and partial differential equations for elevation dynamics. We use the mesotidal Barnstable marsh (MA, USA) as a case study, for which we measured pond expansion rate by remote [...]
Runout of rock avalanches limited by basal friction but controlled by fragmentation
Published: 2020-04-22
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Rock avalanches display exceptionally long runouts, which are found to correlate with their volume and attributed to size dependent dynamic lowering of the effective basal friction. However, even for similar volumes, runouts are seen to span several orders of magnitude suggesting additional controlling factors. Here, we document experiments with analogue models of rock avalanches aimed at testing [...]
A seismic monitoring approach to detect and quantify river sediment mobilisation by steelhead redd-building activity
Published: 2020-04-20
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
The role of spawning salmonids in altering river bed morphology and sediment transport is significant yet poorly understood. This is due, in large part, to limitations in monitoring the redd-building process in a continuous and spatially extended way. A complementary approach may be provided through the use of a small seismic sensor network analysing the ground motion signals generated by the [...]
Lateral variability in strain along a mass-transport deposit (MTD) toewall: a case study from the Makassar Strait, offshore Indonesia
Published: 2020-04-18
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology
Contractional features characterise the toe domain of mass-transport deposits (MTDs). Their frontal geometry is typically classified as frontally-confined or frontally-emergent. However, it remains unclear how frontal emplacement style and contractional strain within an MTD can vary along strike. We use bathymetry and 3D seismic reflection data to investigate lateral variability of frontal [...]
Lateral variations in lower crustal strength control the temporal evolution of mountain ranges: examples from south-east Tibet
Published: 2020-04-17
Subjects: Earth Sciences, Geochemistry, Geomorphology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Controversy surrounds the rheology of the continental lithosphere, and how it controls the evolution and behaviour of mountain ranges. In this study, we investigate the effect of lateral contrasts in the strength of the lower crust, such as those between cratonic continental interiors and weaker rocks in the adjacent deforming regions, on the evolution of topography. We combine numerical [...]
InSAR Time Series Analysis of L-band Wide- Swath SAR Data Acquired by ALOS-2
Published: 2020-04-12
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Operating at L-band (~24 cm wavelength) in wide-swath modes is one of the characteristics of the new and next generation satellite synthetic aperture radar (SAR) missions. After 3 years of operation, the Japan Aerospace Exploration Agency Advanced Land Observing Satellite-2 (ALOS-2) satellite has acquired a wealth of L-band wide-swath SAR data over many areas using its ScanSAR mode. We present [...]
Turbidites, Topography and Tectonics: Evolution of submarine channel-lobe systems in the salt-influenced Kwanza Basin, offshore Angola
Published: 2020-04-07
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology
Understanding the evolution of submarine channel-lobe systems on salt-influenced slopes is challenging as systems react to seemingly subtle changes in sea-floor topography. The impact of large blocking structures on individual deep-water systems is well documented, but understanding of the spatio-temporal evolution of regionally extensive channel-lobe systems in areas containing modest salt [...]
Measuring Azimuth Deformation With L-Band ALOS-2 ScanSAR Interferometry
Published: 2020-04-06
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Computational Engineering, Computer Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Signal Processing, Tectonics and Structure, Volcanology
We analyze the methods for measuring azimuth deformation with the L-band Advanced Land Observing Satellite-2 (ALOS-2) scanning synthetic aperture radar (ScanSAR) interferometry. To implement the methods, we extract focused bursts from the ALOS-2 full-aperture product, which is the only product available for ScanSAR interferometry at present. The extracted bursts are properly processed to measure [...]
Estimating Azimuth Offset With Double-Difference Interferometric Phase: The Effect of Azimuth FM Rate Error in Focusing
Published: 2020-04-06
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Tectonics and Structure, Volcanology
Estimating azimuth offset with double-difference interferometric (DDI) phase, which is called multiple-aperture interferometric synthetic aperture radar (InSAR) or spectral diversity, is increasingly used in recent years to measure azimuth deformation or to accurately coregister a pair of InSAR images. We analyze the effect of frequency modulation (FM) rate error in focusing on the DDI phase with [...]
Climate controls the length and shape of the world’s drainage basins
Published: 2020-04-01
Subjects: Earth Sciences, Geomorphology, Hydrology, Physical Sciences and Mathematics
Submitted manuscript currently under review at Geophysical Research Letters (American Geophysical Union publication).