Imperial College London
Portrait Picture

Dr Alex Whittaker

Faculty of Engineering, Department of Earth Science & Engineering

Reader in Landscape Dynamics
 
 
 
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Contact

 

+44 (0)20 7594 7491a.whittaker Website

 
 
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Location

 

3.51Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Quye-Sawyer:2020:10.1016/j.geomorph.2020.107388,
author = {Quye-Sawyer, J and Whittaker, AC and Roberts, GG},
doi = {10.1016/j.geomorph.2020.107388},
journal = {Geomorphology},
pages = {1--14},
title = {Calibrating fluvial erosion laws and quantifying river response to faulting in Sardinia, Italy},
url = {http://dx.doi.org/10.1016/j.geomorph.2020.107388},
volume = {370},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - It is now widely accepted that rivers modify their erosion rates in response to variable rock uplift rates, resulting in changes in channel slope that propagate upstream through time. Therefore, present-day river morphology may contain a record of tectonic history. The simple stream power incision model can, in principle, be used to quantify past uplift rates over a variety of spatial and temporal scales. Nonetheless, the erosional model's exponents of area and slope (m and n respectively) and ‘bedrock erodibility’ (k) remain poorly constrained. In this paper, we will use a geologically and geomorphically well constrained Plio-Pleistocene volcanic landscape in central Sardinia, Italy, to calibrate the stream power erosion equation and to investigate the slip rate of faults that have been seismically quiescent in the historic past. By analysing digital elevation models, geological maps and Landsat imagery, we have identified the geomorphic expression of several volcanic features (eruption centres and basaltic lava flows) and three normal faults with 6 to 8km fault traces within the outcrop. Downstream, river longitudinal profiles show a similar transient response to relative base level fall, probably as a result of relief inversion at the edge of the volcanic outcrop. From measurements of incision, local slope and upstream catchment area across eight different rivers, we calculate n ≈ 1, m = 0.50 ± 0.02 and, using a landscape age from literature of 2.7Ma, bedrock erodibility k = 0.10 ± 0.04m(1−2m) Myr−1. There are also knickpoints on rivers upstream of two normal faults, and we used numerical inverse modelling of the longitudinal profiles to predict the slip rate of these faults since 2.7Ma. The results from the inverse model show that the erosional parameter values derived in this study can produce theoretical longitudinal profiles that closely resemble observed river profiles upstream of the faults. The lowest misfit
AU  - Quye-Sawyer,J
AU  - Whittaker,AC
AU  - Roberts,GG
DO  - 10.1016/j.geomorph.2020.107388
EP  - 14
PY  - 2020///
SN  - 0169-555X
SP  - 1
TI  - Calibrating fluvial erosion laws and quantifying river response to faulting in Sardinia, Italy
T2  - Geomorphology
UR  - http://dx.doi.org/10.1016/j.geomorph.2020.107388
UR  - https://www.sciencedirect.com/science/article/pii/S0169555X20303615?via%3Dihub
UR  - http://hdl.handle.net/10044/1/81938
VL  - 370
ER  -
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