Spatial analysis of stream power using GIS: SLk anomaly maps

Abstract

The stream length-gradient index (SL) shows the variation in stream power along river reaches. This index is very sensitive to changes in channel slope, thus allowing the evaluation of recent tectonic activity and/or rock resistance. Nevertheless, the comparison of SL values from rivers of different length is biased due to the manner in which the index is formulated, thus making correlations of SL anomalies along different rivers difficult. Therefore, when undertaking a comparison of SL values of rivers of different lengths, a normalization factor must be used. The graded river gradient (K ) has already been used in some studies to normalize the SL index. In this work, we explore the relationships between the graded river gradient (K), the SL index and the stream power, proposing the use of a re-named SLk index, which enables the comparison of variable-length rivers, as well as the drawing of SLk anomaly maps. We present here a GIS-based procedure to generate SLk maps and to identify SLk anomalies. In order to verify the advantages of this methodology, we compared an SLk map of the NE border of the Granada basin with both simple river profileknickpoint identification and with an SL map. The results show that the SLk map supplies good results with defined anomalies and suitably reflects the main tectonic and lithological features of the study area.

Active tectonics in the central and eastern Betic Cordillera through morphotectonic analysis: the case of Sierra Nevada and Sierra Alhamilla

“…ler and Pinter, 2002;Pérez-Peña et al, 2009a).The SL index is very sensitive to changes in channel slope. These changes are mainly due to lithologic, tectonic, or climatic factors.…”

“…These authors also proposed a new GIS-based methodology to create SLk anomaly maps by using geostatistical kriging. This methodology has been used to evaluate the activity of tectonic structures (faults and folds) in some recent studies in the Betic Cordillera with good results (Pérez-Peña et al, 2009a;Pedrera et al, 2009;Giaconia et al, 2012).…”

“…3), there is a lack of Quaternary ages, making it difficult to evaluate the Quaternary activity of the active structures within the basin. Pérez-Peña et al (2009a) studied the SLk index in the NE border of the Granada basin, and they proposed that the NW-SE normal faults presented evidences of Quaternary activity (Figs. 3 and 4).…”

Tectonic geomorphology of the Kemalpaşa Basin and surrounding horsts, southwestern part of the Gediz Graben, Western Anatolia

“…The topography of a region affected by recent and/or active tectonic process, such as faulting, can be an important factor in controlling geomorphic processes during landscape evolution (Bishop, 2007;Cox, 1994;Peréz-Peña, Azor, Azañon, & Keller, 2010). In this sense, the present day tectonic activity can be evaluated using geomorphic parameters which have been widely used to recognise the indicators of landforms deformed or modified by active faults (Brookfield, 1998;Chen, Sung, & Cheng, 2003;Keller, 1986;Keller & Pinter, 2002;Keller, Seaver, Laduzinsky, Johnson, & Ku, 2000;Molin, Pazzaglia, & Dramis, 2004;Pedrera, Peréz-Peña, Galindo-Zaldivar, Azañon, & Azor, 2009;Peréz-Peña, Azañon, Azor, Delgado, & Gonzàlez-Lodeiro, 2009). Mountain fronts generated by normal faulting are characterised by many morphologic structures.…”

Matlab-Based Tool for Drainage Network Ordering by Horton and Hack Hierarchies

“…Although numerous authors developed software to facilitate fluvial extraction and indices calculation (Schwanghart and Kuhn 2010;Pérez-Peña et al 2009) attaining a suitable channel network to tackle the automatic calculation of indices is still a quite time consuming process as most software extracts independent channel stretches instead of a continuous channel from headwater to mouth. While an entire channel is required to tackle stream long profile analysis (Jiménez-Cantizano et al 2017) and most of geomorphic indices.…”