Drainage diversions as evidence of propagating active faults: example of the El Asnam and Thenia faults, Algeria

Abstract

Digital elevation models and aerial photographs provide evidence of past drainage diversions associated with known and inferred active faults in Northern Algeria. The El Asnam anticline is a fault‐bend fold that is growing in response to displacement on the historically active El Asnam fault. The diversion of the Fodda River and a sequence of uplifted palaeovalleys across the anticline formed in response to the active southwestward propagation of the Sidi Ada–El Ardja segment of the El Asnam anticline. Deformation associated with the 1980 El Asnam earthquake (Ms 7.3) and its effect on drainage demonstrate the occurrence of coseismic uplift of the El Asnam anticline associated with slip on the underlying thrust fault. Similar geomorphic relations are observed between the Isser River and the Thenia fault. Diversions of the Isser River and evidence for Quaternary uplift indicate that the Thenia fault, which is close to Algiers, is tectonically active and should be considered to be a source of potentially damaging earthquakes.

Off-fault tip splay networks: A genetic and generic property of faults indicative of their long-term propagation

“…L f is the parent fault's length. (a) Altyn Tagh strike-slip fault (Meyer et al, 1998;Tapponnier et al, 2001); (b) VelinoMagnola normal fault (Schlagenhauf et al, 2011); (c) two stages of growth of an experimental strike-slip fault (Otsuki and Dilov, 2005); (d) Cheliff reverse fault (Boudiaf et al, 1998;Yielding et al, 1989).…”

Morphological response to Quaternary deformation at an intermontane basin piedmont, the northern Tien Shan, Kyrghyzstan

“…With such a small sourcing area the creeks seem underfit, indicating insufficient stream power to have entrenched the water gaps across the rising Ak-Teke Hills. Similar underfit conditions are often displayed by streams with extremely small drainage basins which appear to have accomplished a disproportionally great labor (Boudiaf et al, 1998;Hsieh and Knuepfer, 2001).…”

Strike–slip faulting, topographic growth and block movements as deduced from drainage anomalies: The Yeşilırmak River basin, northern Turkey

“…This second type of lateral channel movement is also termed deflection by others (McCalpin et al, 2009). Generally, the structural products of compressive tectonic regimes (i.e., anticlines, synclines, and reverse/thrust faulting) are responsible for such deflections/diversions (e.g., Boudiaf et al, 1998;Keller et al, 1999;Delcaillau, 2001;Burrato et al, 2003;Delcaillau et al, 2006;Lesh and Ridgway, 2007;Melosh and Keller, 2013).…”