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Publication . Article . Other literature type . 2017

Landscape response to progressive tectonic and climatic forcing in NW Borneo: Implications for geological and geomorphic controls on flood hazard

David Menier; Manoj Joseph Mathew; Manuel Pubellier; François Sapin; Bernard Delcaillau; Numair Ahmed Siddiqui; Mu. Ramkumar; +1 Authors
Open Access
Published: 01 Mar 2017 Journal: Scientific Reports (issn: 2045-2322, Copyright policy )
Publisher: Nature Publishing Group UK
Country: France

(IF 4.12; Q1); International audience; Empirical models have simulated the consequences of uplift and orographic-precipitation on the evolution of orogens whereas the effects of these forcings on ridgelines and consequent topography of natural landscapes remain equivocal. Here we demonstrate the feedback of a terrestrial landscape in NW Borneo subject to uplift and precipitation gradient owing to orographic effect, and leading to less-predictable flooding and irreversible damages to life and property. Disequilibrium in a large catchment recording the lowest rainfall rates in Borneo, and adjacent drainage basins as determined through χ, a proxy for steady–state channel elevation, is shown to result in dynamic migration of water divide from the windward-side of the orogen towards the leeward-side to attain equilibrium. Loss of drainage area in the leeward-side reduces erosion rates with progressive shortening resulting in an unstable landscape with tectonic uplift, gravity faults and debris flows. 14 C dating of exhumed cut-and-fill terraces reveal a Mid–Pleistocene age, suggesting tectonic events in the trend of exhumation rates (>7 mm a −1) estimated by thermochronology, and confirmed by morphotectonic and sedimentological analyses. Our study suggests that divide migration leads to lowered erosion rates, channel narrowing, and sediment accretion in intermontane basins on the leeward-side ultimately resulting in enhanced flooding. The continued, yet variable rates of interactions between tectonic and climatic forcing result in diversity of landscape evolution. A number of physical and numerical models 1–4 have shown the effects of uplift and orographi-cally enhanced precipitation on the evolution of active mountain ranges. However, in a natural landscape, subject to tectonic uplift and climatic perturbations, the feedback of ridgelines and subsequent rain-shadowed topography remains less-understood. These natural processes, often aggravated by anthropogenic intervention can result in catastrophic geohazards such as flooding, causing irreversible damages. The consequences of floods include loss of human life, crops and livestock, and the spread of water borne diseases 5–7. Economic vulnerability arising from damage to infrastructure such as roads and bridges could have long–term impacts causing disruption to transportation and emergency flood evacuation services. Thus, understanding the consequences of varied landscape evolution under the influences of tectonic and climatic forcing has critical inputs for mitigation of geohazards especially in tectonically dynamic, climatically sensitive and highly populated regions of the World such as Southeast Asia. NW Borneo (Fig. 1) is a typical example where floods have caused community disruption

Subjects by Vocabulary

Microsoft Academic Graph classification: Disequilibrium medicine.symptom medicine Precipitation Tectonics Orographic lift Debris Geomorphology Thermochronology Geology Drainage basin geography.geographical_feature_category geography Tectonic uplift


[SDU]Sciences of the Universe [physics], Article, Medicine, R, Science, Q, Multidisciplinary