Fault Throw and Regional Uplift Histories from Drainage Analysis: Evolution of Southern Italy

Abstract

The evolution of normal faults has important implications for long-term seismic hazard, and changes in topography during the development of a fault array impact upon a range of factors including plate rheology and sediment routing (e.g., Cowie et al., 2017;Li et al., 2016;Marc et al., 2016). Techniques such as trenching and cosmogenic dating of fault scarps can constrain fault throw rates over time scales of ∼10 2 -10 3 years and can successfully estimate earthquake recurrence intervals (e.g., Cowie et al., 2017;Pantosti et al., 1993;Roberts & Michetti, 2004). Fault throw over longer time scales (>10 3 years) can be investigated using stratigraphic data and structural cross sections (e.g., Ford et al., 2013;Mirabella et al., 2011;Shen et al., 2017); however, a complete temporal and spatial record of throw rates may be limited by the absence of datable stratigraphy.Fortunately, fluvial networks provide an opportunity to overcome these limitations and constrain throw rate on the length and time scales that may be pertinent to the development of a fault array, i.e., ∼10 2 -10 5 m and ∼10 4 -10 7 years (e.g., Cowie et al., 2000;McLeod et al., 2000). Quantitative fluvial erosion models can elucidate tectonic changes without necessarily relying upon the stratigraphic archive, signifying their importance in low-mid latitude terrestrial settings where fluvial landscapes are ubiquitous. The morphology and erosion rates of individual rivers have been used to confirm the location of active faults, estimate increases in throw rate, and understand fault interaction or relay ramp development (e.g., Commins et al., 2005;Hopkins & Dawers, 2015). These studies have successfully shown that drainage morphology is sensitive to the evolution of individual fault strands. Nonetheless, active faulting rarely occurs in isolation from other tectonic processes (e.g., mantle flow, plate flexure, isostatic rebound), which often modify topography over larger spatial scales (e.g., 10 5 m). Therefore, separating the effect of faulting from the other factors that generate topography remains a wider challenge in tectonic and geomorphic research.