Browsing by Author "Aron, Felipe"

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    Bridging earthquakes and mountain building in the Santa Cruz Mountains, CA
    (2022) Baden, Curtis W.; Shuster, David L.; Aron, Felipe; Fosdick, Julie C.; Burgmann, Roland; Hilley, George E.
    Relative crustal motions along active faults generate earthquakes, and repeated earthquake cycles build mountain ranges over millions of years. However, the long-term summation of elastic, earthquake-related deformation cannot produce the deformation recorded within the rock record. Here, we provide an explanation for this discrepancy by showing that increases in strain facilitated by plastic deformation of Earth's crust during the earthquake cycle, in conjunction with isostatic deflection and erosion, transform relative fault motions that produce individual earthquakes to geologic deformations. We focus our study on the data-rich Santa Cruz Mountains, CA, USA and compare predicted and observed quantities for rock uplift, apatite (U-Th)/He thermochronology, topographic relief, Be-10-based erosion rates, and interseismic surface velocities. This approach reconciles these disparate records of mountain-building processes, allowing us to explicitly bridge decadal measures of deformation with that produced by millions of years of plate motion.
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    Climate aridity delays morphological response of Andean river valleys to tectonic uplift
    (2023) Harries, Rebekah M.; Aron, Felipe; Kirstein, Linda A.
    In the south Central Andes, a complex relationship between climate, tectonics, erosion and topography is well documented. Building on recent advances in the mechanical modelling of subduction zones, we isolate the contribution of fault motion to topography and observe how rock uplift has been recorded in river valley morphology. Rivers on the wetter, western Chilean-side of the Andean cordillera have steep and narrow valleys, in stark contrast to those draining east across the arid Argentinian cordillera, whose valleys are variably wider and less steep. The Chilean rivers have responded to fault slip along the western mountain front by incising vertically and propagating a steepening zone upstream. In Argentina, there is little evidence of channel steepening despite predictions for higher vertical rock uplift rates. We hypothesise that the aridity of the Argentinian region has limited the transport capacity of the rivers to export their sediment fill and as a result, vertical incision has been inhibited and lateral incision and valley widening favoured. The long-term climate gradient appears to have been important in modulating the morphological response of these rivers to fault slip. These factors precondition future landscape sensitivity to both tectonic and climatic change.
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    Constructing forearc architecture over megathrust seismic cycles : Geological snapshots from the Maule earthquake region, Chile
    (2015) Aron, Felipe; Cembrano, José; Astudillo, Felipe; Allmendinger, Richard W.; Arancibia Hernández, Gloria Cecilia
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    Mountain Rivers Reveal the Earthquake Hazard of Geologic Faults in Silicon Valley
    (2022) Aron, Felipe; Johnstone, Samuel A.; Mavrommatis, Andreas; Sare, Robert; Maerten, Frantz; Loveless, John P.; Baden, Curtis W.; Hilley, George E.
    The 1989, M-w = 6.9 Loma Prieta earthquake resulted in tens of lives lost and cost California almost 3% of its gross domestic product. Despite widespread damage, the earthquake did not clearly rupture the surface, challenging the identification and characterization of these hidden hazards. Here, we show that they can be illuminated by inverting fluvial topography for slip-and moment accrual-rates-fundamental components in earthquake hazard assessments-along relief-generating geologic faults. We applied this technique to thrust faults bounding the mountains along the western side of Silicon Valley in the San Francisco Bay Area, and discovered that these structures may be capable of generating a M-w = 6.9 earthquake every 250-300 years based on moment accrual rates. This method may be deployed broadly to evaluate seismic hazard in developing regions with limited geological and geophysical information.
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    Permanent fore-arc extension and seismic segmentation : Insights from the 2010 Maule earthquake, Chile
    (2013) Aron, Felipe; Allmendinger, Richard W.; Cembrano, José; González, Gabriel; Yáñez Carrizo, Gonzalo Alejandro