Daniel O'Hara

Daniel O'Hara
Vrije Universiteit Brussel | VUB · Department of Geography

Doctor of Philosophy

About

20
Publications
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93
Citations

Publications

Publications (20)
Article
Full-text available
Like many other lakes in the world, the interconnected Abaya and Chamo lakes in the Southern Main Ethiopian Rift are affected by rapid sediment accumulation. Although land degradation is a well-known issue in this part of the African continent, the main sediment sources, their spatial distribution and interaction in the Abaya–Chamo lakes’ basin hav...
Article
Full-text available
Like many other lakes in the world, the interconnected Abaya and Chamo lakes in the Southern Main Ethiopian Rift are affected by rapid sediment accumulation. Although land degradation is a well-known issue in this part of the African continent, the main sediment sources, their spatial distribution and interaction in the Abaya–Chamo lakes’ basin hav...
Presentation
The long-term (ka to ma) degradation of a volcanic edifice is controlled by both regional (e.g., climate, tectonics) and local factors (e.g., original morphology, lithology), resulting in both long-lasting weathering and river incision and short-term hazardous events, such as flank collapses and lahars. Trends among the morphometry of stratovolcano...
Conference Paper
Volcano morphology is the result of complex interactions between constructive and destructive phases. The dynamics of eruptive, intrusive and erosive processes are reflected in the shapes of volcanoes today. Quantifying the morphology and degradation patterns of composite volcanoes can provide new insights into the evolution of these landforms and...
Article
Transcrustal magma transport systems reflect accumulation of small-volume intrusions over long timescales, transiently altering the thermal, mechanical, and compositional states of the crust. The long-term impact of such repeated and spatially-distributed intrusive magmatism on surface topography remains relatively unexplored. Here, we investigate...
Conference Paper
Full-text available
Volcanoes are extremely dynamic landforms. They grow by the accumulation of eruptive products and intrusions and degrade by a range of erosion processes such as superficial runoff, chemical and physical weathering, fluvial and glacial incision, and mass movements. In this study, we aim at documenting and quantifying the morphology of natural compos...
Article
Full-text available
Plain Language Summary Magma reservoirs are commonly assumed to be located directly beneath their associated volcanic edifices. This “central reservoir” paradigm dominates volcano modeling and monitoring. However, the actual spatial relations between volcanoes and underlying magma reservoirs are poorly known. We compile a database of geophysical st...
Article
Full-text available
Increased resolution of data constraining topography and crustal structures provides new quantitative ways to assess province-scale surface-subsurface connections beneath volcanoes. We used a database of mapped vents to extract edifices with known epoch ages from digital elevation models (DEMs) in the Cascades arc (western North America), deriving...
Article
A primary goal of geomorphology is to infer from topographic form the processes that drive landscape evolution. Often implicit is the assumption that orogen-scale ( m^2 planform area) transient landscape changes on Earth are driven by equally large-scale transient tectonics, climate, or sea level. Here we argue that meso-scale (10^5–10^10 m^2) upli...
Conference Paper
Full-text available
Topography of the Cascades Arc encodes a complex history of volcanism, tectonics, and erosion. Edifices range from cinder cones to calderas, stratovolcanoes, and compound volcanic complexes. Often, these features are spatially localized around magmatic centers, alluding to the underlying magma transport network. A new USGS database compiles the loc...
Article
Magmatism is an important driver of landscape adjustment over ∼10% of Earth's land surface, producing 10³- to 10⁶-km² terrains that often persistently resurface with magma for 1–10 s of Myr. Construction of topography by magmatic intrusions and eruptions approaches or exceeds tectonic uplift rates in these settings, defining regimes of landscape ev...
Article
In subduction zone backarcs extensional deformation and arc volcanism interact and these processes, together with mass wasting, shape the seafloor morphology. We present a new bathymetric map of the Santorini-Christiana-Amorgos backarc region of the Hellenic subduction zone by merging high-resolution multibeam swath data from the R/V Langseth PROTE...
Article
Tectonic slivers have profound implications on the mechanical behavior of forearcs and subduction zones. Southern Taiwan is characterized by pre-collision forearc slivering that likely exerts important controls on the evolution of collision. Inversion of focal mechanism solutions for seismogenic strain reveals spatially partitioned plate motion sou...
Conference Paper
Full-text available
Taiwan is the product of modern subduction polarity reversal coupled with arc-continent collision. The NW-moving Philippine Sea plate (PSP) subducts beneath the Eurasian plate (EUR) to the northeast of Taiwan at the Ryukyu trench, while overriding EUR south of Taiwan at the Manila trench, bringing the Luzon volcanic arc into collision with the defo...
Article
Earthquakes in the upper plate offshore SE Taiwan provide insight into the crustal assembly of the eastern Taiwan arc-continent collision. We invert groups of focal mechanisms for best-fitting strain tensors and show that eastern Taiwan likely records a pre-collision history of partitioned deformation overprinted by collision-driven plate-motion pa...
Article
Full-text available
Slip vectors of preferred nodal planes derived using a Gaussian model for inverting focal mechanisms for strain provide constraints on probable fault geometries and fault block kinematics. We use preferred nodal plane slip vectors for shallow earthquakes in the Luzon forearc basin of southeast Taiwan to understand the relative orientations of block...
Article
The Huatung Ridge is a north-trending bathymetric high situated between the Luzon Arc and the Southern Longitudinal Trough off the coast of SE Taiwan. Strain inversions for shallow (

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Projects

Project (1)
Project
Explore the relationship between volcanic topography and underlying crustal structure of the Cascades Arc (western U.S.). Completed by quantifying the volumes and spatial distributions of Quaternary volcanic edifices, and combining these with other Cascades datasets (heat flux, gravity, surface strain rates, and seismic velocities) to examine the relationship between volcanic vents and the crustal magmatic system.