Green-tree retention is being implemented on state and
federal lands in Oregon. Silvicultural prescriptions with
tree and snag retention are thought to mimic natural
disturbance patterns in the Pacific Northwest more closely
than traditional silvicultural practices, which reduce
structural complexity. The effects of green-tree retention
on native bird species in...
In eastern Washington and western Oregon, southwest-northeast striking thrust faults and folds of the Yakima Fold and Thrust Belt (YFTB) and northwest-striking dextral strike-slip faults accommodate north-south contraction resulting from clockwise rotation of the North American Plate. Though present to the east and west of the Cascade Range, the connectivity...
Floodplain forests play many important roles in the fluvial processes and environments of large alluvial rivers, including acting as geomorphological influences and habitat for native fish during high flows. Many large, gravel-bed river systems have undergone substantial change in recent centuries, resulting in loss of forested area to agriculture, reduction...
The word orogenesis is derived from the Greek words oros meaning mountains and genesis meaning creation and refers to the study of the complex processes involved in the growth and evolution of mountain ranges (orogens). Orogens develop where crustal deformation builds topography and forms landscapes. This dissertation explores the role...
Hydrogeologic systems in the southern Cascade Range develop in volcanic rocks where volcanic morphology, stratigraphy, extensional structures and attendant basin geometry play a central role in groundwater-flow paths, groundwater/surface-water interactions, and spring discharge locations. High-volume springs (> 3 m3/s) flow from young (< 1 Ma) volcanic rocks in the Hat...
Discrete fault systems accommodate both N-S contraction and dextral shear in concert with clockwise rotational deformation of the North American plate above the Cascadia Subduction Zone. In Washington, the Yakima Fold and Thrust Belt (YFTB) accommodates N-S contraction as a series of ENE-WSW trending thrust faults and folds. NW-striking, predominantly...
Advancing the understanding of natural resource management is an important step in mitigating the effects of human activity on the environment, and ensuring efficient outcomes for many sectors of the economy. As humanity’s role in the natural world becomes better understood, the importance of interdisciplinary modeling has grown in leaps...
Cascadia’s 1700 earthquake generated a tsunami and widespread subsidence along Pacific Northwest coastline. The tsunami deposited sandy sediments in many Oregon coastal estuaries, such as Alsea Bay. Although the recurrence of subduction-generated megathrust earthquakes and tsunami events in this region are recorded in the stratigraphy, knowledge of the full inland...
Earthquake rupture scenarios are important tools for understanding the nature of plate movement and patterns in seismic activity. The creation and assessment of these rupture scenarios rely heavily on geologic reasoning and principles applied to earthquake event data. This reliance introduces a certain amount of subjectivity to the rupture scenario...
Active tectonics of a deformation front constrains the kinematic evolution and structural interaction between the fold-thrust belt and the most-recently accreted foreland basin. At the Himalayan deformation front, the thrust front is blind, characterized by a broad fold (the Suruin-Mastgarh anticline (SMA)), and displays no emergent faults cutting the southern...
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AndrewJ. Meigs
ABSTRACT
Active tectonics of a deformation front constrains the
