Origin of the northeastern basin and range seismic parabola: Thermal and mechanical effects of the Yellowstone hotspot

Conference · Thu Apr 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5419726

Anders, M H ^[1]

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1. Columbia Univ., Palisades, NY (United States). Lamont-Doherty Earth Observatory and Dept. of Geological Sciences

Centered about the track of the Yellowstone hotspot is a parabolic pattern of seismicity encompassing a region of aseismicity. Recent studies have shown that this pattern has migrated in tandem with the hotspot. A one dimensional finite-difference thermomechanical model is developed which successfully accounts for the observed patterns of seismicity. The volume, chemistry and timing of magma intrusion used in the model are contained by several geophysical, geochemical and geochronological studies of the eastern Snake River Plain. In this model, mafic magmas are intruded into a lithosphere that is already extending. The intrusions heat the surrounding rock resulting in locally increased strain rates. As the intruded magmas solidify, the length of time required to return strain rates to their pre-intrusion level is then determined. The model assumes constant horizontal tectonic forces and maps strain rate as a function of yield strength and time since intrusion. Model parameters such as crustal thickness, initial geothermal gradient, and amount of magma intruded, are varied in order to assess how they affect turnaround time for strain rates. Off-axis seismicity (seismicity within the seismic parabola exclusive of Yellowstone) is accounted for by lower crustal flow. The lower crustal flow under the seismic parabola is driven by buoyancy forces generated by a sublithospheric plume. The shape of the seismic parabola is controlled by the combination of two irrotational fields; a radial flow field due to the plume and a constant velocity field corresponding to plate motion. In summation the author discusses several other models that have recently been proposed to explain the observed patterns of seismicity and late Cenozoic tectonism of the northeastern Basin and Range province.

• OSTI ID: 5419726
• Report Number(s): CONF-9305259--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:5
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150200 -- Geology & Hydrology of Geothermal Systems
58 GEOSCIENCES
580000* -- Geosciences
CALCULATION METHODS
DEVELOPED COUNTRIES
FINITE DIFFERENCE METHOD
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGY
GEOTHERMAL GRADIENTS
GEOTHERMAL SYSTEMS
IDAHO
ITERATIVE METHODS
MAGMA SYSTEMS
MAGMATISM
MATHEMATICAL MODELS
NEVADA
NORTH AMERICA
NUMERICAL SOLUTION
OREGON
PUBLIC LANDS
SEISMICITY
SNAKE RIVER PLAIN
STRAINS
TEMPERATURE GRADIENTS
USA
WYOMING
YELLOWSTONE NATIONAL PARK