Deformation from 1973 to 1987 in the epicentral area of the 1959 Hebgen Lake, Montana, earthquake (Ms = 7.5)

Journal of Geophysical Research B: Solid Earth
By: , and 

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Abstract

A 40‐km aperture trilateration network centered on the 1959 Hebgen Lake earthquake epicenter has been surveyed in 1973, 1974, 1976, 1978, 1981, 1984, and 1987. The deformation inferred from those surveys is described roughly by a uniaxial, 0.266 ± 0.014 μstrain/yr, N15°E ± 1°extension that is uniform in both time and space. That extension is orthogonal to the strike (N78°W ± 5°) of the 1959 rupture plane inferred from focal mechanism solutions. The absence of strain accumulation in the N75°W direction suggests that the source of deformation must be greatly elongated in that direction. Looked at in greater detail, the deformation is found to be concentrated in the northern part of the network. The zone of concentrated deformation coincides with a part of a well‐defined trend in seismicity that extends at least 100 km N75°W from the Sour Creek resurgent dome in the Yellowstone caldera. Extension perpendicular to that trend is indicated by focal mechanism solutions. Thus, the zone of rifting identified within the Hebgen Lake network apparently extends east southeast to the Yellowstone caldera. About 8 mm/yr extension is observed across a 20‐km width within the zone.

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Publication type Article
Publication Subtype Journal Article
Title Deformation from 1973 to 1987 in the epicentral area of the 1959 Hebgen Lake, Montana, earthquake (Ms = 7.5)
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1029/92JB02410
Volume 98
Issue B2
Year Published 1993
Language English
Publisher American Geophysical Union
Contributing office(s) Earthquake Science Center, Volcano Hazards Program
Description 9 p.
First page 2145
Last page 2153
Country United States
State Montana, Wyoming
Other Geospatial Yellowstone-Hebgen Lake Region
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