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Analysis of surface deformation data, Kilauea Volcano, Hawaii: October 1966 to September 1970

1983; American Geophysical Union; Volume: 88; Issue: B11 Linguagem: Inglês

10.1029/jb088ib11p09295

2156-2202

John J. Dvorak, Arnold T. Okamura, James H. Dieterich,

Geophysics and Gravity Measurements

A least squares inversion technique has been applied to surface displacement measurements made at Kilauea Volcano, Hawaii, in an attempt to locate centers of intrusive activity. Utilizing analytic expressions for the displacement field arising from dilatational sources in an elastic half space, this technique allows for the simultaneous inversion of level, tilt, and horizontal distance measurements in terms of the location and volume of the intrusive body. A variety of simple elastic model geometries, representing possible shapes for intrusive bodies in the summit region of Kilauea, were examined. None of the model geometries considered significantly improved the quality of the model fit to the available data over that obtained by a point source model. Calculations based on elastic models to consecutive level surveys were compared to available tilt data and horizontal distance measurements. These comparisons indicate occasional departures from ideal elastic behavior. The departure of measured tilt patterns from calculated tilt values may be the result of earthquake activity or episodic block movements superimposed on larger elastic displacements. The departure of measured and calculated horizontal measurements reveals a gradual north‐south extensional strain across the summit caldera of Kilauea in addition to the elastic uplift and subsidence patterns determined from level surveys. A minimum estimate for the magma supply rate to Kilauea is provided by the elastic models to the level data. The average rate for the period from October 1966 to September 1970 was 0.07 km 3 per year.