Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4714528 | Journal of Volcanology and Geothermal Research | 2006 | 12 Pages |
Abstract
We investigate the problem of estimating magma chamber geometry using InSAR observations of Sierra Negra Volcano, Galápagos. Ascending and descending interferograms are combined to determine vertical and one horizontal component of displacement. The ratio of maximum horizontal to vertical displacement suggests a sill-like source. Spherical or stock-like bodies are inconsistent with the data. We estimate the geometry of the sill assuming a horizontal, uniformly pressurized crack with unknown periphery and depth. The sill is discretized into small elements that are either open and are subjected to the pressure boundary condition or remain closed. We find the best-fitting sill to be located beneath Sierra Negra's inner caldera at a depth of about 2 km. Using boundary element calculations we show that any magma chamber with a flat top coincident with the sill model fits the data equally well. The data are insensitive to the sides and bottom of the magma chamber.
Keywords
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geochemistry and Petrology
Authors
S. Yun, P. Segall, H. Zebker,