Surface deformation associated with volcanism

Changes in pressure of magma or intrusion into new passages causes the surface of the earth to deform. Vertical and horizontal displacements measured at Kilauea volcano in Hawaii are characteristic of those produced by a change in pressure of magma in a vertical column extending upward from depth to a point about 1.5 km below the center of uplift. Theoretical solutions for a line source of dilatation in a half-space show that surface displacements are not sensitive to small changes in the angle of dip. Also, several radially symmetric sources produce similar surface deformation fields, and so careful measurement of the complete field is necessary in order to make reliable estimates of the configuration of the source.