Ma. Hofton et al., HORIZONTAL SURFACE DEFORMATION DUE TO DIKE EMPLACEMENT IN AN ELASTIC-GRAVITATIONAL LAYER OVERLYING A VISCOELASTIC-GRAVITATIONAL HALF-SPACE, J GEO R-SOL, 100(B4), 1995, pp. 6329-6338
We extend a technique previously used to model surface displacements r
esulting from thrust faulting in an elastic-gravitational layer over a
viscoelastic-gravitational half-space to the case of dike emplacement
. The method involves the calculation of the Green's functions for a d
ike point source contained in an elastic-gravitational layer over an e
lastic-gravitational half-space. The correspondence principle is then
applied to introduce time dependence. The resultant Green's functions
are integrated over the source region to obtain the near-field displac
ements. Several example calculations are presented involving 90 degree
s, 60 degrees, and 30 degrees dipping dikes, extending completely and
partially through the elastic layer. We also illustrate the time depen
dent deformation due to buried dikes. Dikes extending completely throu
gh the elastic layer produce a larger-amplitude long-wavelength compon
ent than those extending partially through the elastic layer. Inflexio
n points are seen in the dike-normal horizontal deformation profiles w
hen the base of the dike intersects the top of the half-space, providi
ng a means of differentiating between vertical surface dikes extending
completely and partially through the elastic layer. All results show
that the use of a viscoelastic half-space underlying an elastic layer
introduces a long-wavelength component into the deformation field that
cannot be predicted by elastic half-space models.