This paper studies the effects of strain sources at depth, simulating volca
nic source activation, on the changes of Coulomb failure stress in the surr
ounding volume. Such simulations are aimed at clarifying the relationship b
etween volcano dynamics and seismicity generated by stress changes. The eff
ect of isotropic overpressure or dike opening on the Coulomb stress pattern
s is shown here, in presence of a background tectonic stress. Seismicity pa
tterns resulting from such stress changes can thus be used to shed light on
the sources involved. Simulations of Coulomb stress changes associated to
the opening of the Northeast rifts at Kilauea volcano (Hawaii) have been pe
rformed, showing that seismicity at this area is well explained by stress c
hanges produced by rift opening (i.e. without any contribution out of local
sources), both in terms of location patterns and focal mechanisms. In part
icular, the widely observed focusing of seismicity in the southern flank ca
n be explained in terms of Coulomb stress changes generated by rift opening
, once the different opposing masses in the northern and southern flank is
taken into account. In addition, Coulomb stress changes due to rift opening
are shown to explain both the occurrence of large earthquakes and of the s
eaward sliding of the Southern flank, on the low-angle reverse faults hypot
hesized at the base of the rift zone. (C) 2001 Elsevier Science B.V. All ri
ghts reserved.