The 2004 andesitic block-lava extrusion at Volcán de Colima, México was accompanied and
followed by numerous seismic signals associated with rockfalls, pyroclastic flows and
explosive events. We analyze temporal variations in the number of rockfalls and explosions,
the seismic signal duration of rockfalls and the energy of the explosion and compare this
with both the rate of magma discharge and SO2 emission. Characteristics of seismic signals
and SO2 emission are compared with those observed during the 1998–1999 Volcán de …