From November 1995 to December 1997 a total volume of 246¿106 (DRE) m3 of andesite magma erupted, partitioned into 93¿106 m3 of the dome, 125¿106 m3 of pyroelastic flow deposits and 28¿106 m3 of explosive ejecta. In the first 11 weeks magma discharge rate was low (0.5 m3/s). From February 1996 to May 1997 discharge rates have averaged 2.1 m3/s, but have fluctuated significantly and have increased with time. Three pulses lasting a few months can be recognised with discharge rates reaching 3 to 8 m3/s. Short term pulsations in growth lasting a few days reach discharge rates of over 10 m3/s and there are periods of days to a few weeks when dome growth is <0.5 m3/s. Discharge rate increased from May 1997 with an average rate of 7.5 m3/s to December 1997. The observations indicate an open magmatic system. ¿ 1998 American Geophysical Union