Research Papers
Effects of the 1995/96 Ruapehu eruptions: has the seismicity changed?
CJ Bryan and S Sherburn - IGNS
High quality seismic data were collected on Ruapehu volcano in 1994 and 1998. These data bracketed the 1995-96 eruptions, the largest eruptions of Ruapehu in 50 years.
Analysis of these data showed a clear difference in the frequency content of some of the seismic signals. In particular, a new low-frequency signal in some of the earthquakes and tremors was observed in 1998. This new signal, which probably first appeared during or soon after the 1995-96 eruptions, remains as of this time (May 2000).
It most likely resulted from changes in the volcanic plumbing system and has significant implications for forecasting and real-time assessment of future eruptive activity at Ruapehu.