Monowai Cone (pictured below) is an undersea volcano north of New Zealand. It is probably the world's most active, making it a good model system for studying how submarine eruptions cause landslides, and how both of these can trigger tsunamis. Bill Chadwick at Oregon State University in Newport and his colleagues have measured Monowai Cone's topology in 1998, 2004 and 2007 and have compared the timing of its build-up and collapse with data from the Polynesian Seismic Network.
Between 1998 and 2004 there were nine swarms of 'T waves' — indicators of explosive eruptive activity — of which the biggest was linked to a collapse. But another large collapse occurred between 2004 and 2007 when no anomalous T-waves were recorded — possibly owing to limitations of the monitoring network. The authors say that this is the first study of its type and that more effort should be spent monitoring undersea volcanoes.