Two new studies to decode Auckland’s volcanic past have been published, and they show volcanic activity was quite temperamental. At one stage several large eruptions happened within 4,000 years, contrasted with thousands of years or more of silence. And scientists say at least half of all the eruptions happened in the past 60,000 years, which is a short time-frame, and shows an increase in the rate of eruptions. The studies were published this month by work from the Determining Volcanic Risk in Auckland research programme. Dr Graham Leonard from GNS Science led the research team.