Figure 2. Volcanic eruption regime. a) Indicates the thick of tephra layers deposited into the Lake Relem. Grey horizontal line shows arbitrary threshold of >1.5 cm to determine relevant eruptions (red crosses). b) Tephra thickness modelled as the exponential decay after eruption. c) Eruption frequency every 1000 years. Grey points indicate the sum of frequency every 1000 years. Trend of frequency was obtained by smooth spline function (blue line) with spar =0.7.