The log of the median time for eruptions in each magnitude bin. The full dataset inclusive of historical data is shown in red, and the geological data beyond 1 ka only is shown in blue. The overlap in the data at M ≥ 7 is due to the long return periods for such eruptions, hence the dominance of the geological data. The purple dashed line indicates the mid-point of the Quaternary. T50 values lying at or close to this line would indicate perfect recording levels.