Distributions of archeological and volcanic data over the past 50 ka.(a-d) Data distribution through time in 500 year bins comparing archeological and volcanic sources for (a) all data, (b) intensity, (c) inclination, and (d) declination. (e) Distribution of α
95 in 1° bins and (f) intensity uncertainties in 1 μT bins. White bars show all data, light gray show archeological data only and dark gray show volcanic data only. The numbers of specific data types are noted on the graph labels. There are less data for the intensity uncertainties than for the intensities as not all intensity data has been reported with an associated uncertainty.