Figure 8: Maps showing the variation in probability of volcanic eruptions across the
  YMR calculated using method 2. As in Figure 5, the logarithm of probability of a
  volcano forming within a 8 km2 area during the next 10,000 years is contoured
  using h = 20 kmand all volcanoes in data set 1 formed less than 5 Ma (a) and h =
  20 km and all volcanoes in data set 2 formed less than 2 Ma.The contour interval is
  0.25 log(P[N=1, 10,000 yr]) (e.g., -4 is a probability of 1 x 10-4 of a new volcano
  forming within an 8 km2 area in 10,000 years), and other symbols are as in Figure
  5.