Global Volcano Hazard Frequency and Distribution is a 2.5 by 2.5
minute gridded data set based upon the National Geophysical Data
Center (NGDC) Volcano Database spanning the period 79 through 2000.
This database includes nearly 4,000 volcanic events categorized as
moderate or above (values 2 through 8) according to the Volcano
Explosivity Index (VEI). Most volcanoes are georeferenced to the
nearest tenth or hundredth of a degree with a few to the nearest
thousandth of a degree. To produce the final output, the frequency of
a volcanic hazard is computed for each grid cell, with the data set
consequently being classified into deciles (10 classes of
approximately equal number of grid cells). The higher the grid cell
value in the final output, the higher the relative frequency of
hazard posed by volcanoes. The dataset is a result of the
collaboration among the Center for Hazards and Risk Research (CHRR) ,
and the Columbia University Center for International Earth Science
Information Network (CIESIN).