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).
