The hazard posed by small-volume basaltic volcanism to the proposed Yucca Mountain nuclear waste repository in Nevada has been a topic of scientific debate for well over a decade. In the past few years, debate has focused on the extent and age of buried volcanoes in alluvial-filled basins of the Yucca Mountain region (YMR) and their potential impact on volcanic hazard estimates.

To address this issue, the U.S. Department of Energy (DOE) has sponsored an exceptionally high resolution aeromagnetic survey completed in 2004, and a presently ongoing drilling program to characterize the location, age, volume, and chemistry of buried basalt in the YMR (Figure 1). DOE has convened an expert panel that will use this information to update probabilistic volcanic hazard estimates originally obtained by experts in 1996. Partly on the basis of the unknown extent of buried volcanoes, Smith and Keenan [2005] suggested that volcanic hazard estimates might be 1–2 orders of magnitude higher than estimated by the 1996 expert elicitation.