its hard to say that it erupting!!  the park is in a giant caldera.  the hot springs and geysers are ground water that is super heated by the remnants of former eruptions.  the Norris basin is more active this year than in the recent past, a dome has been mapped in yellostone lake and thermal anamolies have been identifeied in several other basins.  i was there for two weeks in Aug - no sweat.