I'm always amazed by the number of volcanic eruptions captured by satellites that we might not have ever even had known occurred otherwise. Case in point is Rabaul on the island of New Britain in Papua New Guinea. An Aqua satellite captured this shot of Rabaul erupting on May 20th, leaving a gorgeous plume heading off into the Pacific. Sure, most likely someone might have noticed the eruption, but its good to see that we can find eruptions going on even when we're not really looking.
Rabaul is a caldera volcano that is most famous for the simultaneous eruptions of Vulcan and Tavurvur in 1994 that prompted the evacuation of the Rabaul (the city), ranking as a VEI 4 eruption. The volcanic system has been continuously erupting since 2006.