Locutus of Gourd wrote:
But to have an earthquake (which triggered the fatal tsunami) and an unrelated fatal volcanic eruption hit within the span a single day is unbelievably bad luck.
Actually, it wouldn't surprise me if the eruption was related to the earthquake - I can see the earthquake causing a shift that opened up a path for the volcano to start spewing, and the island isn't that big.
They were different islands: Java for the volcano and the Mentawai Islands off of Sumatra for the earthquake and tsunami, which are about 1300 kilometers apart.
Seismologists said that there's no evidence that the two events are related. Merapi is one of the most active volcanoes in Indonesia (which has 129 other active volcanoes), having erupted and caused fatalities in 2006, 1994, and 1930 with other more minor eruptions in between. This eruption was described as the volcano undergoing a large but relatively common release of pent up pressure, possibly in anticipation of a larger eruption in the near future, depending on whether it forms a lava dome or not.