Pyroclastic Flow Deposits From the Paluweh Eruption

The crumbling lava dome at Paluweh in Indonesia, seen on December 1, 2012. The collapse of a dome such as this may be the cause of the February 2, 2013 explosive eruption at Paluweh. Image: Tom Pfeiffer / Volcano Discovery. Over the weekend, the fairly remote Indonesian volcano Paluweh (also known as Rokatenda) erupted. Now, the size of the eruption is somewhat unclear due to its location on Palu'e Island, north of Flores Island. Early VAAC reports suggested ash as high as 43,000 feet / ~13 km, however reports from on the ground put it closer to 13-16,000 feet / 4-5 km. Now, that is a sizable difference and possibly the early VAAC reports from satellite and aerial observations got the height wrong -- but in any case, the volcano did experience a notable explosive eruption. Ash fell on towns on the nearby island of Flores, with thicknesses in the millimeters (so noticeable but not very hazardous). The island had been evacuated (~10,000 villagers) earlier last year after the volcano showed signs of unrest. UPDATE 1:45 PM EST: I've added a third image after Simon Carn pointed out that the second image was taken before, not after, the explosive eruption this weekend at Paluweh. A dome had been growing at Paluweh since at least November 2012, and as we've seen before at other volcanoes, these lava domes can oversteepen and collapse as image taken by Tom Pfeffier of Volcano Discovery clearly shows (above) as lava intrudes from underneath and pushes the dome outward. Two things happen when the dome collapses -- first, a pyroclastic flow forms from the rubbles of the collapsed dome (typically the material is still hot) and if pressure was building under the dome from degassing magma, an explosive eruption can occur when the pressure drops from the loss of the dome. This is my guess of what happened over the weekend at Paluweh and lucky for us, we have satellite imagery to support it.