Merapi Update for 10/29/2010: Lava flows from the crater

Merapi is showing no signs of slowing down, but some of the eruptive activity has changed in its character. The first reports of lava at the summit area came in overnight, meaning that this eruption that, thus far, had been dominantly explosive is taking on a more effusive character. This might suggest [speculation] that the initial explosions were clearly out a slug of magma that was highly charged with gases at the top of the conduit – popping a cork, almost – and now less volatile-rich (thus less explosive) magma is making its way to the surface [/speculation]. This might mean that the eruption will be “less hazardous” to the surrounding area if the eruption remains lava flows (however, if domes of lava build, the threat of pyroclastic flows still remains high from dome collapse). You can see the lava on many of the most recent photos of the volcano (see below). Don’t be fooled: although lava is erupting, there does appear to be significant ash production as well.

Merapi erupting on October 29, 2010. Lava flows can be seen in the summit crater.

The volcano has had at least 6 explosions over the last 24 hours and more evacuations of the area around Merapi have been called, bringing the total of potential evacuees to over 65,000. National Geographic has a set of images showing the damage the ash fall from Merapi has caused over the last 4 days – including collapsed roofs and damaged vegetation (but I wouldn’t go as far as to call it a “modern Pompeii” as National Geographic does). Here are also some great images from Reuters of the pyroclastic flows from Merapi (see top left image – click to see a larger version). In the shot, you can clearly see the cloud hugging the ground as a flow, but also generating a plume above it – the so-called “co-ignimbrite plume” where the fine ash settles on the pyroclastic flow deposit after the flow has passed. Eruptions reader James Reynolds has also posted some of his own images of explosive character of Merapi – stunning stuff. UPDATE: Here is some video of the volcano as well (from James).

UPDATE at ~2PM Eastern Time: Reports from the area, including from James Reynolds who is on site, suggest that a new, significant explosive event has occurred (see his comment.)

UPDATE: Here is one of the first articles on the new explosion – looks like heavy ashfall upwards of 25 km / 12 miles from the volcano. Also, the Jakarta Globe has a fear-mongering piece on other active volcanoes in Indonesia.

UPDATE: Eyewitness reports on the new eruption.

More updates as they arrive.

{Special thanks to the Eruptions readers who provided links to this post.}

Top left: A pyroclastic flow on Merapi on October 29, 2010.