VOLCANO MADNESS: [Geology2] Mount Rokatenda (Paluweh) Volcano

Monday, August 12, 2013

[Geology2] Mount Rokatenda (Paluweh) Volcano

August 11, 2013

Mount Rokatenda (Paluweh) Volcano, Indonesia, erupts; six dead

Mount Rokatenda in eruption
Photo from BBC.com here

Mount Rokatenda*** north of the island of Flores in Indonesia erupted on August 10, killing 6 people. It has been erupting since late 2012. Eruptions were generally VEI 3 in intensity. A 3 km exclusion zone was set up, and many residents of the island (~3000? according to an AP story) were evacuated, with many moving to the main island of Flores, but some refused to leave, growing used to the moderate volcanic activity.

Paluweh and its eruption centers
Originally from Neumann van Padang, 1930
as reproduced in his 1983 article

Scientific literature about this volcano is sparse, and the best that I found was "History of the volcanology in the former Netherlands East Indies" by Neumann van Padang, Scripta Geol. 71, pp. 1- 75, 1983. Reading this paper, with its four beautiful color plates brought back memories of the two famous photographers of volcanoes, Katya and Maurice Kraft who were killed in a pyroclastic flow during the eruption of Mount Unzen. Katya and I had roomed together at a field conference in the Caribbean.

The first sighting of this volcano appears to have been in 1856 by Francis, who called it Luca Raja; Buddingh in 1861 called it Palowe. When spotted by Kemmerling in 1921 it has a "partly barren, partly wooded summit."

Paluweh rises 3,000 meters from the sea floor, and is 875 m high above the water. It has the classic, though somewhat asymmetrical, stratovolcano conical structure though appears highly gullied from the topo map in Padang's figure 13. The summit region has a complex of small cones. These appear to be somewhat south of the main summit (see figure to the right). Documented eruptions were in ~1650, 1928, and 1972.

March 31, 2013 NASA image of Paluweh/Rokatenda
showing devastation on the south side of the island

##. Ash and pumice, estimated at 19.5 million cubic meters (corresponding to about 4.6 million cubic meters of lava) were erupted, and a new lava dome of about 8 million cubic meters as formed.
Paluweh erupted in August-September 1928. The eruptions took place from a collapsed area south of the summit where six ancient craters and three lava domes had been found. During the August eruption three new craters were formed, and a fourth on September 9th. During the august eruptions there were "sea waves" with heights of 5-10 m (tsunamis) that attacked the island itself, killing 128 people out of the total population of 266.

Flores is near the eastern end of the Indonesian arc, west of East Temor and northwest of Darwin, Australia. The geology of Indonesia is extremely complicated. It lies at the intersection of three of the major lithospheric plates: the Indo-Australian Plate, the Philippine Plate, and the Eurasian Plate. These plates intersect at angles, leading to a complex network of faults in the region (and to the intense earthquakes that plague the area). These collisions produce deep trenches (Java, Timor, and Philippines Trenches) and island arc volcanoes.

Simplified plate boundaries in Indonesia.
From here.
Although blurry, Flores can be seen just above the
intersection of the Java and Timor Trenches.

***In researching this, I found different spellings: Rokatinda, Paluweh, Paloweh, Palu'e, Luca Raja, Palowe. In the article referenced above, I think that the stratovolcano and the island that it occupies are referred to as Paluweh, and the summit crater as Rokatenda and I follow that nomenclature here. The "Palu..." names were Dutch origin; the Rokaa... names were the new Indonesian names. It is about 1250 miles east of Jakarta.

##The population now is estimated as about 10,000.

Here are other references to this volcano: The Smithsonian Global Volcanism Program here.
Volcano Discovery here.

Posted by Susan W. Kieffer

http://www.geologyinmotion.com/2013/08/mount-rokatenda-paluweh-volcano.html
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