The turbulent Dukono volcano, located north of Halmahera island in the Moluccas, let again talking about him since mid-January.
Darwin VAAC alerts have succeeded on January 14, 2015, with a plume rising to 2,100 m., and on January 19, with a plume to 2,700 m. The alert of 21 January / orange aviation code indicates abundant ash emissions identified by MTSAT-2 and the extension of the plume to the southwest to 50 km.
To the left, location of Dukono in the Moluccas archipelago - right, geological map of the island of Halmahera and his active volcanoes - a click to enlarge - Doc. GVP
The Dukono shows an eruptive activity more or less continuously since 1933. This volcano complex present a low profile, with multiple peaks and overlapping craters; active areas are Malupang Magiwe and Malupang Warirang, the latter characterized by a crater 700 meters by 570. (GVP)
This volcano has some peculiarities as to its geology and local tectonics.
It is located on the island of Halmahera, geologically divided into two provinces, the western and the eastern.
The western province is part of a young volcanic field that extends from Morotai through the northern part of Halmahera, Ternate and Tidore, Bacan up.
All volcanoes considered as active and other older, are located in this western province. The area is largely covered by volcanic or sedimentary rocks, recent of from Neogene. The rocks of the basement, exposed south of the island of Bacan, are basic to ultrabasic with crystal inlays. The basement of the SW arm of Halmahera is composed of volcanic and volcaniclastic rocks in association with intrusive igneous rocks; they are exposed on the west side.
Tectonics of the Sulawesi-Maluku region: Sangihe and Halmahera volcanic arc characterize a double subduction of oceanic microplate of the Mollucas. A: current situation - B: Situation there are 5 Ma - Doc Hall / 2000 / geology.um.maine.edu
Tectonics of the area is complex and involves several microplates including that of Halmahera, of Sangihe, Bird's Head and the Moluccas.
The Molucca Sea is the only current example of closure of an oceanic basin by a subduction of oceanic lithospheres in opposite directions, resulting in the creation of the Sangihe arc to the west and the Halmahera arc to the east.
The oceanic plate Maluku was originally part of the Philippine plate, there are 13 Ma, at a time when the Australian plate was further south. The Sangihe trench was active at that time, with a subduction dating from the Oligocene and older than that of Halmahera. The depth of the descending slab of the subduction zone Sangihe is greater than that which characterizes the subduction zone of Halmahera. The two plates, Sangihe and Halmahera, overlapping the plate from the Molucca Sea ... that will disappear eventually.
In the Molucca Sea, the Sangihe subduction absorbs a significant part of 10 cm / year of convergence Philippines / Sunda. GPS displacement speed of 80 mm / year north of the equator.
In the South Moluccas region south of the equator, this speed is rapidly depreciates at a rate of about 2 mm / year.
Below are two videos showing the activity of Dukono in 2014 by the site Photovolcanica.