Magnitude 5.9 Earthquake beneath Posi Posi Rao Island, North Maluku Province, Indonesia.

The United States Geological Survey recorded a Magnitude 5.9 Earthquake at a depth of 20.3km, beneath the northern part of Posi Posi Rao Island in the North Maluku Province of Indonesia, slightly slightly after 1.05 am local time on Sunday 19 November 2017 (slightly after 4.05 pm on Saturday 18 November, GMT). There are no reports of any casualties associated with this event, but it did cause some minor damage to buildings in Posiposi village, on the south part of the island.

Damage to buildings on Posiposi Rao Island following the 19 Novenmber 2017 Earthquake. Earthquake Report.

Posiposi Rao lies at the northern end of the Halmahera Islands chain, a volcanic arc formed where one tectonic plate is being subducted beneath another, with the underlying plate being melted by the heat of the Earth's interior, and lighter minerals bubbling up through the overlying plate to form volcanoes. However the Halmahera Islands are unusual in that they lie on a double subduction zone. The underlying plate, a northeaster extension of the Molucca Sea Plate, is being overridden form the Philippine Plate from the east and the Eurasian Plate from the west. The Halmahera volcanoes are located where the Philippine Plate is overriding the Molucca Sea Plate; to the west the Sangihe Islands lie where the Molucca Sea Plate is being overridden by the Eurasian Plate.

 Diagrammatic representation of the subduction zones beneath Halmahera (middle), plus the Philippines (top) and Sulawesi (bottom), with the Eurasian Plate to the left, the Molucca Sea Plate in the middle, and the Philippine Plate to the right.  Hall & Wilson (2000).

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

The approximate location of the 19 November 2017 Posiposi Rao Earthquake. USGS.

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Magnitude 6.2 Earthquake off the north coast of Morotai Island.

The Indonesian Baden Meteorologi, Klimatologie, dan Geophysica (Meteorological, Climatological and Geophysical Agency) recorded a Magnitude 6.2 Earthquake at a depth of 11 km off the north coast of Morotai Island in the Halmahera Islands, slightly after 10.30 pm local time (slightly after 1.30 pm GMT) on Tuesday 19 November 2013. There are no reports of any damage or casualties, but this was a large quake and is likely to have been felt across the island.

The approximate location of the 19 November 2013 Morotai Island Earthquake. Google Maps.

The Halmahera Islands arc a volcanic arc; formed where one tectonic plate is being subducted beneath another, with the underlying plate being melted by the heat of the Earth's interior, and lighter minerals bubbling up through the overlying plate to form volcanoes. However the Halmahera Islands are unusual in that they lie on a double subduction zone. The underlying plate, a northeaster extension of the Molucca Sea Plate, is being overridden form the Philippine Plate from the east and the Eurasian Plate from the west. The Halmahera volcanoes are located where the Philippine Plate is overriding the Molucca Sea Plate; to the west the Sangihe Islands lie where the Molucca Sea Plate is being overridden by the Eurasian Plate.

Sea also Magnitude 5.7 Earthquake of the north coast of Sulawesi, Explosive eruption on Mount Lokon, Eruption on Gamalama, Earthquake hits Sulawesi and Volcanic activity in the Halmahera Islands.

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Stricken tanker spills fuel oil in Ternate port, North Maluku Islands.

An oil tanker has sunk in the Port of Ternate, on Ternate Island in the North Malaku Group in Indonesia, after being struck be a freak wave. The Patriot Andalan, operated by state-owned oil company Pertamina was unloading its cargo of petrol and diesel, when the wave lifted the vessel onto a jetty, causing severe damage that resulted in the vessel capsizing and sinking. The tanker was carrying 5000 tonnes of diesel fuel and 2000 tonnes of petrol from a refinery in West Papua, of which 1000 tonnes of diesel and 600 tonnes of petrol had been unloaded when the vessel sank. It is unclear how much of the remaining oil has leaked into the sea.

The stricken Patriot Andalan on Wednesday 31 July 2013. Liputan6.

There are no reports of any casualties due to the incident, and Pertamina have assured residents of the island that there is no danger of fuel shortages occurring, but it is unclear what impact the spill will have on the local environment, potentially up to 6400 tonnes of oil could leak from the vessel (though it is likely that some of this will remain on the vessel, which was split into a number of compartments, not all of which are likely to have been breached) and Pertamina are reportedly tackling the spill largely through the use of chemical dispersants, which are themselves thought to be lethal to many forms of marine life.

The Malaku Islands form part of the Coral Triangle, a biodiversity hotspot known as the 'Amazon of the Seas', which is home to around 30% of the world's coral reefs, as well as six of the world's seven marine turtle species and over 2000 species of fish, many of them highly endemic.

The location of the Port of Ternate. Google Maps.

See also Oil spill devastates popular Thai tourist resort, Nigerian sailor survives two days in sunken oil service vessel, Collision leads to oil spill on swollen Mississippi, Oil barge explosion in Port of Lagos and Building an artificial Coral Reef on Pulau Weh, Indonesia.

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