Islands evacuated after major eruption on Mount Ruang, Indonesia.

The Indonesian Meteorology, Climatology and Geophysics Agency has reported a major series of eruptions on Mount Ruang, an island volcano at the southern tip of the Sangihe Islands, which has prompted the evacuation of both Ruang Island and the nearby Tagulandang Island, more than 12 800 people in total. The volcano erupted three times on Tuesday 30 April 2024, producing ash columns which rose to more than 5 km above sealevel, and drifted west as far as Borneo. Seven airports in Indonesia have been forced to close temporarily due to the dangers of ash from the volcano.

An eruption on Mount Ruang, Indonesia, on 30 April 2024, seen from Tagulandang Island. Endha Reifel Pontoh/Reuters.

The Sangihe Island Arc is a chain of volcanic islands running between the northern tip of Sulawesi and the southern tip of Mindanao. The chain marks the boundary between the Molucca Plate to the east and the Sangihe Plate to the west, with the Molucca Plate being subducted beneath the Sangihe Plate. As the Molucca Plate sinks into the Earth it is heated by the friction and the heat of the planet's interior, causing it to partially melt. Some of the melted material then rises through the overlying Sangihe Plate as magma, fuelling the volcanoes of the Sangihe Arc.

The subduction zones beneath Sulawesi and the surrounding islands. Hall & Spakman (2015).

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Eruption on Mount Karangetang triggers pyroclasitc flow.

Authorities on the Indonesian island of Siau, in the Sangihe Archipelago to the north of Sulawesi, have extended an exclusion zone around Mount Karangetang, a 1784 m high stratovolcano (cone-shaped volcano) on the northern end of the island, following a pyroclastic flow (flow of heavy superheated gas containing large amounts of hot ash, rocks and debris) on Tuesday 5 February 2019, which blocked a road on the island. Mount Karangetang is one of Indonesia's most active volcanoes, typically erupting several times per year, with the current phase of eruptions having begun in November 2018, after several months of inactivity.

Pyroclastic flow blocking a road on Siau Island, Indonesia on 5 February 2019. 3 alacarta.

Siau Island is quite densely populated with around 22 000 permanent residents, and Mount Karangetang frequently causes problems for the islanders, having most recently caused fatalities in August 2010. The Sangihe Island Arc is a chain of volcanic islands running between the northern tip of Sulawesi and the southern tip of Mindanao. The chain marks the boundary between the Molucca Plate to the east and the Sangihe Plate to the west, with the Molucca Plate being subducted beneath the Sangihe Plate. As the Molucca Plate sinks into the Earth it is heated by the friction and the heat of the planet's interior, causing it to partially melt. Some of the melted material then rises through the overlying Sangihe Plate as magma, fuelling the volcanoes of the Sangihe Arc.

 The subduction zones beneath Sulawesi and the surrounding islands. Hall & Spakman (2015).

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Eruption on Mount Soputan, Sulawesi.

The Volcanological Survey of Indonesia has reported a major new eruption on Mount Soputan, a highly active stratovolcano (cone-shaped volcano made up of layers of ash and lave) on northern Sulawesi. The agency began to detect seismic events (tremors) beneath the volcano at about 5.00 pm local time on Saturday 15 December 2018, which increased slowly overnight, with minor eruptive activity beginning at about 1.00 am, with lava fountains beginning at about 3.10 am. At about 5.40 am the volcano began to erupt far more energetically, producing an ash column that rose to about 8.8 km above sealevel.

An ash column over Mount Soputan, Sulaweisi, on the morning of Sunday 16 December 2018. Badan Nasional Penanggulangan Bencana.

Soputan is a small volcano in the Tondano Caldera located near the eastern tip of the northern arm of Sulawesi. The volcanoes of the northern arm of Sulawesi are located at the southern end of the Sangihe Volcanic arc, where an extension Molucca Sea Plate is being subducted beneath an extension of the Eurasian Plate, sometimes called the Sangihe Plate. As this happens part of the subducting plate is melted by the heat of the Earth's interior, and rises up through the overlying plate as liquid magma, forming volcanoes at the surface. About 320 km to the east, the Molucca Plate is also being subducted beneath an extension of the Philippine Plate, sometimes called the Halmahera Plate, producing a second chain of volcanoes in the Halmahera Islands. At some point in the future the Molucca Plate will vanish and the two volcanic arcs will meet.

The subduction zones beneath Sulawesi and the surrounding islands. Hall & Spakman (2015).

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Eruptions on Mount Lokon Sulawesi.

Mount Lokon, a 1578 m stratovolcano (cone-shaped volcano) on the northeastern tip of Sulawesi, Inodnesia, began erupting at about 3.00 pm local time on Saturday 13 September 2014, for the first time since September 2013. The volcano reportedly produced a column of ash reaching 600 m above the summit, as well as raining ash down on several local towns, where people have reported respiratory problems. Local authorities have set up a 2.5 km exclusion zone around the volcano as a precaution.

Eruption on Mount Lokon. RRI.

Lokon is a double volcano located near the eastern tip of the northern arm of Sulawesi, Indonesia. It has two cone-shaped peaks, Lokon to the southwest and Empung 2.2 km to the northeast, with a saddle of volcanic rock separating the two. Of these Lokon is the larger, though it has not erupted in recorded history, whereas the slightly smaller Empung last erupted in the late eighteenth century. Situated on the saddle between the two summits is Tompaluan, a double crater that remains active to the current day.

The Lokon-Empung volcanic complex is located at the southern end of the Sangihe Volcanic arc, where an extension Molucca Sea Plate is being subducted beneath an extension of the Eurasian Plate, sometimes called the Sangihe Plate. As this happens part of the subducting plate is melted by the heat of the Earth's interior, and rises up through the overlying plate as liquid magma, forming volcanoes at the surface. 320(ish) km to the east the Molucca Plate is also being subducted beneath an extension of the Philippine Plate, sometimes called the Halmahera Plate, producing a second chain of volcanoes in the Halmahera Islands. At some point in the future the Molucca Plate will vanish and the two volcanic arcs will meet.

The location of Mount Lokon, Sulawesi. Google Maps.

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 Explosive eruption on Mount Lokon.

Mount Lokon, a volcano close to the tip of Sulawesi's northern arm, erupted suddenly at about 6.30 am local time on Monday 9 September 2013 (about 10.30 pm on Sunday 8 September, GMT)...

 Eruption on Mount Karangetang.

On 9 April 2013 the Darwin Volcanic Ash Advisory Centre in Australia reported a 4.3 km ash plume rising from Mount Karangetang, a volcano on Siau Island, one of the Sangihe Islands roughly 130 km north of Sulawesi and 260 km south of Mindanao in the Philippines. The plume drifted about 45 km to the northwest of...

 Eruption on Mount Lokon, Sulawesi.

Mount Lokon on northern Sulawesi erupted explosively slightly before 8.00 am local time on Wednesday 20 March 2013 (slightly before midnight on 19 March, GMT), throwing a column of ask 2 km into the sky, according to Badan Nasional Penangulanggan Bencana (Indonesia's Disaster Mitigation Agency). The eruption...

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Explosive eruption on Mount Lokon.

Mount Lokon, a volcano close to the tip of Sulawesi's northern arm, erupted suddenly at about 6.30 am local time on Monday 9 September 2013 (about 10.30 pm on Sunday 8 September, GMT) producing a 1500 m high ash column in an explosive eruption that could be heard 10 km away, according to the Pusat Vulkanologi Dan Mitigasi Becani Geologi (Indonesian Centre for Volcanology and Geological Hazard Mitigation). This is the tenth such eruption since July this year, and a 2.5 km exclusion zone is currently being maintained around the volcano.

An eruption on Mount Lokon in July 2011. Reuters.

Lokon is a double volcano located near the eastern tip of the northern arm of Sulawesi, Indonesia. It has two cone-shaped peaks, Lokon to the southwest and Empung 2.2 km to the northeast, with a saddle of volcanic rock separating the two. Of these Lokon is the larger, though it has not erupted in recorded history, whereas the slightly smaller Empung last erupted in the late eighteenth century. Situated on the saddle between the two summits is Tompaluan, a double crater that remains active to the current day.

The Lokon-Empung volcanic complex is located at the southern end of the Sangihe Volcanic arc, where an extension Molucca Sea Plate is being subducted beneath an extension of the Eurasian Plate, sometimes called the Sangihe Plate. As this happens part of the subducting plate is melted by the heat of the Earth's interior, and rises up through the overlying plate as liquid magma, forming volcanoes at the surface. 320(ish) km to the east the Molucca Plate is also being subducted beneath an extension of the Philippine Plate, sometimes called the Halmahera Plate, producing a second chain of volcanoes in the Halmahera Islands. At some point in the future the Molucca Plate will vanish and the two volcanic arcs will meet.

The approximate location of Mount Lokon. Google Maps.

See also Eruption on Mount Karangetang, Eruption on Mount Lokon, Sulawesi, Eruption on Gamalama, Earthquake hits Sulawesi and Eruptions from the Tompaluan Crater, Lokon-Empung, Sulawesi. 

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Eruption on Mount Karangetang.

On 9 April 2013 the Darwin Volcanic Ash Advisory Centre in Australia reported a 4.3 km ash plume rising from Mount Karangetang, a volcano on Siau Island, one of the Sangihe Islands roughly 130 km north of Sulawesi and 260 km south of Mindanao in the Philippines. The plume drifted about 45 km to the northwest of the island. Karangetang, which is one of Indonesia's most active volcanoes, has been fairly quiet since December 2012, but began a new phase of volcanic activity on 4 April this year, with lava-flows on the flanks of the volcano and ash avalanches reaching as far as 2 km from the summit.

Lava flows on Karangetang on 4 April 2013. ROMY/European Pressphoto Agency/National Geographic.

Karangatang is a 1784 m high stratovolcano (cone-shaped volcano) on the northern end of Siua Island. It has erupted 41 times since written records began on the island in 1675. The island is quite densely populated with around 22 000 permanent residents, and the volcano frequently causes problems for the islanders, having most recently caused fatalities in August 2010.

The Sangihe Island Arc is a chain of volcanic islands running between the northern tip of Sulawesi and the southern tip of Mindanao. The chain marks the boundary between the Molucca Plate to the east and the Sangihe Plate to the west, with the Molucca Plate being subducted beneath the Sangihe Plate. As the Molucca Plate sinks into the Earth it is heated by the friction and the heat of the planet's interior, causing it to partially melt. Some of the melted material then rises through the overlying Sangihe Plate as magma, fueling the volcanoes of the Sangihe Arc.

See also Eruption on Mount Lokon, Sulawesi, Eruption on Gamalama, Volcanic activity in the Halmahera Islands, Fresh eruption on Mount Karangetang, Indonesia and Volcanoes on Sciency Thoughts YouTube.

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Eruption on Mount Lokon, Sulawesi.

Mount Lokon on northern Sulawesi erupted explosively slightly before 8.00 am local time on Wednesday 20 March 2013 (slightly before midnight on 19 March, GMT), throwing a column of ask 2 km into the sky, according to Badan Nasional Penangulanggan Bencana (Indonesia's Disaster Mitigation Agency). The eruption came from the Tomohon crater, which lies on a sadle between the more prominent Lokon and Empung craters, and which has been erupting intermittently since 2011, though this eruption was described as exceptionally loud, shocking local people.

The ash column over Mount Lokon. Viva.

Mount Lokon is on Sulawesi's Northern Peninsula, which forms one end of the Sangihe Volcanic Arc, a string of volcanic islands which runs from Sulawesi to Mindanao Island in the Philippines. The arc is formed as part of the Molucca Plate to the east is subducted beneath the Sangihe Plate to the west. As the Molucca Plate sinks into the Earth, it is partially melted by friction and the heat of the Earth's interior. Some of the melted material then rises through the overlying plate, fueling the volcanoes of the Sangihe Arc.

See also Eruption on Gamalama, Earthquake hits Sulawesi, Eruption on Mount Sirung, Eruptions from the Tompaluan Crater, Lokon-Empung, Sulawesi. December 2011 and Volcanoes on Sciency Thoughts YouTube.

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