Awu Volcano | John Seach


Sangihe Islands, Indonesia

3.67 N, 125.50 E
summit elevation 1320 m

Awu is the northern most volcano in the Sangihe Islands, Indonesia. Four evenly spaced volcanoes (~ 50 km) make up the Sangihe Islands. Awu is located in the north of Sangihe Island (Palau Sangihe). It rises to a height of 1320 m and 3300 m above the ocean floor.

The summit contains an oval-shaped crater which is 390 m deep (1150 m x 1200 m) and elongated in a north-south direction. Rain water accumulates in the crater to form a lake. The lake has a range in depth of 5-34 m, and covers an area of 208,640 sq m.

Awu volcano is one of the most dangerous in Indonesia. Since 1711 more than 8000 people have been killed by eruptions. In June 2004, more than 16,000 people were evacuated from the slopes of Awu volcano. This crater has been the focus of recent activity with fifteen eruptions since 1640, most of which were explosive.

The character of eruptions at Awu volcano are similar to that of Kelud volcano in East Java. Eruptions threaten people living on the island.

Two submarine edifices at least 1000 m high are located in the strait immediately north of Awu volcano. One, with crest at 206 m, is surrounded by a circular platform 300m deep which represents a fringing reef from a sunken island. The other, lacking such a platform, appears relatively young and may be parasitic to Awu volcano. It has a summit crater or small caldera, about 800 m across and breached to the northwest.

2015 Unrest
Awu volcano was raised to level 2 alert (Waspada) on 24th November 2015 due to shallow volcanic earthquakes. A 3 km radius exclusion zone was placed around the volcano.

2004 Eruption
Between 6 to 8 June, more than 17,000 people were evacuated from areas surrounding the volcano (out of 27,000 at risk). Evacuations were 12,065 from Tahuna, 5,690 from Kendahe, and 9,248 from Tabukan Utara. Evacuees were sheltered in schools and churches in Tahuna, the main town on Sangihe, 15 kilometres from the volcano's crater. A magmatic eruption recorded on 7 June, followed by another eruption of hot ash on 9th June at 5:12 am. A larger eruption occurred on 10th June with ash ejected to a height of 3300 m. The island's airport was closed and authorities blocked roads leading to the mountain. Darwin Volcanic Ash Advisory Center issued 15 advisories for Awu volcano during June 2004. On 13th June, the alert level was downgraded and most evacuees were allowed to return to their homes.

1992 Eruption
In February the lake pH dropped from 5 to 2. On the 1st February there was a sudden draining of 80% of the lake. In the SE part of the crater, a deep vent 20 m in diameter, was surrounded by ejecta, indicating it had been formed by a phreatic eruption. This eruption presumably ejected water from the crater.

1968 Earthquake and Avalanches
On 10th August 1968 an earthquake and tsunami killed many people on the Northern Celebes island of Tuguan. Earthquakes possibly related to this caused avalanches from the inner crater wall of Awu volcano into the lake.

1966 Eruption
An eruption on 12th August produced pyroclastic flows which killed 39 people and displaced 11,000 from surrounding slopes.

1856 Eruption
On 2nd March 1856 an eruption began at Awu volcano. A loud noise was heard between 07:00 and 08:00 hr accompanied by lava flows which reached the sea. The eruption killed 2806 people.

The eruption was described in a newspaper article in Sydney Morning Herald 11th Nov 1856. "... the crashing of thousands of trees torn up and carried away, was followed about an hour later by pearls of thunder which shook the ground and deafened the ear. A black column of stones and ashes then shot up from the mountain to an immense height and fell, illuminated by the glare of the lava like a shower of fire...Large stones were hurled through the air, crushing whatever they fell upon. Houses and crops which had not been destroyed by fire sunk and disappeared beneath the ashes and stones..."

Further reading
Morrice, M. G., et al. "An introduction to the Sangihe arc: Volcanism accompanying arc—arc collision in the Molucca Sea, Indonesia." Journal of Volcanology and Geothermal Research 19.1-2 (1983): 135-165

Awu Volcano Eruptions

2004, 1992, 1968?, 1966, 1930-31, 1922, 1921, 1913, 1893, 1892, 1885, 1883, 1875, 1856, 1812, 1711, 1646, 1640-41