Gaua

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  • Vanuatu
  • Vanuatu
  • Stratovolcano
  • 2010 CE
  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 14.27°S
  • 167.5°E

  • 797 m
    2614 ft

  • 257020
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

14 August-20 August 2013

On 14 August the Vanuatu Geohazards Observatory reported that activity at Gaua had increased since June; volcanic tremor levels increased slightly and ash plume emissions continued. The Alert Level remained at 1 (on a scale of 0-4).

Source: Vanuatu Geohazards Observatory



 Available Weekly Reports


2013: April | August
2011: October
2010: January | April | May | June | December
2009: September | October | November | December


14 August-20 August 2013

On 14 August the Vanuatu Geohazards Observatory reported that activity at Gaua had increased since June; volcanic tremor levels increased slightly and ash plume emissions continued. The Alert Level remained at 1 (on a scale of 0-4).

Source: Vanuatu Geohazards Observatory


24 April-30 April 2013

The Wellington VAAC reported that on 29 April a plume from Gaua was observed from an aircraft. Satellite imagery did not indicate ash.

Source: Wellington Volcanic Ash Advisory Center (VAAC)


26 October-1 November 2011

Based on a hazards assessment during 17-18 October, the Vanuatu Geohazards Observatory reported that Gaua had been emitting ash since September. Ash fell on western parts of the island. The Alert Level remained at 1 (on a scale of 0-4).

Source: Vanuatu Geohazards Observatory


5 October-11 October 2011

Vanuatu Geohazards Observatory reported that the seismic network monitoring Gaua detected volcanic activity in August. Gas plumes were detected by the OMI satellite on 17, 27, and 28 September, and ashfall was reported in the N, E, and W parts of Gaua on 10 October by local authorities. The Alert Level remained at 1 (on a scale of 0-4).

Source: Vanuatu Geohazards Observatory


29 December-4 January 2011

On 21 December, the Vanuatu Geohazards Observatory reported that volcanic activity from Gaua had been low since September. Recent observations indicated that the near-vent vegetation and vegetation exposed to trade winds on the W side of the island was again growing. Seismic data showed a decreasing number of events. The Alert Level was lowered to 1 (on a scale of 0-4).

Source: Vanuatu Geohazards Observatory


16 June-22 June 2010

Based on information from the Vanuatu Geohazards Observatory, the Wellington VAAC reported that during 16-19 June ash plumes from Gaua rose to an altitude of 3 km (10,000 ft) a.s.l. On 19 June the plume drifted more than 90 km W.

Source: Wellington Volcanic Ash Advisory Center (VAAC)


9 June-15 June 2010

Based on information from the Vanuatu Geohazards Observatory, the Wellington VAAC reported that on 7 June an ash plume from Gaua rose to an altitude of 3 km (10,000 ft) a.s.l.

Source: Wellington Volcanic Ash Advisory Center (VAAC)


26 May-1 June 2010

Based on information from the Vanuatu Geohazards Observatory, the Wellington VAAC reported that on 26 May an ash plume from Gaua rose to an altitude of 3 km (10,000 ft) a.s.l.

Source: Wellington Volcanic Ash Advisory Center (VAAC)


19 May-25 May 2010

Based on information from the Vanuatu Geohazards Observatory and analyses of satellite imagery, the Wellington VAAC reported that during 18-19 and 21-22 May ash plumes from Gaua rose to an altitude of 3 km (10,000 ft) a.s.l. and occasionally drifted W.

Source: Wellington Volcanic Ash Advisory Center (VAAC)


12 May-18 May 2010

Based on information from the Vanuatu Geohazards Observatory, the Wellington VAAC reported that on 11 May an ash plume from Gaua rose to an altitude of 3 km (10,000 ft) a.s.l.

Source: Wellington Volcanic Ash Advisory Center (VAAC)


5 May-11 May 2010

On 11 May the Vanuatu Geohazards Observatory reported that field observations of Gaua revealed continued activity during April through the beginning of May. Significant emissions of gas and ash caused damage to vegetation around the crater and in areas on the NW, W, and SW parts of the island, the dominant wind directions. Lahars on the W part of the island were seen in April. Seismic data revealed that tremors had become more frequent since the beginning of the year. The Vanuatu Volcano Alert Level (VVAL) remained at 2 (on a scale of 0-4).

Source: Vanuatu Geohazards Observatory


28 April-4 May 2010

Based on information from the Vanuatu Geohazards Observatory, the Wellington VAAC reported that on 29 April and 2 May ash plumes from Gaua were seen on satellite imagery drifting W and NW at an altitude of 3 km (10,000 ft) a.s.l.

Source: Wellington Volcanic Ash Advisory Center (VAAC)


14 April-20 April 2010

Based on analysis of MODIS satellite imagery and information from the Vanuatu Geohazards Observatory, the Wellington VAAC reported ash plumes from Gaua during 13-16 and 19-21 April. The plumes regularly rose to altitudes of 3 km (10,000 ft) a.s.l. The advisories on 14-15 April noted that the plumes were mostly steam. A spokesman for the Vanuatu Disaster Management Office described the activity as "huge, dark plumes" in an AAP news report.

Sources: Vanuatu Geohazards Observatory, Wellington Volcanic Ash Advisory Center (VAAC), Australian Associated Press


7 April-13 April 2010

On 7 April, the Vanuatu Geohazards Observatory reported that recent field observations of Gaua confirmed significant changes in activity. Gas plumes were detected daily by satellite images. During the end of March through the beginning of April, ash plumes rose daily to altitudes of 2.1-3 km (7,000-10,000 ft) a.s.l. Explosions were heard in nearby villages. Starting on 3 April villagers living in the N and S parts of the island reported ashfall and saw bombs ejected from Gaua. Based on Vanuatu Geohazards Observatory information, the Wellington VAAC reported that during 8-12 April ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. Ash plumes were seen on satellite imagery on 11 and 12 April drifting S and SE. The Vanuatu Volcano Alert Level (VVAL) remained at 2 (on a scale of 0-4).

Sources: Vanuatu Geohazards Observatory, Wellington Volcanic Ash Advisory Center (VAAC)


27 January-2 February 2010

On 29 January, the Vanuatu Geohazards Observatory reported significant changes in Gaua's activity over the previous two weeks. They noted that since 16 January more gas was emitted and multiple explosions produced denser and darker ash plumes. During 22-29 January, the water level in the river to the E that Lake Letas feeds rose 10 cm. Gas-and-ash plumes rose 3 km and drifted S and W. On 24 January nearby villagers reported seeing ejected material from Strombolian activity. The Wellington VAAC reported that on 27 January an ash cloud was seen on satellite imagery. Strong explosions were seen and heard from East Gaua on 29 January. According to the VAAC, the Vanuatu Geohazards Observatory reported that gas-and-ash plumes rose to altitudes of 3 km (10,000 ft) a.s.l. and drifted S and W that same day.

Sources: Vanuatu Geohazards Observatory, Wellington Volcanic Ash Advisory Center (VAAC)


20 January-26 January 2010

Based on analyses of satellite imagery and pilot observations, the Wellington VAAC reported that on 21 January an ash plume from Gaua rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted S. An ash cloud was seen in satellite imagery on 26 January.

Source: Wellington Volcanic Ash Advisory Center (VAAC)


13 January-19 January 2010

On 13 January, Vanuatu Geohazards Observatory reported that ash emissions that had become denser and darker on 14 December continued. Ashfall persisted in the W part of the island and satellite imagery showed gas emissions. The Vanuatu Volcano Alert Level (VVAL) remained at 2 (on a scale of 0-4).

Source: Vanuatu Geohazards Observatory


16 December-22 December 2009

On 14 December, Vanuatu Geohazards Observatory reported that activity from Gaua during the previous month was characterized by continuous ash emissions accompanied by periodic steam emissions. Ashfall was reported in the W part of the island. Satellite imagery revealed that periods of significant gas emissions were more frequent than during November. Ash emissions during 14-18 December were thicker and darker, and possibly represented a new eruptive phase. Ash plumes continued to drift W and produce ashfall. The Vanuatu Volcanic Alert Level remained at 2 (on a scale of 0-4).

Source: Vanuatu Geohazards Observatory


25 November-1 December 2009

The Vanuatu Geohazards Observatory reported that a large explosion from Gaua's Mount Garat on 18 November was followed by high dense ash plumes. Seismicity increased on 25 October and remained significant through 24 November. According to news articles, an explosion that caused ashfall in inhabited areas on 26 November prompted the evacuation of more than 300 people. The Alert Level was raised to 4, the second highest level on a scale of 0-5.

Sources: Vanuatu Geohazards Observatory, Agence France-Presse (AFP)


14 October-20 October 2009

On 13 October, Vanuatu Geohazards Observatory confirmed that Gaua's Mount Garat was erupting based on fieldwork done by scientists during 3-7 October. Seismic records showed multiple explosions, and a gas flux measurement of 3,000 metric tons of sulfur dioxide was detected on 3 October. The Alert Level was raised to 2 (on a scale of 0-5).

Source: Vanuatu Geohazards Observatory


30 September-6 October 2009

According to news articles from 2 October, increased seismicity at Gaua was detected during the previous two weeks. Villagers living nearby reported ashfall and sulfur odors. Both villagers and a pilot flying past Gaua heard explosions. The Alert Level was raised to 1 (on a scale of 0-5).

Source: Radio Australia


Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2009 Sep 27 2010 Oct 18 Confirmed 2 Historical Observations Mt. Garat
1982 Apr 18 1982 Apr 18 Confirmed 2 Historical Observations Mt. Garat
1981 Jul 9 1981 Jul 9 Confirmed 1 Historical Observations Mt. Garat
1980 Unknown Confirmed 1 Historical Observations Mt. Garat
1977 Apr 13 1977 Apr 13 Confirmed 2 Historical Observations Mt. Garat
1976 Jan 15 ± 5 days Unknown Confirmed 2 Historical Observations Mt. Garat
1973 Oct 9 1974 Jan 21 Confirmed 2 Historical Observations Mt. Garat (upper SE flank)
1971 May 12 1971 May 13 Confirmed 2 Historical Observations Mt. Garat (upper SE flank)
1969 Sep 22 Unknown Confirmed 2 Historical Observations Mt. Garat
1968 1968 Dec 1 ± 30 days Confirmed 2 Historical Observations Mt. Garat (upper SE flank)
1967 Jul Unknown Confirmed 2 Historical Observations Mt. Garat
1966 Unknown Confirmed 2 Historical Observations Mt. Garat
1965 Sep 27 1965 Sep 30 (in or after) Confirmed 3 Historical Observations Mt. Garat
1963 Sep 15 ± 5 days 1963 Nov 9 (in or after) Confirmed 2 Historical Observations Mt. Garat (upper SE flank)
1962 Jul (in or before) Unknown Confirmed 2 Historical Observations Mt. Garat

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Eissen J-P, Blot C, Louat R, 1991. Chronologie de l'activite volcanique historique de l'arc insulaire des Nouvelles-Hebrides de 1595 a 1991. ORSTOM Rapports Sci Tech Sci Terre Geol-Geophys, 2: 1-69.

Fisher N H, 1957. Melanesia. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 5: 1-105.

Mallick D I J, Ash R P, 1970. Gaua. New Hebrides Geol Surv Ann Rpt 1968, p 27-29.

Mallick D I J, Ash R P, 1975. Geology of the southern Banks Islands. New Hebrides Condominium Geol Surv Reg Rpt, 33 p.

New Hebrides Geological Survey, 1978a. Geology of the Banks Islands. New Hebrides Geol Surv, 1:100,000 geol map sheet 2.

Robin C, Monzier M, Crawford A J, Eggins S M, 1993. The geology, volcanology, petrology-geochemistry, and tectonic evolution of the New Hebrides island arc, Vanuatu. IAVCEI Canberra 1993 excursion guide, Aust Geol Surv Org, Rec 1993/59, 86 p.

The roughly 20-km-diameter Gaua Island, also known as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with an 6 x 9 km wide summit caldera. Small parasitic vents near the caldera rim fed Pleistocene lava flows that reached the coast on several sides of the island; several littoral cones were formed where these lava flows reached the sea. Quiet collapse that formed the roughly 700-m-deep caldera was followed by extensive ash eruptions. Construction of the historically active cone of Mount Garat (Gharat) and other small cinder cones in the SW part of the caldera has left a crescent-shaped caldera lake. The symmetrical, flat-topped Mount Garat cone is topped by three pit craters. The onset of eruptive activity from a vent high on the SE flank of Mount Garat in 1962 ended a long period of dormancy.