Global Volcanism Program

18 July-24 July 2012

CVGHM reported that, although weather conditions at Ijen often prevented views of the volcano during 1-24 July, white plumes were occasionally observed rising 50-100 m above the crater. Seismicity indicated unrest, and along with visual observations, prompted CVGHM to raise the Alert Level to 3 (on a scale of 1-4) on 24 July.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

Available Weekly Reports

18 July 2012 Back to Top

CVGHM reported that, although weather conditions at Ijen often prevented views of the volcano during 1-24 July, white plumes were occasionally observed rising 50-100 m above the crater. Seismicity indicated unrest, and along with visual observations, prompted CVGHM to raise the Alert Level to 3 (on a scale of 1-4) on 24 July.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

9 May 2012 Back to Top

CVGHM reported that during 1-30 April white plumes from Ijen rose 100-200 m above the crater; during 1-11 May diffuse white plumes rose 50-100 m. From the beginning of April until 13 May the amplitude and number of earthquakes gradually decreased and the crater lake water temperature decreased by eight degrees Celsius. The Alert Level was lowered to 2 (on a scale of 1-4) on 13 May.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

21 March 2012 Back to Top

On 24 March, CVGHM reported that Ijen's lake water chemistry changed during 10 January-17 March, exhibiting a significant increase in carbon dioxide, especially after 5 February, and an increase in acidity. The lake surface temperature increased from 28.8 degrees Celsius on 3 March to 45.1 degrees Celsius on 17 March. The lake water temperature at a depth of 5 m also rose from 42.7 to 44.7 degrees Celsius on 3 and 17 March, respectively. Seismicity increased starting in March. The Alert Level remained at 2 (on a scale of 1-4). [Correction: the Alert Level remained at 3.]

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

7 March 2012 Back to Top

CVGHM raised the Alert Level for Ijen from 2 to 3 (on a scale of 1-4) on 12 March because of increased seismicity and visual observations. On 10 March scientists observed some plant damage around the crater lake and a 10-m-wide area of disrupted water on the crater-lake surface.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

8 February 2012 Back to Top

CVGHM lowered the Alert Level for Ijen from 3 to 2 (on a scale of 1-4) on 8 February based on decreased seismicity and visual observations of white plumes rising as high as 300 m above the crater. In addition, a decrease in lake water temperature was measured, which ranged from 42 degrees Celsius on 20 January to 37 degrees on 2 February.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

14 December 2011 Back to Top

CVGHM reported that during 1 October-30 November white plumes from Ijen rose 50-150 m above the crater and lake water temperatures ranged from 26 to 31.6 degrees Celsius. During 1-14 December brownish-white plumes rose 50-200 m above the crater. The lake water temperature was 26.8 and 34.2 degrees Celsius on 8 and 14 December, respectively. Based on increased seismicity, visual observations, and lake water temperature increases, CVGHM raised the Alert Level from 1 to 2 (on a scale of 1-4). During 15-17 December seismicity significantly increased and sulfur dioxide gas emissions around the lake also increased. On 17 December the color of the lake water changed from light green to white. The Alert Level was raised to 3 the next day.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

6 July 2011 Back to Top

The Darwin VAAC reported that on 10 July a pilot observed an ash plume drifting W from Ijen at an altitude of 3.7 km (12,000 ft) a.s.l. [Correction: Later reports from observers indicated that the plume was likely from a nearby forest fire and not from Ijen. Scientists noted that the seismic activity was quiet and that there were no increases in degassing or boiling of the lake.]

Sources: Darwin Volcanic Ash Advisory Centre (VAAC)

15 June 2005 Back to Top

According to the Darwin VAAC, on 17 June a pilot observed a plume from Ijen at a height of ~6.1 km (20,000 ft) a.s.l. Ash was not visible on satellite imagery.

Sources: Darwin Volcanic Ash Advisory Centre (VAAC)

16 June 2004 Back to Top

According to a news article, people were prohibited from visiting Ijen due to an increase in activity beginning on 17 June. The chief of the national park was reported as saying, "There have been sulfuric rocks coming out of the edge of the crater and the fluid in it [crater lake] has turned from green to white and it has emitted hot foam. There are also increasing tremors."

Sources: Reuters

6 February 2002 Back to Top

VSI reported that during 28 January-3 February there was an increase in seismicity at Ijen in comparison to the previous week. In addition to continuous tremor, 2 small explosions were recorded. The volcano remained at Alert Level 2.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

11 July 2001 Back to Top

The Darwin VAAC reported that at 0120 on 15 July sulfur fumes entered the cabin of an aircraft flying from Singapore to Denpasar. At the time, the aircraft was flying at an altitude of ~2.4 km a.s.l. ~15 km SE of Ijen. VSI stated that earlier, during 2-8 July, seismic and explosive activity had increased and the Alert Level had been raised from 1 to 2 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

2 May 2001 Back to Top

During 23-29 April seismic activity was higher than normal at Ijen, with a high number of shallow volcanic earthquakes (nine). In addition, one small explosion event and seven tectonic earthquakes were recorded. Visual observations were not possible. The volcano remained at Alert Level 2 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

25 April 2001 Back to Top

During 16-23 April there was an increase in the number of shallow volcanic earthquakes (ten) in comparison to the previous week. Seismographs also recorded one deep volcanic, and two tectonic earthquakes. The volcano remained at Alert Level 2 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

18 April 2001 Back to Top

Volcanic activity at Ijen during 9-15 April was higher than normal, with a relatively large number (nine) of shallow volcanic earthquakes. Seismographs also recorded ten small explosion events. The volcano remained at Alert Level 2 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

11 April 2001 Back to Top

Seismic activity at Ijen was high during 2-9 April. Five episodes of tremor were reported. The number of shallow volcanic earthquakes decreased in comparison to the previous week. Overall, seismographs recorded 13 shallow volcanic earthquakes, two tectonic earthquakes, and one small explosion event. The volcano is at Alert Level 2 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

4 April 2001 Back to Top

During 27 March- 1 April, seismic activity at Ijen increased in comparison to the previous week. Seismographs on the volcano detected 35 shallow volcanic earthquakes, seven tectonic earthquakes, and one small explosion. The volcano remained at Alert Level 2 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

28 February 2001 Back to Top

During 20-26 February, the number of earthquakes recorded was relatively high; 42 shallow volcanic earthquakes and five tectonic earthquakes were detected. The volcano remained at Alert Level 2 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

7 February 2001 Back to Top

During 30 January to 5 February, seismic activity increased at Ijen volcano. This increase was marked by a large number of shallow volcanic earthquakes (75). In addition, 2 small explosion events, 6 tectonic events, and 2 tremor earthquakes occurred. The volcano is at Alert Level 2 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

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

Start Date	Stop Date	Eruption Certainty	VEI	Evidence	Activity Area or Unit
[ 2002 Jul 29 ]	[ 2002 Aug 15 ± 3 days ]	Uncertain	1		Kawah Ijen
[ 2000 Sep 1 ± 5 days ]	[ 2000 Sep 10 ± 3 days ]	Uncertain	1		Kawah Ijen
1999 Jun 28	1999 Jun 28	Confirmed	1	Historical	Kawah Ijen
1994 Feb 3	1994 Feb 3	Confirmed	1	Historical	Kawah Ijen
1993 Jul 3	1993 Aug 1	Confirmed	1	Historical	Kawah Ijen
1952 Apr 22	1952 Apr 24 ± 1 days	Confirmed	1	Historical	Kawah Ijen
1936 Nov 5	1936 Nov 25	Confirmed	2	Historical	Kawah Ijen
1917 Feb 25	1917 Mar 14	Confirmed	1	Historical	Kawah Ijen
1817 Jan 15	1817 Feb 18 (?)	Confirmed	1	Historical	Kawah Ijen
1796	Unknown	Confirmed	2	Historical	Kawah Ijen
640 BCE ± 50 years	Unknown	Confirmed		Radiocarbon (uncorrected)	Kawah Ijen

The Ijen volcano complex at the eastern end of Java consists of a group of small stratovolcanoes constructed within the large 20-km-wide Ijen (Kendeng) caldera. The north caldera wall forms a prominent arcuate ridge, but elsewhere the caldera rim is buried by post-caldera volcanoes, including Gunung Merapi stratovolcano, which forms the 2799 m high point of the Ijen complex. Immediately west of Gunung Merapi is the renowned historically active Kawah Ijen volcano, which contains a nearly 1-km-wide, turquoise-colored, acid crater lake. Picturesque Kawah Ijen is the world's largest highly acidic lake and is the site of a labor-intensive sulfur mining operation in which sulfur-laden baskets are hand-carried from the crater floor. Many other post-caldera cones and craters are located within the caldera or along its rim. The largest concentration of post-caldera cones forms an E-W-trending zone across the southern side of the caldera. Coffee plantations cover much of the Ijen caldera floor, and tourists are drawn to its waterfalls, hot springs, and dramatic volcanic scenery.