VONA
What is VONA?

VONA stands for Volcano Observatory Notice for Aviation. It issues reports for changes, both increases and decreases, in volcanic activities, providing a description on the nature of the unrest or eruption, potential or current hazards as well as likely outcomes. See the following link (USGS) for further details. The Center for Volcanology and Geological Hazard Mitigation (CVGHM) under the Geological Agency of the Indonesian Ministry of Energy and Mineral Resources produced VONA's reports based on analysis of data from the agency's monitoring networks as well as from direct observations. VONA's alert levels are color-coded to indicate the different types of notifications addressing specific informative needs. The reports are disseminated via email to national and international stakeholders in the aviation sector. Other interested parties can avail of them through email subscription. All notifications are publicly available online.

USGS
 

5th of July 2018, 3 years ago

2018-07-05 09:59:00 UTC Orange

Anak Krakatau - 20180705/0959Z 

Deny Mardiono, A.Md., Anak Krakatau Volcano Observatory - 3 years ago

Eruption with ash clouds at 09:51 UTC (16:51 local time). The eruption lasted for 30 seconds. Eruption and ash emission is continuing. Best estimate of ash-cloud top is around 6389 FT (1936 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud is moving to northwest.

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2018-07-05 07:29:00 UTC Orange

Anak Krakatau - 20180705/0729Z 

Deny Mardiono, A.Md., Anak Krakatau Volcano Observatory - 3 years ago

Eruption with ash clouds at 07:25 UTC (14:25 local time). The eruption lasted for 33 seconds. Eruption and ash emission is continuing. Best estimate of ash-cloud top is around 6389 FT (1936 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud is moving to north.

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2018-07-05 07:16:00 UTC Orange

Anak Krakatau - 20180705/0716Z 

Deny Mardiono, A.Md., Anak Krakatau Volcano Observatory - 3 years ago

Eruption with ash clouds at 07:09 UTC (14:09 local time). The eruption lasted for 41seconds. Eruption and ash emission is continuing. Best estimate of ash-cloud top is around 8501 FT (2576 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud is moving to north.

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4th of July 2018, 3 years ago

2018-07-04 01:33:00 UTC Orange

Anak Krakatau - 20180704/0133Z 

Deny Mardiono, A.Md., Anak Krakatau Volcano Observatory - 3 years ago

Eruption with ash clouds at 22:33 UTC (05:33 local time). The eruption lasted for 40 seconds. Eruption and ash emission is continuing. Best estimate of ash-cloud top is around 0 FT (0 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud is moving to North. Anak Krakatau volcano is not clear and not visible..

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3rd of July 2018, 3 years ago

2018-07-03 23:39:00 UTC Orange

Anak Krakatau - 20180703/2339Z 

Deny Mardiono, A.Md., Anak Krakatau Volcano Observatory - 3 years ago

Eruption with ash clouds at 22:33 UTC (05:33 local time). The eruption lasted for 40 seconds. Eruption and ash emission is continuing. Best estimate of ash-cloud top is around 0 FT (0 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud is moving to North. Anak Krakatau volcano is not clear and not visible..

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2018-07-03 23:33:00 UTC Orange

Anak Krakatau - 20180703/2333Z 

Deny Mardiono, A.Md., Anak Krakatau Volcano Observatory - 3 years ago

Eruption with ash clouds at 22:33 UTC (05:33 local time). The eruption lasted for 40 seconds. Eruption and ash emission is continuing. Best estimate of ash-cloud top is around 0 FT (0 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud is moving to North. Anak Krakatau volcano is not clear and not visible..

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2018-07-03 12:03:00 UTC Orange

Anak Krakatau - 20180703/1203Z 

Deny Mardiono, A.Md., Anak Krakatau Volcano Observatory - 3 years ago

Eruption at 11:21 UTC (18:21 local time). Eruption and ash emission is continuing Best estimate of ash-cloud top is around 0 FT (0 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud is moving to North. Anak Krakatau volcano is not clear and not visible..

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25th of June 2018, 3 years ago

2018-06-25 08:13:00 UTC Orange

Anak Krakatau - 20180625/0813Z 

Martanto, S.T., Anak Krakatau Volcano Observatory - 3 years ago

Eruption with volcanic ash cloud at 0742 UTC (1442 local) Best estimate of ash-cloud top is around 6389 FT (1936 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud moving to South. .

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2018-06-25 01:00:00 UTC Orange

Anak Krakatau - 20180625/0100Z 

Martanto, S.T., Anak Krakatau Volcano Observatory - 3 years ago

Eruption with volcanic ash cloud at 0014 UTC (0714 local) Best estimate of ash-cloud top is around 13781 FT (4176 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud moving to North..

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19th of February 2017, 4 years ago

2017-02-19 12:47:00 UTC Orange

Anak Krakatau - 20170219/1247Z 

Hetty Triastuty, Dr. S.Si, M.Sc, Anak Krakatau Volcano Observatory - 4 years ago

Strombolian eruption occurred at 1204 UTC (1904 local time). Incandescent ejected material reached 200 m in high. Best estimate of ash-cloud top is around 0 FT (0 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. No ash-cloud observed.

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20th of June 2016, 5 years ago

2016-06-20 04:49:00 UTC Yellow

Anak Krakatau - 20160620/0449Z 

Martanto, S.T., Anak Krakatau Volcano Observatory - 5 years ago

Seismograph at Anak Krakatau Volcano Observatory detected an eruption occurred at 05:51 Local Time or 22:51 UTC, but the eruption was not observed visually from the observatory because of cloudy weather. The seismicity increased before the eruption, preceded by a swarm of volcanic earthquakes about 1 day before and significantly increased 3 hours before the eruption. After the eruption, seismic activity decreases gradually. Best estimate of ash-cloud top is around 0 FT (0 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. -.

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VONA Color Code

Volcano is in normal, non-eruptive state, or, after a change from a higher level: Volcanic activity considered to have ceased, and volcano reverted to its normal, non-eruptive state.


Volcano is experiencing signs of elevated unrest above known background levels, or, after a change from higher level: Volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.


Volcano is exhibiting heightened unrest with increased likelihood of eruption with column height below 6000 meter above sea level.


Eruption is forecast to be imminent with significant emission of ash with column height above 6000 meter above sea level.