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.
USGS20th of June 2016, 5 years ago
Anak Krakatau - 20160620/0449Z
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. -.
View3rd of June 2016, 5 years ago
Eruption with volcanic ash cloud at 0135 UTC (0835 local) Best estimate of ash-cloud top is around 83424 FT (25280 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Brown-grey ash-cloud moving to east-northeast..
View29th of May 2016, 5 years ago
Eruption with volcanic ash clouds at 06:30 UTC (13:30 local time). The eruption lasted for 257 seconds. Best estimate of ash-cloud top is around 104333 FT (31616 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash clouds is moving to east.
View24th of May 2016, 5 years ago
Eruption happened in 24/05/2016 06:17 WIB with brown ash, and presure low, cloud height about 900 meters above summit, and move to the east Best estimate of ash-cloud top is around 34099 FT (10333 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. ash cloud move to the east with low presure.
View4th of May 2016, 6 years ago
Eruption with volcanic ashclouds at 0943 localtime or 0243 UTC Best estimate of ash-cloud top is around 48576 FT (14720 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash-cloud top is around 4600 meter above sea level, Ash-cloud moving west. Source of height data: ground observer..
View2nd of May 2016, 6 years ago
Eruption with grey-colored ash is observed. The eruption and ash emission is continuing. Best estimate of ash-cloud top is around 19925 FT (6038 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. The volcanic ash is moving towards west direction..
View1st of May 2016, 6 years ago
Gamalama Volcano Observatory has detected a slight increase in volcanic tremor activity at Gamalama Volcano on Ternate Island in the North Maluku province. This increase is observed at least since 1 May 2016 00:30 UTC (09:30 local time). The recorded tremor amplitudes vary around 0.5-4.0 mm while the background is around 0.5-1.00mm. Therefore, the Aviation Color Code is set to YELLOW. There is no indication that an eruption is imminent or certain, although the potential for an eruption has increased. Gamalama Volcano Observatory will continue to monitor the volcano closely. 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. NILL.
View24th of April 2016, 6 years ago
Eruption with white-grey colored volcanic ash-cloud is observed on 24 April 2016 at 22:45 UTC (25 April 2016 at 07:45 UTC). Eruption is continuing. Best estimate of ash-cloud top is around 20981 FT (6358 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash-cloud is moving to Southeast..
View23rd of April 2016, 6 years ago
Eruption with white-grey colored ash is clearly observed at 12:32 UTC. Eruption is still ongoing. Best estimate of ash-cloud top is around 21509 FT (6518 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash-cloud moving to East..
View14th of April 2016, 6 years ago
Continuous eruption with volcanic ash cloud is observed on 14 April 2016 at 21:57 UTC (15 April 2016 06:57 localtime/UTC +9). Eruption and ash emission is continuing. Best estimate of ash-cloud top is around 18341 FT (5558 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Grey coloured ash-cloud is moving to the west-southwest..
View10th of April 2016, 6 years ago
Continuous eruption with white-grey coloured volcanic ash cloud is observed on 10 April 2016 at 05:58 UTC (14:58 local/UTC 9). Eruption and ash emission is continuing. Best estimate of ash-cloud top is around 22037 FT (6678 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash-cloud is moving to the northeast..
View3rd of April 2016, 6 years ago
Eruption with vulcanic ash above 600m from the summit or 2929m above sea level Best estimate of ash-cloud top is around 30931 FT (9373 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud white greay to brown move to south west and still continue.
ViewEruption with vulcanic ash above 600m from the summit or 2929m above sea level Best estimate of ash-cloud top is around 30931 FT (9373 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud white greay to brown move to south west and still continue.
ViewEruption with vulconic ash above 600M from summit or 2929m above sea level and the ash still contuinue Best estimate of ash-cloud top is around 30931 FT (9373 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. Ash cloud grey white to brown move south west.
View2nd of April 2016, 6 years ago
High steam emissions (with sometimes contains ash material, although not everday) Best estimate of ash-cloud top is around 34099 FT (10333 M) above sea level, may be higher than what can be observed clearly. Source of height data: ground observer. high steam emissions with sometimes contains ash material, although not everday..
ViewVolcano 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.
