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
14th of May 2017, 2 years ago
There is an increasing volcanic activity. Visual observation does not show any sign of eruption. 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. Visual observation does not show any sign of eruption..View
29th of September 2016, 3 years ago
Lokon Volcano Observatory has detected an increase in volcanic activity at Lokon Volcano, Tomohon, North Sulawesi province. This increase is observed in the past 24 hours. Therefore, the Aviation Color Code is set to YELLOW. There is no indication that an eruption is imminent or certain, however the potential for an eruption is increased. Lokon 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.View
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.