Published: 5th December 2016
Activity of the Volcano
The latest eruptive phase of Bromo started in December 2015. The eruptive activity was in the beginning dominated by the ejection of ash and lapili. In late January and February the activity increased and larger explosions were seem, sometimes accompanied by the ejection of lava-bombs/blocks, loud eruption/rumbling sounds and shock-waves. In this period there were also days when strong crater-glow was seen above the crater at night.
The eruptive activity had a short period of rest between the end of February until the end of March. During this period the activity was dominated by degassing but no ash-venting/eruptions.
The Indonesian Volcanology Survey (PVMBG) noted a increase in seismic activity in the first week of April, that was followed by new eruptive activity. Ash-venting and crater-glow was observed. The ash-output was lower than February/March levels. Eruption/rumbling sounds was also present, but lower than January/February levels.
During the second week of April, the activity decreased again and only weak to moderate degassing plumes was observed during until first week of May.
The last week of May the activity increased again, and resumed eruptive activity similar to the activity observed in April.
During June and July the intermittent activity continued, days with only a degassing plume present and periods of low to medium strong ash-venting activity. In the second week of July, ash-fall caused the airport of Malang to close for a few days.
During August the activity was mostly characterized by low to medium levels of degassing. Some degassing-plumes seem to have contained small amounts of ash.
In September the activity have increased, notably by several occasions of ash-venting. According to the The Indonesian Volcanology Survey (PVMBG) the seismic activity have increased in the form of stronger volcanic tremor and more volcanic-earthquakes. Also there might have been inflation at Bromo during the third week of September. These observations led to the PVMBG in raising the status of Bromo from Level 2 to 3 on the 26th September.
Troughout the last week of September and first weeks of October, Bromo again returned to a intermittent state of ash-venting and degassing. The eruptions and Ash-venting was observed to be weak, and the volume of Ash was low, compared to previous Activity earlier in 2016. The Indonesian Volcanology Survey (PVMBG) lowered the alert status of Bromo from Level 3 to Level 2 on Sunday 23th October.
During November I have not seen reports of any ash-emissions from Bromo, and my impression is that the Volcano is in a state of degassing, only emitting a low to medium pressure gas plume.
26th-27th November 2016
Weather conditions was in the area have been poor during November, and during my visit, fog prevented observations most of the time. When observed Bromo was seen emitting a low-pressure gas plume.