During the period from 18 to 25 February 2016 it was recorded six earthquakes, earthquakes of eruptions and continuous tremors with maximum amplitude ranges from 1 to 24 mm. From the date of February 22, 2016, the seismic tremor was recorded continuously with a maximum magnitude of 0.5 to 2 mm, earthquakes eruption were not recorded.
The deformation monitoring of G. Bromo is done using the method EDM (electronic distance measurement) and inclinometers. The EDM method that consists of three monitoring points and permanent checkpoints, G. Kursi, Bromo and Mount Batok, this measure has often been hampered by the fog around Mount Bromo.
The tilt and EDM measures within a period of 2 to 26 February 2016 using a new measuring point and EDM, the measurement results of the February 10 until February 25, 2016 show that deformation varies with a stable trend.
The visual activity of G. Bromo is often shrouded in fog. An emission of thick white smoke gray with a high column of 50 to 900 meters high with a change in direction between the North-East and West-Southwest is present, the roar over the last five days were not present.
The recording of the seismicity is dominated by a constant tremor with a maximum amplitude which fluctuated in the range of 1 to 30 mm and on February 22, 2016, the maximum tremor dominant amplitude was 0.5 to 2 mm . Earthquakes eruption were not recorded again.
Measurements of deformation with tilt and EDM shows fluctuations and a stable trend.
The occurrence of an eruption is suddenly possible, with the emission of volcanic material as ash and stones jets around the crater and into a radius of 1 km from the eruption center.
Seismic activity is dominated by continuous tremor vibration with an amplitude in decrease, earthquakes of eruptions were not recorded again.
The threat of an eruption in the form of emission of ash and jets of material could produce up to a radius of 1 km.
Based on observational data and analysis of seismic data, visual, and the potential danger of eruption, the activity level of G. Bromo goes from the Level III (SIAGA) to level II (Waspada) on 26 February 2016.
The activity level of Bromo will be raised / lowered if an increase / decrease of the activity is recorded extensively by experts of the Centre for volcanic risk mitigation, volcanology and geology.
February 27 , 2016. Bromo, Indonesia :
Source : VSI
Photos : Oystein Lund Andersen ( archives), G Vitton.