It reduced his volcanic activity, significantly reducing the output of gases, ash and lava. Seismic amplitude values ??in real time (RSAM) are kept low and stable, but the eruptive activity of the Momotombo is not over yet , so that new explosions can occur at any time, even with expulsion of lava.
Formation of a volcanic dyke and a lava dome:
The specialists of the Nicaraguan Institute of Territorial Studies (INETER) conducted field studies during which they identified that the lava ejected during the first three days of this eruptive phase (between 1 and 4 December) has formed a lava dome on the volcano‘s crater floor, completely covering the crater.
This lava is rich in silica and therefore viscous and produces a bulbous mass called dome. This phenomenon is being studied to determine if the dome is growing.
« We want to explain that the dome is caused by the slow eruption of lava, this does not allow the lava to flow away from the crater, which is why the lava becomes solid on the volcano. The domes can develop over time and take more and more height. The concentration of gases and temperatures may cause the explosion of the dome and eject pyroclastic material, in a stronger eruptions « .
« It should be noted that at 1:50 p.m. local time (7:50 p.m. GMT) on Monday, it was an explosion that destroyed the southern part of the lava dome,« experts said.
During field studies, it was found that on December 6 in the morning, was formed a circular aperture of a few meters in diameter halfway up the eastern flank of the volcano, because of a rise of a cylindrical magmatic body known as « volcanic dyke » that broke the volcano wall without going out. It was observed through this aperture the output of volcanic gases and incandescent materials, which indicates that it is possible that if the lava emission is reactivated, the dam may be expelled on the flanks of the volcano facilitating the flow of lava over a greater distance.
Explosions could blow the material accumulated in the dome and in addition to other explosions and lava emissions may occur. So the same level of risk remains and it is recommended not to approach the base of the volcano.
December 11, 2015. Momotombo, Nicaragua :
Source : Ineter / Avcan
Photos : La Prensa ,