During 2-3 March INETER reported that 53 small explosions at Momotombo generated low-energy gas plumes that rose 300 m above the crater. On 3 March some of the explosions produced ash plumes that drifted W and SW. RSAM values were at low to moderate levels. SINAPRED reported that during 5-6 March there were 78 explosions for a total of 279 explosions detected since 1 December 2015. One of the most significant explosions occurred on 6 March. The next day gas-and-ash plumes rose as high as 1 km above the crater.

Geological Summary. Momotombo is a young stratovolcano that rises prominently above the NW shore of Lake Managua, forming one of Nicaragua's most familiar landmarks. Momotombo began growing about 4500 years ago at the SE end of the Marrabios Range and consists of a somma from an older edifice that is surmounted by a symmetrical younger cone with a 150 x 250 m wide summit crater. Young lava flows extend down the NW flank into the 4-km-wide Monte Galán caldera. The youthful cone of Momotombito forms an island offshore in Lake Managua. Momotombo has a long record of Strombolian eruptions, punctuated by occasional stronger explosive activity. The latest eruption, in 1905, produced a lava flow that traveled from the summit to the lower NE base. A small black plume was seen above the crater after a 10 April 1996 earthquake, but later observations noted no significant changes in the crater. A major geothermal field is located on the south flank.

Sources: Instituto Nicaragüense de Estudios Territoriales (INETER), Sistema Nacional para la Prevención, Mitigación y Atención de Desastres (SINAPRED)