INETER reported moderate levels of gas emissions at Momotombo on 10 February; volcanic tremor and gas emissions increased to moderate-to-high levels the next day. An explosion on 12 February produced small ash emissions and ejected incandescent material onto the N and SE flanks. An explosion at 1305 on 15 February generated an ash plume that rose 2 km above the crater and ejected incandescent tephra onto the N and NE flanks.

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.

Source: Instituto Nicaragüense de Estudios Territoriales (INETER)