Strong explosion at Momotombo volcano, Nicaragua

After 110 years of being dormant, Momotombo volcano, Nicaragua, seems to have become fairly active over the last two months. The latest eruption occurred on January 12, 2016 (local time), Volcano Discovery reported.

A strong explosion at 12:10 (local time) sent an ash plume about 3 km (9 842.5 feet) from the volcano summit and generated a small pyroclastic flow.

Momotombo eruption recorded on January 12, 2016. Image credit: INETER

Momotombo volcano awakened on the morning of December 1, 2015. Four eruptions were recorded on the occasion sending steam and ash plumes up to 1 km (3 281 feet) above the volcano summit.

In the period between December 2 and 3, ash plumes from the volcano rose to 2.4 km (8 000 feet) in the air and drifted between 90 and 225 km (55.9 and 139.8 miles) NW and WNW, according to the Washington VAAC, based on satellite and webcam observations.

Momotombo eruption on December 2, 2015. Image credit: Canal6Nicaragua

INETER and SINAPRED reported activity at Momotombo continued through December 10. Conducted fieldwork showed a small, incandescent, circular crater halfway up Momotombo's eastern flank that was fuming on the morning of December 6. On December 7, an explosion occurred and destroyed part of the crater. SINAPRED reported the material had been accumulating in the crater since the eruption began. Between December 9 and 14, seismicity was low and stable.

No further explosions were reported during December 29 and 30, according to INETER, although Real-time Seismic-Amplitude Measurements (RSAM) showed moderate to high levels activity. Three gas and ash explosions were reported on January 2, at 13:33, 14:26 and 14:34 local time. They excavated the remaining parts of the lava dome emplaced a month before that.

Video credit: La Prensa

An ash plume rose 500 m (1 640.4 feet) above the crater, drifted S and SW and caused ashfall in Puerto Momotombo, 9 km (5.6 miles) away, Global Volcanism Program (GVP) reported. Possible ash plumes from an explosion at 21:29 were hidden by the darkness. On January 3, 2016, at 04:20, an explosion ejected lava bombs 2 km (6 561.7 feet) away and caused ashfall in La Paz Centro, 18 km (11.2 miles) SW. Lava flows had advanced as far as 2 km (6561.7 feet) down the NE flank.

December 2015 is the first time the volcano showed the signs of eruptive activity since 1905, and only 16 eruptions have been recorded since 1524, most of which have been small explosions of phreatic nature. The only two larger eruptions were observed in 1605 and 1609 when large bombs and blocks were expelled to the distances of approximately 6 km (19 685 feet), in the area of the nowadays abandoned town of León Viejo.

The explosion reported on January 3 ignited the vegetation on the flanks of Momotomba volcano.

Geological summary

Momotombo is a young, 1 297-m-high (4 255 feet) 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 (492 x 820 feet) wide summit crater. Young lava flows from Momotombo have flowed down the NW flank into the 4-km-wide (2.5 miles) Monte Galán caldera.

The youthful cone of Momotombito forms a 391-m-high (1 282.8 feet) island offshore in Lake Managua. Momotombo has a long record of strombolian eruptions, punctuated by occasional larger 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 an April 10, 1996, earthquake, but later observations noted no significant changes in the crater. A major geothermal field is located on the southern flank of the volcano. (GVP)

Featured image: Momotombo eruption recorded on January 12, 2016. Image credit: INETER