INETER stated that during the evening of 12 November small ash emissions took place at San Cristóbal. The emissions produced ash clouds that remained around summit level. According to the Washington VAAC, on 12 November at 1645 GOES-8 imagery showed a small area of possible ash drifting NW. According to ground observations, moderate volcanic activity occurred until 1800. Ash had dissipated by 2100 and the next day there were no ground reports of volcanic activity.

Geological Summary. The San Cristóbal volcanic complex, consisting of five principal volcanic edifices, forms the NW end of the Marrabios Range. The symmetrical 1745-m-high youngest cone, named San Cristóbal (also known as El Viejo), is Nicaragua's highest volcano and is capped by a 500 x 600 m wide crater. El Chonco, with several flank lava domes, is located 4 km W of San Cristóbal; it and the eroded Moyotepe volcano, 4 km NE of San Cristóbal, are of Pleistocene age. Volcán Casita, containing an elongated summit crater, lies immediately east of San Cristóbal and was the site of a catastrophic landslide and lahar in 1998. The Plio-Pleistocene La Pelona caldera is located at the eastern end of the complex. Historical eruptions from San Cristóbal, consisting of small-to-moderate explosive activity, have been reported since the 16th century. Some other 16th-century eruptions attributed to Casita volcano are uncertain and may pertain to other Marrabios Range volcanoes.

Sources: Washington Volcanic Ash Advisory Center (VAAC), Instituto Nicaragüense de Estudios Territoriales (INETER)