INETER reported that a series of five low- to medium-intensity explosions were recorded at San Cristóbal between 0522-0526 on 15 December. Ash plumes rose 2.5 km above the crater rim and drifted W, causing ashfall in La Grecia, Rancherías (8 km NW), and El Viejo (18 km SW). Rocks were ejected 500 m from the vent onto the flanks.

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.

Source: Instituto Nicaragüense de Estudios Territoriales (INETER)