INETER reported that on 23 May around dawn a vapor column was observed rising above San Cristóbal. The plume was attributed to rain contacting hot material in the crater. There was no indication of an increase in volcanism at San Cristóbal. According to the Washington VAAC, the plume rose ~3 km a.s.l. and drifted to the SW. For the previous few months seismicity had been at moderate levels.

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)