Report on San Cristobal (Nicaragua) — 19 December-25 December 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 19 December-25 December 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on San Cristobal (Nicaragua). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 19 December-25 December 2012. Smithsonian Institution and US Geological Survey.
12.702°N, 87.004°W; summit elev. 1745 m
All times are local (unless otherwise noted)
INETER reported that on 25 December at 1800 seismicity at San Cristóbal increased. A series of explosions starting at 2000 produced ash-and-gas plumes that rose 500 m above the crater and drifted SW and likely W. Ash fell near the volcano. Seismicity increased significantly the next day. Explosions continued to generate ash-and-gas plumes that rose 2.5 km above the crater and drifted N, W, and SW as far as the Pacific Ocean (30-40 km SW and W, respectively). Ashfall was reported in areas downwind, including Puerto Morazan, Jiquilillo, Aposentillo, Tonalá, El Viejo, Santa Marta, and the cities of Chinandega, Chichigalpa, Corinth, and Realejo. According to news articles, some families near the volcano self-evacuated.
Geologic Background. 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.