Report on San Cristobal (Nicaragua) — 16 November-22 November 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 November-22 November 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on San Cristobal (Nicaragua). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 16 November-22 November 2005. Smithsonian Institution and US Geological Survey.
12.702°N, 87.004°W; summit elev. 1745 m
All times are local (unless otherwise noted)
There was an increase in seismicity at San Cristóbal beginning on 19 November. Increased tremor was interpreted as being related to gas and ash emissions. Ash fell W of the volcano and near the town of Chinandega, ~15 km SW of the volcano. The amount of tremor decreased later.
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.