Report on San Cristobal (Nicaragua) — 6 March-12 March 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 6 March-12 March 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on San Cristobal (Nicaragua). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 6 March-12 March 2002. Smithsonian Institution and US Geological Survey.
12.702°N, 87.004°W; summit elev. 1745 m
All times are local (unless otherwise noted)
Seismic tremor increased at San Cristóbal beginning on the afternoon of 6 March. Strong seismicity occurred in 2- to 3-hour periods that were generally separated by less than 1 hour of less intense activity. Scientists visiting the volcano found that the amount of degassing had increased and that temperatures at the volcano were much higher than they had been for several months. Reportedly, incandescent material in the crater was reflected on the clouds above it. According to INETER, the activity at San Cristóbal was not strong enough to warrant raising the Alert Level.
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.