Logo link to homepage

Report on Concepcion (Nicaragua) — 20 August-26 August 2003

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 August-26 August 2003
Managing Editor: Gari Mayberry

Please cite this report as:

Global Volcanism Program, 2003. Report on Concepcion (Nicaragua). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 20 August-26 August 2003. Smithsonian Institution and US Geological Survey.

Volcano Profile |  Weekly Report (20 August-26 August 2003)


Concepcion

Nicaragua

11.538°N, 85.622°W; summit elev. 1700 m

All times are local (unless otherwise noted)


According to news articles, INETER reported increased seismicity at Concepción on 21 August. People on the island of Ometepe did not feel the tremor, which ended on 22 August.

Geologic Background. Volcán Concepción is one of Nicaragua's highest and most active volcanoes. The symmetrical basaltic-to-dacitic stratovolcano forms the NW half of the dumbbell-shaped island of Ometepe in Lake Nicaragua and is connected to neighboring Madera volcano by a narrow isthmus. A steep-walled summit crater is 250 m deep and has a higher western rim. N-S-trending fractures on the flanks have produced chains of spatter cones, cinder cones, lava domes, and maars located on the NW, NE, SE, and southern sides extending in some cases down to Lake Nicaragua. Concepción was constructed above a basement of lake sediments, and the modern cone grew above a largely buried caldera, a small remnant of which forms a break in slope about halfway up the N flank. Frequent explosive eruptions during the past half century have increased the height of the summit significantly above that shown on current topographic maps and have kept the upper part of the volcano unvegetated.

Sources: La Prensa (Nicaragua), El Nuevo Diario