Abstract

 

The monitoring and early warning system was maintained around the clock during all the year. This system guaranteed the rapid and correct information of the authorities and the general public about the seismic and volcanic activity and other important geologic phenomena in Nicaragua.

 

Seismicity

- During 2005, the seismic network registered 2,785 seismic events, most of them associated with the subduction zone and the volcanic chain of Nicaragua.  2,629 events were located and at least 78 events were felt by the population.

- On August 3, the most important seismic event occurred with a magnitude ML= 5.7 (NEIC: 6.2 Ms). It was located at the South of Maderas volcano in Lake Nicaragua. It caused destruction of some houses at Ometepe Island and was felt allover Western Nicaragua and also in the North of Costa Rica.

- Another strong seismic event occurred on July 01 with epicenter in the Pacific Ocean, off the coast of El Astillero. It had a  magnitude of ML=6.2 and was felt allover the Pacific region of Nicaragua..

 

Volcanoes

- The surveillance of the active volcanoes continued by means of seismic monitoring, visual observations, temperatures measurements, Web cameras and meteorological monitoring. During 83 visits made over the year  to the active craters, fumaroles and other places in the volcanoes INETER obtained numerous measurements of temperature, gas samples andvaluable  visual observations.

From the end of July to November 2005, Concepcion volcano maintained a low level volcanic activity with small phreatic explosions. In the months of November and December, San Cristobal volcano showed some minor  volcanic activity with small explosions of ashes but occasional strong gas emanations. Telica presented low activity with little gas emission. During the month of December 2005, Masaya volcano presented small explosions of ashes and maintained the gas emission in large amounts.  Cerro Negro volcano stayed calm during the year.

 

Landslides

- On May 18, 2005, a lahar occurred at the Northern flanks of Concepcion volcano, minor effects for  the communities of La Florr and San José de el Norty.

- June 29, occurred another lahars in the North of Concepcion volcano, near the communities of La Concepcion and La Flor.

- In the last week of September, 2005, landslides occurred  at Casita volcano affecting Buena Vista and Santa Cruz.

- In October,  2005, a small landslide occurred at  Coyotepe, Masaya.

- In October, 2005, occurred a mud  flow in the Lagoon of Apoyo.

 

Project work

The following projects were executed at Geophysical Department:

 - Mitigation of Geo-Risks in Nicaragua and Central America (with BGR-Germany, Development of the GIS of  Geo-Risks).

- Topographical Maps and Maps for a GIS on Seismic, Volcanic, Hydrologic and Tsunami hazards in Nicaragua (JICA- Japan).

- Studies of the Geological Hazards and recognition of materials for construction in the Municipalities of Ocotal and Dipilto..

- Consolidation of the Networks of Surveillance of Natural Phenomena).

- Volcanic Surveillance with Satellite Images (King´s College, UK).

- Subduction Processes, Natural Disasters and Climate (GEOMAR, Germany). 

- Temporary Seismic Broad Band Network (Boston University, USA). .

- Early Warning System for Cerro Negro Volcano. (CARE/EU-SINAPRED, Civil Defense, Mayor's offices of León, Telica and Malpaisillo).

- Geological and Hydrological Hazards at Sites foreseen for Rural Urbanization (INVUR-BID)..

- Seismic Vulnerability of Managua city (World Bank, SINAPRED).

- Hazard Maps of the Municipality of Rio Blanco (COSUDE-INETER-Technical Cooperation of Netherlands and Mayor's office of Rio Blanco).

-  Design of the Regional Tsunami Warning System (CEPREDENAC, COSUDE).

- Early Warning system for Landslides at El Volcán, near Dipilto (part of project “Strengthening the Local Capacities for the Prevention, Mitigation and Attention to Disasters in the Municipality of Dipilto”) (FOLCAPRED-ACSUR/EU).

 

Development of the monitoring and early warning system for dangerous geologic phenomena

- A seismic array was with 6 sensors was installed at  INETER´s premises in Managua

- In August two Web cameras was installed for the visual monitoring of Concepcion volcano.