Introduction

The Instituto Nicaragüense de Estudios Territoriales (INETER) presents this Annual Catalogue, "Sismos and Volcanes de Nicaragua, 2005" with the purpose to inform in a summarized form on the seismic, volcanic, and geologic phenomena in Nicaragua, the  development of the surveillance networks and on the progress of the projects of investigation and development. The content of this catalog is based on the monthly bulletins that the Department of Geophysics publishes regularly.

 

The Geophysical Department of INETER has the principal responsibility to monitoring and early warning the seismic, volcanic and geologic phenomena in Nicaragua, operates networks of seismic and geophysical stations and performs the volcanic surveillance. It also carries out scientific studies on the dangerous geologic processes in Nicaragua and develops a Geographical Information System (GIS) on these phenomena. The Department of Geophysics is divided in 1) Seismology Section (includes Laboratory of Electronics), 2) Volcanology Section, 3) Section on Geology Applied to Geohazards, 4) GIS Unit on Geo-Risks.

 

The most important geologic event in 2005, was the earthquake which occurred, on August 3, beneath Lake Nicaragua. It caused the destruction of several houses on Ometepe Island, with a magnitude 5.7 ML comparable with the 1972 Managua earthquake. It was actually the strongest seismic event occurring on land in Nicaragua after the Managua earthquake.

 

Other important events reported in this catalog,  are the volcanic explosions which occurred from July to November at Concepcion volcano, lahars at Concepcion volcano in May, several small explosions in the volcano San Cristobal in November and December, a strong seismic event occurring in August in the Pacific Ocean in front off El Astillero, and small explosions at Masaya volcano which occurred in December.

 

There is included information on other seismic events, earthquakes, seismicity in form of seismic swarms occurring on inhabited areas and events felt by the population mainly in the Pacific Region.

 

The seismic and volcanic surveillance of the Nicaraguan active volcanoes was guaranteed during he year. 83 field visits ware made to the active craters, fumaroles and other sites. The surveillance was intensified at Concepcion volcano with Web cameras.

 

During 2005, Geophysical Department revised reports submitted by private geologists and emitted 92 guarantees on their work. Geologic studies in Managua and other regions of the country, are required for the local regulations in order to obtain the permission of construction.

 

In 2005, the Geophysical Department worked intensely in 13 investigation and development projects, the activities and results of which are summarized shortly in this catalogue.

 

Many projects produce geographic coverage of geologic hazard, vulnerability and risk were integrated in the GIS of Geo-Risks which is an important tool for the basic investigation and the information to the public about disaster prevention in Nicaragua.