Explosion at Masaya Volcano, Nicaragua

By Wilfried Strauch

Yesterday, April 23, 2001, at 02:26 PM local time (8:26 UT), an explosion occurred in the crater Santiago of Masaya volcano. This explosion formed a new vent in the bottom of Santiago. The explosion first launched rocks with diameters up to 60 cm which impacted at distances up to 500 m from the crater.

Vehicles parked at the visitors platform were damaged and one person was injured. In the moment of the explosion about 200 persons were present at or near the visitors platform. In a second and third phase of the explosion small quantities of lava and volcanic ash were expulsed which caused bush fires near the crater rim. The seismic recording at the seismic station installed near the crater shows that the explosion lasted about 2 minutes.

Degassing continued stronger than in the last weeks and months. Episodic ash fall was reported near Ticuantepe, Northwest of Masaya volcano and people were affected by high concentrations of volcanic gases. INETER volcanologists who continuously monitored Santiago in the afternoon and during the night reported several smaller explosions, gas outbreaks and minor collapses of the crater wall.

Scientists from Cambridge University/UK who carried out gas measurements at Santiago crater and left just one hour before the explosion had not noticed any unusual behavior of the volcano before the event. Also, the seismic recordings, according to preliminary inspection, does not indicate unusual activity.

The authorities of the National Park of Masaya Volcan closed public access to the visitors platform for the next days.

The official report of INETER, additional information and photos can be found in our Web page http://www.ineter.gob.ni/geofisica/vol/masaya/masaya.html