Clusters of long-period (LP) seismic events recorded during 34 days at the Irazú volcano: What are they telling us?

VILLEGAS A., RAQUEL J.; CARNIEL, ROBERTO; PETRINOVIC, IVAN A.; BALBIS, CATALINA

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2022

0895-9811

This work analyses seismic signals at the Irazú volcano (83°51′09″ W, 9°58′45″ N; active stratovolcano in Central America) in a continuous 34-day record beginning April 13, 2013. Since December 2012, the activity of the volcano has been increasing and along with it the frequency occurrence of certain long-period (LP) signals. In this work, 6 families of LP signals were identified, with 83 total events. These events show energy concentrated mainly in the range of frequencies between 1 and 3 Hz, significant variations in amplitude, and some locations on the SW flank of the volcano at 1900 m.a.s.l. (corrected for site effects). The LP signals are interpreted as linked to the interaction between the fluids of the active hydrothermal system and a fault system (NE-SW direction) in the west slope of the Irazú volcano, but without being associated with magma ascent. This contribution provides useful information for the evaluation of the volcanic hazard at Irazú volcano, in terms of the analysis of possible precursors.