Conduit resonance models for long-period seismicity at Galeras volcano (Colombia), during 2004–2010

Abstract

This study analyzes the long-period (LP) seismicity of Galeras volcano from the period 2004–2010, based on resonance models of a magma column. In this model an initial disturbance is propagated through the magma column's walls in the form of waves until it reaches a receiver located on the surface. The input parameters for the crust and magma were obtained from previous studies, and the solution of the systems of equations was found using a finite element method. Models for two groups of LP events were found: group G1 associated with the emplacement of the lava domes in 2006 and 2008, and group G2 related to the seismicity preceding the emplacement of these domes. Group G1 is modeled by the resonance of a magma column about 2800 m long with its top near the surface and group G2 is related to a column close to 2000 m in length. The main frequency of initial perturbation differs between the groups. Additionally, the results of this study cast doubt on the effectiveness of location methods of fluid-related seismicity based on amplitude attenuation.