Séminaire de Vyacheslav M. Zobin

Mercredi 17 Mai à 14h dans la salle des séminaires (1.10) :

Vyacheslav M. Zobin,  Centro Universitario de Estudios Vulcanológicos, Universidad de Colima, Colima, México 

Title: Seismic signals of rockfalls as indicators of the origin of lava fragments emplaced during the 2010 endogenous and exogenous growth in the crater of Volcán de Colima, México 

Abstract 

The 2010-2011 exogenous emplacement of lava lobe during the 2007-2011 lava dome growth at andesitic Volcán de Colima, México interrupted the previous endogenous regime and allowed us to obtain the seismic signals associated with rockfalls triggered by both exogenous and endogenous growth. We analyzed a total of 410 seismic signals of rockfalls with durations from 50 to 150 s recorded during January-April 2010. Two characteristic populations of seismic signal peak frequencies were identified: a low frequency (LF) group (mean = 1.76±0.44 Hz) and a high frequency (HF) group (mean = 3.13±0.63 Hz), associated respectively with rockfalls caused by endogenous and exogenous growth in the crater. Application of the Kolmogorov-Smirnov test showed at 0.01 significance level that the databases of LF and HF seismic signals of rockfalls belong to different samples and may be considered as having the different origin. The results show that the spectral properties of the seismic signals produced by rockfalls may serve as indicators of the origin of falling lava fragments and thus can be used to monitor effusive volcanic activity.