Publication Date:
2021-06-15
Description:
Villarrica volcano (Chile) is one of the most active volcanoes in South America.
Its activity is currently characterized by continuous degassing from a summit lava
lake/vent punctuated by explosive events. During November 2004 a multidisciplinary
experiment was deployed for a 10-d period to define the style of emission and infer
shallow conduit dynamics at this basaltic center. This involved collection of
thermal, seismic and infrasonic data to describe the background activity confined inside
the crater, and use of samples to texturally and chemically characterize the ejecta from
more energetic explosions able to attain the crater rim. The background activity was
characterized by gas bursting with a frequency of 9 events per minute. This involved
emission of gas puffs fed by bubble bursting, with larger bursts emplacing sheets of
magma onto the lower crater walls. The ejecta population from the more energetic events
was characterized by the coexistence of both scoriae and golden pumice. These two
types of clasts have different textures but identical glass compositions, suggesting that
they underwent different conduit histories. The golden pumice is interpreted as the
expanding inner part of a short-lived jet fed by a rapidly ascending, magma batch. The
scoria forms the outer portion of the jet and comprises degassed material entrained during
passage of the fresh batch through material residing in the upper-most portion of the
conduit. We thus have a largely degassed upper column that feeds persistent
bubble bursting, through which fresh batches occasionally rise to feed events of relatively
higher energy.
Description:
Published
Description:
B08206
Description:
2.3. TTC - Laboratori di chimica e fisica delle rocce
Description:
JCR Journal
Description:
reserved
Keywords:
basaltic activity
;
remote sensing
;
05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
