 |
| Titel |
Quantification of magma ascent rate through rockfall monitoring at the growing/collapsing lava dome of Volcán de Colima, Mexico |
| VerfasserIn |
S. B. Mueller, N. R. Varley, U. Kueppers, P. Lesage, G. Á. Reyes Davila, D. B. Dingwell |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1869-9510
|
| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 4, no. 2 ; Nr. 4, no. 2 (2013-07-11), S.201-213 |
| Datensatznummer |
250017783
|
| Publikation (Nr.) |
 copernicus.org/se-4-201-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| The most recent eruptive phase of Volcán de Colima, Mexico, started in
1998 and was characterized by dome growth with a variable effusion rate,
interrupted intermittently by explosive eruptions. Between November 2009 and
June 2011, activity at the dome was mostly limited to a lobe on the western
side where it had previously started overflowing the crater rim, leading to
the generation of rockfall events. As a consequence of this, no significant
increase in dome volume was perceivable and the rate of magma ascent, a
crucial parameter for volcano monitoring and hazard assessment could no
longer be quantified via measurements of the dome's dimensions. Here, we
present alternative approaches to quantify the magma ascent rate. We
estimate the volume of individual rockfalls through the detailed analysis of
sets of photographs (before and after individual rockfall events). The
relationship between volume and infrared images of the freshly exposed dome
surface and the seismic signals related to the rockfall events were then
investigated. Larger rockfall events exhibited a correlation between its
previously estimated volume and the surface temperature of the freshly
exposed dome surface, as well as the mean temperature of rockfall mass
distributed over the slope. We showed that for larger events, the volume of
the rockfall correlates with the maximum temperature of the newly exposed
lava dome as well as a proxy for seismic energy. It was therefore possible
to calibrate the seismic signals using the volumes estimated from
photographs and the count of rockfalls over a certain period was used to
estimate the magma extrusion flux for the period investigated. Over the
course of the measurement period, significant changes were observed in
number of rockfalls, rockfall volume and hence averaged extrusion rate. The
extrusion rate was not constant: it increased from 0.008 ± 0.003 to 0.02 ± 0.007 m3 s−1 during 2010
and dropped down to 0.008 ± 0.003 m3 s−1 again in March
2011. In June 2011, magma extrusion had come to a halt. The methodology
presented represents a reliable tool to constrain the growth rate of domes
that are repeatedly affected by partial collapses. There is a good
correlation between thermal and seismic energies and rockfall volume. Thus
it is possible to calibrate the seismic records associated with the
rockfalls (a continuous monitoring tool) to improve volcano monitoring at
volcanoes with active dome growth. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|