Publication Date:
2017-04-04
Description:
Using constraints from literature data on the petrology and texture of erupted material from Stromboli and geochemical
measurements of gas emissions together with a model of gas solubility we construct a conceptual model of quiescent degassing for
this volcano. We find that within a pressure range between 100 MPa and 50 MPa (∼3.6 km and ∼1.8 km depth respectively)
vesiculating magma ascending within the conduit becomes permeable to gas flow and a transition from closed- to open-system
degassing takes place. Above the transition, gas, rich in the most insoluble gases, flows up through degassing magma, and thereby
becomes enriched in more soluble gases during ascent to the surface. The final gas emission is therefore a superposition of gases
released from magma above the percolation transition and gas that has evolved in closed-system below the transition.
Steady-state gas release from Stromboli can only be sustained via magma circulation, driven by the density variation between
ascending vesiculating magma and descending degassed magma. By balancing the buoyant force of ascending vesiculating magma
against the viscous resistance produced by travelling through descending, degassed magma in a simple flow model we determine
that a cylindrical conduit diameter of 2.5–2.9 m produces the magma mass flow rate of 575 kg s−1, required to account for the
observed quiescent SO2 gas flux on Stromboli of ∼2.3 kg s−1 (200 td−1).
Description:
Published
Description:
46–60
Description:
1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
Description:
JCR Journal
Description:
reserved
Keywords:
Stromboli
;
gas
;
04. Solid Earth::04.08. Volcanology::04.08.01. Gases
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink
