JV3 Geophysical Imaging and Monitoring of Volcanoes (IAVCEI, IASPEI, IAGA)

Joint Inter-Association Symposium



28-Jun-2015, 16:30 - 18:00


 
Abstract content:

Shallow structure of Solfatara Volcano revealed by joining 2D seismic reflection and electric profiles with CO2 and soil temperature measurements

The MedSuV - RICEN project includes a series of geophysical and geochemical experiments carried out within Solfatara Volcano, with the aim of studying changes in the properties of the medium at small scales through repeated high-resolution multi-parameter observations over time. The investigated area, (Solfatara), is the most active volcano of Campi Flegrei Caldera, Italy, and it is presently characterized by an intense hydrothermal shallow activity, which results in fumarolic emission and a gas release of approximately 1,500 tons per day.

We present here the preliminary results from two very-high resolution seismic reflection and electric resistivity profiles that were acquired in the crater along coincident positions in May and November 2014, along with CO2 flux and surface temperature measurements. The reflection profiles provide the first high-resolution seismic images of Solfatara crater, depicting a slightly asymmetrical structure, whose bottom is found at about 400 ms TWT. Seismic data also show distinctive anomalous amplitudes in at least two narrow areas, which may be indicative of gas escaping along pre-exisiting sub-vertical fault and fractures. The assumed degassing pathways intersect a strong horizontal reflector at about 100 ms TWT and reach the surface of the crater. Moreover, both electric and seismic data suggest the presence of low- resistivity dome shaped structure, buried in the centre of the volcano at a minimum depth of 50 m and matching with a high C02 and high soil temperature at surface.

Our results will provide a solid framework to constrain the near-surface geological interpretation of such a complex area and to better understand and relate temporal changes of the other measured parameters to the shallow geological structure of the crater.

 
Author(s):
P.P. Bruno1, V. Di Fiore2, G. Festa3, M. Gresse4, S. Maraio5, I. Nazzaro6, J. Vandemeulebrouck4.
1The Petroleum Institute, Dept. of Petroleum Geosciences, Abu Dhabi, United Arab Emirates.
2CNR, Ist. Ambiente Marino e Costiero, Napoli, Italy.
3Università di Napopli "Federico II", Dip. di Fisica, Napoli, Italy.
4Université Savoie, Institut des Sciences de la Terre, Grenoble, France.
5Università Alma Mater Studiorum, Dip. Scienze Biologiche Geologiche e Ambientali, Bologna, Italy.
6INGV, Sede Irpinia, Grottaminarda AV, Italy.

 

Keywords:
seismic reflection     seismic imaging     high-resolution     Solfatara Volcano     Campi Flegrei