Vinciguerra, S;
Trovato, C;
Meredith, PG;
Benson, PM;
(2005)
Relating seismic velocities, thermal cracking and permeability in Mt. Etna and Iceland basalts.
International Journal of Rock Mechanics and Mining Sciences
, 42
(7-8)
pp. 900-910.
10.1016/j.ijrmms.2005.05.022.
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Abstract
We report simultaneous laboratory measurements of seismic velocities and fluid permeability on lava flow basalt from Etna (Italy) and columnar basalt from Seljadur (Iceland). Measurements were made in a servo-controlled steady-state-flow permeameter at effective pressures from 5–80 MPa, during both increasing and decreasing pressure cycles. Selected samples were thermally stressed at temperatures up to 900 °C to induce thermal crack damage. Acoustic emission output was recorded throughout each thermal stressing experiment. At low pressure (0–10 MPa), the P-wave velocity of the columnar Seljadur basalt was 5.4 km/s, while for the Etnean lava flow basalt it was only 3.0–3.5 km/s. On increasing the pressure to 80 MPa, the velocity of Etnean basalt increased by 45%–60%, whereas that of Seljadur basalt increased by less than 2%. Furthermore, the velocity of Seljadur basalt thermally stressed to 900 °C fell by about 2.0 km/s, whereas the decrease for Etnean basalt was negligible. A similar pattern was observed in the permeability data. Permeability of Etnean basalt fell from about 7.5×10−16 m2 to about 1.5×10−16 m2 over the pressure range 5–80 MPa, while that for Seljadur basalt varied little from its initial low value of 9×10−21 m2. Again, thermal stressing significantly increased the permeability of Seljadur basalt, whilst having a negligible effect on the Etnean basalt. These results clearly indicate that the Etnean basalt contains a much higher level of crack damage than the Seljadur basalt, and hence can explain the low velocities (3–4 km/s) generally inferred from seismic tomography for the Mt. Etna volcanic edifice.
| Type: | Article |
|---|---|
| Title: | Relating seismic velocities, thermal cracking and permeability in Mt. Etna and Iceland basalts |
| Location: | Bad Honnef, GERMANY |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.ijrmms.2005.05.022 |
| Publisher version: | https://doi.org/10.1016/j.ijrmms.2005.05.022 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Science & Technology, Technology, Physical Sciences, Engineering, Geological, Mining & Mineral Processing, Engineering, physical properties, lava flows, columnar basalts, thermal cracking, LOWER CRUST, VOLCANO, ERUPTION, FAILURE, ROCKS |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10117183 |
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