Pressure Controlled Permeability in a Conduit Filled with Fractured Hydrothermal Breccia Reconstructed from Ballistics from Whakaari (White Island), New Zealand
Breccia-filled eruption conduits are dynamic systems where pressures frequently exceed critical thresholds, generating earthquakes and transmitting fluids. To assess the dynamics of breccia-filled conduits, we examine lava, ash tuff, and hydrothermal breccia ballistics with varying alteration, veini...
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ftmdpi:oai:mdpi.com:/2076-3263/10/4/138/ 2023-08-20T04:10:19+02:00 Pressure Controlled Permeability in a Conduit Filled with Fractured Hydrothermal Breccia Reconstructed from Ballistics from Whakaari (White Island), New Zealand Ben M. Kennedy Aaron Farquhar Robin Hilderman Marlène C. Villeneuve Michael J. Heap Stan Mordensky Geoffrey Kilgour Art. Jolly Bruce Christenson Thierry Reuschlé agris 2020-04-11 application/pdf https://doi.org/10.3390/geosciences10040138 EN eng Multidisciplinary Digital Publishing Institute Natural Hazards https://dx.doi.org/10.3390/geosciences10040138 https://creativecommons.org/licenses/by/4.0/ Geosciences; Volume 10; Issue 4; Pages: 138 alteration porosity eruption fracture permeability Text 2020 ftmdpi https://doi.org/10.3390/geosciences10040138 2023-07-31T23:21:36Z Breccia-filled eruption conduits are dynamic systems where pressures frequently exceed critical thresholds, generating earthquakes and transmitting fluids. To assess the dynamics of breccia-filled conduits, we examine lava, ash tuff, and hydrothermal breccia ballistics with varying alteration, veining, fractures, and brecciation ejected during the 27 April 2016 phreatic eruption of Whakaari/White Island. We measure connected porosity, strength, and permeability with and without tensile fractures at a range of confining pressures. Many samples are progressively altered with anhydrite, alunite, and silica polymorphs. The measurements show a large range of connected porosity, permeability, and strength. In contrast, the cracked samples show a consistently high permeability. The cracked altered samples have a permeability more sensitive to confining pressure than the unaltered samples. The permeability of our altered ballistics is lower than surface rocks of equivalent porosity, illustrating that mineral precipitation locally blocked pores and cracks. We surmise that alteration within the conduit breccia allows cracks to form, open and close, in response to pore pressure and confining pressure, providing a mechanism for frequent and variable fluid advection pulses to the surface. This produces temporally and spatially variable geophysical and geochemical observations and has implications for volcano monitoring for any volcano system with significant hydrothermal activity. Text White Island MDPI Open Access Publishing New Zealand White Island ENVELOPE(48.583,48.583,-66.733,-66.733) Geosciences 10 4 138 |
institution |
Open Polar |
collection |
MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
alteration porosity eruption fracture permeability |
spellingShingle |
alteration porosity eruption fracture permeability Ben M. Kennedy Aaron Farquhar Robin Hilderman Marlène C. Villeneuve Michael J. Heap Stan Mordensky Geoffrey Kilgour Art. Jolly Bruce Christenson Thierry Reuschlé Pressure Controlled Permeability in a Conduit Filled with Fractured Hydrothermal Breccia Reconstructed from Ballistics from Whakaari (White Island), New Zealand |
topic_facet |
alteration porosity eruption fracture permeability |
description |
Breccia-filled eruption conduits are dynamic systems where pressures frequently exceed critical thresholds, generating earthquakes and transmitting fluids. To assess the dynamics of breccia-filled conduits, we examine lava, ash tuff, and hydrothermal breccia ballistics with varying alteration, veining, fractures, and brecciation ejected during the 27 April 2016 phreatic eruption of Whakaari/White Island. We measure connected porosity, strength, and permeability with and without tensile fractures at a range of confining pressures. Many samples are progressively altered with anhydrite, alunite, and silica polymorphs. The measurements show a large range of connected porosity, permeability, and strength. In contrast, the cracked samples show a consistently high permeability. The cracked altered samples have a permeability more sensitive to confining pressure than the unaltered samples. The permeability of our altered ballistics is lower than surface rocks of equivalent porosity, illustrating that mineral precipitation locally blocked pores and cracks. We surmise that alteration within the conduit breccia allows cracks to form, open and close, in response to pore pressure and confining pressure, providing a mechanism for frequent and variable fluid advection pulses to the surface. This produces temporally and spatially variable geophysical and geochemical observations and has implications for volcano monitoring for any volcano system with significant hydrothermal activity. |
format |
Text |
author |
Ben M. Kennedy Aaron Farquhar Robin Hilderman Marlène C. Villeneuve Michael J. Heap Stan Mordensky Geoffrey Kilgour Art. Jolly Bruce Christenson Thierry Reuschlé |
author_facet |
Ben M. Kennedy Aaron Farquhar Robin Hilderman Marlène C. Villeneuve Michael J. Heap Stan Mordensky Geoffrey Kilgour Art. Jolly Bruce Christenson Thierry Reuschlé |
author_sort |
Ben M. Kennedy |
title |
Pressure Controlled Permeability in a Conduit Filled with Fractured Hydrothermal Breccia Reconstructed from Ballistics from Whakaari (White Island), New Zealand |
title_short |
Pressure Controlled Permeability in a Conduit Filled with Fractured Hydrothermal Breccia Reconstructed from Ballistics from Whakaari (White Island), New Zealand |
title_full |
Pressure Controlled Permeability in a Conduit Filled with Fractured Hydrothermal Breccia Reconstructed from Ballistics from Whakaari (White Island), New Zealand |
title_fullStr |
Pressure Controlled Permeability in a Conduit Filled with Fractured Hydrothermal Breccia Reconstructed from Ballistics from Whakaari (White Island), New Zealand |
title_full_unstemmed |
Pressure Controlled Permeability in a Conduit Filled with Fractured Hydrothermal Breccia Reconstructed from Ballistics from Whakaari (White Island), New Zealand |
title_sort |
pressure controlled permeability in a conduit filled with fractured hydrothermal breccia reconstructed from ballistics from whakaari (white island), new zealand |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2020 |
url |
https://doi.org/10.3390/geosciences10040138 |
op_coverage |
agris |
long_lat |
ENVELOPE(48.583,48.583,-66.733,-66.733) |
geographic |
New Zealand White Island |
geographic_facet |
New Zealand White Island |
genre |
White Island |
genre_facet |
White Island |
op_source |
Geosciences; Volume 10; Issue 4; Pages: 138 |
op_relation |
Natural Hazards https://dx.doi.org/10.3390/geosciences10040138 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/geosciences10040138 |
container_title |
Geosciences |
container_volume |
10 |
container_issue |
4 |
container_start_page |
138 |
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1774724406802644992 |