A geophysical index to map alteration, permeability, and mechanical properties within volcanoes. Application to the soft volcanic rocks from Whakaari/White Island (New Zealand)
International audience The alteration of soft volcanic rocks (i.e., characterized by a low uniaxial compressive strength b35 MPa) can change their permeability and mechanical strength. We built an alteration indicator based on porosity and cation exchange capacity (CEC) to connect the degree of alte...
Published in: | Journal of Volcanology and Geothermal Research |
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Main Authors: | , , , |
Other Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2020
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Subjects: | |
Online Access: | https://hal.archives-ouvertes.fr/hal-03005820 https://hal.archives-ouvertes.fr/hal-03005820/document https://hal.archives-ouvertes.fr/hal-03005820/file/2020-JVGR-alteration%20index%20volcan.pdf https://doi.org/10.1016/j.jvolgeores.2020.106945 |
Summary: | International audience The alteration of soft volcanic rocks (i.e., characterized by a low uniaxial compressive strength b35 MPa) can change their permeability and mechanical strength. We built an alteration indicator based on porosity and cation exchange capacity (CEC) to connect the degree of alteration of soft volcanic rocks to their permeability and uni-axial compressive strength. The proposed empirical petrophysical relationships are validated using a dataset of 62 samples from Whakaari/White Island (New Zealand). Since porosity and CEC can be imaged with induced polarization , this geophysical method can be used to map permeability and mechanical properties for near-surface formations at active volcanoes worldwide. |
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