Zeta potential estimation of volcanic rocks on 11 island arc‐type volcanoes in Japan: Implication for the generation of local self‐potential anomalies

Abstract

[1] From streaming potential measurements, we deduced the zeta potential of 73 volcanic rock samples collected in 11 volcanoes where self-potential (SP) surveys had also been conducted. Experiments with crushed rock samples and 0.001 mol/L NaCl solution showed a large variation in streaming potential coefficient, which ranged from À2860 to 2280 mV/MPa (deduced zeta potential ranged from À45.1 to 37.2 mV). Among the 73 samples, 9 samples showed positive values, and 11 samples showed small absolute values less than 10 mV. Even in a volcano, the zeta potential values of rocks were sometimes highly variable. To investigate the reason for the variation in zeta potential, we performed X-ray fluorescence (XRF) measurements on the rock samples. However, no significant correlations between zeta potential (or isoelectric point) and weight percentage of major elements were found, implying that the zeta potential of the volcanic rocks is not controlled by chemical composition but by mineralogical composition or crystalline structure. In volcanic areas, rocks with positive or small absolute values of zeta potential, which are considered to be unusual, frequently exist in areas along with local positive SP anomalies. Although positive SP anomalies are usually interpreted as an indication of hydrothermal upflow, this correlation suggests that in addition to the groundwater flow pattern, the polarity of zeta potential should also be considered for interpretation of SP data. Therefore, in cases where detailed zeta potential measurements have not been conducted, local positive SP anomalies should be interpreted with caution.Citation: Aizawa, K., M. Uyeshima, and K. Nogami (2008), Zeta potential estimation of volcanic rocks on 11 island arc-type volcanoes in Japan: Implication for the generation of local self-potential anomalies,

Heat and Mass Transport in a Vapor‐Dominated Hydrothermal Area in Yellowstone National Park, USA: Inferences From Magnetic, Electrical, Electromagnetic, Subsurface Temperature, and Diffuse CO2 Flux Measurements

“…The strong correlation between the distributions of SP anomalies and magnetic susceptibility and the lack of spatial correlation with the distribution of CO 2 flux, heat flux, subsurface temperature, and shallow electrical conductivity (Figure S6) suggests that the distribution of the SP anomalies is decoupled from the thermal plume structure and more likely related to a process that also affects the magnetic susceptibility. Therefore, we propose that the negative SP anomalies result from the low pH near the ground surface around the mud pool, affecting the sign of the streaming coupling coefficient (e.g., Aizawa et al, ; Byrdina et al, ; Revil & Pezard, ; Text S5). The low pH is also consistent with the decrease in magnetic susceptibility due to dissolution of magnetic minerals in presence of acid‐sulfate waters.…”

Importance of structural history in the summit area of Stromboli during the 2002–2003 eruptive crisis inferred from temperature, soil CO2, self-potential, and electrical resistivity tomography

“…There is generally a positive excess of charge in the pore water to compensate the negative charge on the mineral surface (Revil and Leroy, 2001). However, recent laboratory experiments demonstrated that, in some cases, the charge of the pore water can be negative to compensate a positive charge on the mineral surface (Hase et al, 2003;Guichet et al, 2006;Aizawa et al, 2008). This is however not the case at Stromboli (Revil et al, 2004).…”

A geochemical and geophysical investigation of the hydrothermal complex of Masaya volcano, Nicaragua

“…In this study, however, and based on previous work, the main resistivity contrasts are considered to be associated with the pathway of the main ground water flow (MacNeil et al, 2007;Mauri et al, 2010). A more detailed description of selfpotential electrical generation can be found in the literature (Ewing, 1939;Poldini, 1939;Corwin and Hoover, 1979;Avena and DePauli, 1996;Johnston et al, 2001;Guichet and Zuddas, 2003;Hase et al, 2003;Zlotnicki and Nishida, 2003;Lénat, 2007;Aizawa et al, 2008;Finizola et al, 2009;Jouniaux et al, 2009). …”

“…EK is affected by several key parameters including the chemical composition of the water and the zeta potential, which is the electrical expression of the interaction between ions along the Helmholtz double layer (Hase et al, 2003;Aizawa et al, 2008). With an increase in flow pressure, the quantity of ions removed from the surface of minerals constituting the rock will increase.…”

“…The electrokinetic process (EK) is a complex phenomenon, which occurs when water flows through a porous medium (e.g., Corwin and Hoover, 1979;Jouniaux and Pozzy, 1995;Hase et al, 2003;Aizawa et al, 2008;Jouniaux et al, 2009). EK is affected by several key parameters including the chemical composition of the water and the zeta potential, which is the electrical expression of the interaction between ions along the Helmholtz double layer (Hase et al, 2003;Aizawa et al, 2008).…”