The scaling relationship between self-potential and fluid flow on Masaya volcano, Nicaragua

摘要

The concurrent measurement of self-potential (SP) and soil CO_2 flux (F_s~(CO_2)) in volcanic systems may be an important tool to monitor intrusive activity and understand interaction between magmatic and groundwater systems. However, quantitative relationships between these parameters must be established to apply them toward understanding processes operating at depth. Power-law scaling exponents calculated for SP and F_s~(CO_2) measured along a fault on the flanks of Masaya volcano, Nicaragua indicate a nonlinear relationship between these parameters. Scaling exponents suggest that there is a diminishing increase in SP with a given increase in F_s~(CO_2), until a threshold (log F_s~(CO_2)≈2.5gm~(-2)d~(-1)) above which SP remains constant with increasing F_s~(CO_2). Implications for subsurface processes that may influence SP at Masaya are discussed.