Electrical Properties and Anisotropy of Schists and Fault Rocks from New Zealand’s Southern Alps under Confining Pressure

Magnetotelluric models spanning the Pacific–Australian Plate boundary in New Zealand’s South Island indicate a localized zone of low electrical resistivity that is spatially coincident with ductile mid-crustal part Alpine Fault Zone (AFZ). We explored source this anomaly by measuring properties samples collected from surface outcrops approaching AFZ have accommodated gradient systematic strain and deformation conditions. investigated effects tectonite fabric, fluid saturated pore/fracture networks conductivity on bulk response anisotropy measured under increasing confining pressures up to 200 MPa. find porosity increase while change pressure (? (??/??)/? (peff)) decreases AFZ, indicating controlled pore modified during progressive metamorphism. Conversely, mylonites exhibit relatively resistivities at porosities, lower ? (peff) than schists. These findings transition both distribution charge transport processes rocks experienced grain size reduction mixing phases development mylonitic fabrics due creep shear within AFZ.