Assessment of Topographic Lineaments Across Rotorua Geothermal Field, New Zealand

Abstract

Topographic lineaments were identified and traced from digital topographic data (25m grid) over the Rotorua area in the Taupo Volcanic Zone (TVZ), central North Island of New Zealand. Assuming that the lineaments represent faults and fractures, the result is presented as the variation of 'fault and fracture density' (FFD) defined as total length of lineaments per unit area oan/km2). The study did not reveal any coherent high FFD zone associated with the Rotorua geothermal field. A topographic correction was attempted by fitting a logarithmic function to the plot of average topographic gradient against FFD values, but this failed to enhance the FFD over the field where the terrain is almost flat. There are strong rdationships between high FFD zones and some major faults mapped in the Rotorua area.