Regional and residual gravity fields, central North Island, New Zealand

Regional components of the central North Island Bouguer and isostatic gravity anomaly fields are presented as third‐degree, two‐way polynomials. The Bouguer regional contours strike northeast, except in the Bay of Plenty region, where contours parallel the coast. The isostatic regional contours strike uniformly north‐east and go through a maximum which coincides with the axis of epicentres of intermediate depth earthquakes. The residual isostatic field shows four prominent negative anomalies in Central Volcanic Zone; three of these coincide with centres of rhyolitic volcanism.