Geomagnetic micropulsations

Abstract

A field station for the recording of the horizontal magnetic field and magnetotelluric study was set up in the Wairarapa. The horizontal magnetic field had the following properties: (a) a diurnal variation in period with the minimum period around mid-day, (b) the day-time activity was predominately linear or anticlockwise in the sense of rotation while the night-time pt activity was clockwise, (c) the direction of the vector was mainly north-south geographically but in the morning the direction rotated 180° and in the late afternoon it rotated 30 °. Various partially successful models were used to explain these properties. From the magnetotelluric study, the resistivity as a function of depth was calculated. A surface layer was found of about 10 Km and with resistivity of the order of 10 ohm.metre. Beneath this layer the resistivity increased to several hundred ohm.metre.