Earthquakes have recently occurred under the North Island of New Zealand, near 39° S, 175° E, at various depths down to 600 km. First-motion patterns of apparently opposite sense have been found for two groups of earthquakes with virtually the same epicentre but depths of about 230 and 600 km respectively. First motions are referred to the focal sphere; the commonly used “extended distance” method of displaying the results has the disadvantage of giving undue prominence to readings from distant phases. Comparisons of these New Zealand earthquakes among themselves and with the deep Spanish earthquake of 1954 suggest that the mechanism of earthquakes is not so closely related to surface geological features as has been supposed.