The principal aim of the present network of strong motion accelerographs is to record the response of structures to earthquakes, and instruments are concentrated in the larger cities where modern, tall buildings are found. However, the behaviour of structures during earthquakes is now comparatively well understood. At the present time, estimating design ground motions is the weakest part in the process of designing structures to resist earthquakes. There is a strong need for more recordings of ground shaking, particularly
sets of several accelerograms from single earthquakes. It is not certain that the present accelerograph network would capture any significant record of strong motion during a major earthquake in New Zealand; and the chance of a set of three or more strong accelerograms being recorded is quite small. It is recommended that 25 additional instruments be installed promptly, to fill the main gaps in the present network, and to extend the capacity of the existing local network in the Wellington area.