The improved M02A version of the M0 (mechanical and optical)
 type of accelerograph, currently in use in the N.Z. strong-motion recorder network is described. The improvements relate mainly to
 the mechanical drive, including the film rewind, and to the
 electronics for the timing features. In particular the elapsed
 time from a previous visit to the instrument is obtained by interrogating a clock during the running of the film. Production 
of the M02 instrument has been suspended in favour of the M02A and all the instruments in the N.Z. network will be converted to M02As.