Active earth deformation

Abstract

The introduction (part I) notes the N.Z. Geological Survey's policy and practice on active earth deformation with its emphasis on standardisation and uniformity in the treatment of data and presentation of interpretations.

Part II defines the terminology relating to earth deformation, it classifies active faults and folds by strictly adhering to the available evidence of their past geological history of activity. Where evidence of past activity is missing, but the structure can be geologically identified and the absence of evidence can be shown to have been destroyed or obscured, criteria for classification as "Potentially Active" are presented.

The periodicity of movement and the risk of future movement are briefly discussed.

The need to separate data from interpretation is clearly indicated by the separate treatment in part III - presentation of data in geological maps and reports – and part IV Town Planning and Engineering Implications. The latter part requires the separate presentation of a Data Map and a Interpretative Map, and concise criteria are listed to achieve standardisation of interpretation.

The report ends with a brief and general discussion on the engineering implications of active earth deformation.