'qORDIC ASSOCIATION FOR APPLIED GEOPHYSICS 6 3

sented. They illustrate how depth information obtained from seismic reflection surveys can be laterally extrapolated by use of gravimetry.

This investigation also shows how modelling of gravity data is facilitated when combined with reflection seismics.

The MINILOC m e t h o d - a new approach to shallow seismic refraction

Johan Nissen ABEM, Box 20086, S-16102 Bromma, Stockholm, Sweden

The MINILOC concept of seismic refrac- tion consists of: - a new seismograph; - new field-procedures; - new build-in interpretation software.

The instrument is a three-channel seismo- graph with high resolution and large dynamic range. Due to the principle of reciprocity, the traditional multi-channel seismic registration is replaced by a three-channel registration and multiple (36 shots). This gives a more flexible methodology and a higher data quality (no correlated noises). Furthermore the instru- mentat ion becomes less involved and can be operated by one or two operators.

All functions in the seismograph are con- trolled via a menu-driven control program. Data processing and interpretation consist of: - first break picking; - ray-tracing optimization.

This interpretation technique combines the ray-tracing method with well-known methods for parameter fitting. As a result, a complete cross section with several layers and varying layer thickness can be generated automati- cally. The optimal model is the model giving min imum deviation between measured first- arrival times and calculated times.

Examples of MINILOC data and interpre- tation are presented and discussed.

Digital image processing of satellite images and aerial photos

J . F . Adamsen Operationsanalysekontoret, Jydsk Telefon A/S, Sletvej 30, 8310 Tranbjerg J, Denmark

A presentation of applicational uses of digi- tal satellite images or aerial photos as large scale/detailed mapping material. Resource mapping environmental surveying, technical

planning, registration, administration and other uses of maps may be input or output from a geographical information system (GIS) based on this mapping material.