Technical Papers - Airborne Magnetics

iSPI^TM - the Improved Source Parameter Imaging Method

Richard Smith and Jeffrey B. Thurston, Fugro Airborne Surveys, 2060 Walkley Road, Ottawa, Ontario, Canada, K1G 3P5
Ting-Fan Dai and Ian N. MacLeod, Geosoft Inc., 8^th Floor, 85 Richmond St. West, Toronto, Ontario, Canada, M5H 2C9.

Abstract

Interpretation of an anomalous magnetic response involves determining the parameters that characterise the source of the anomaly. The depth to the top of the structure is a parameter that is commonly sought, and the Source Parameter Imaging^TM (SPI^TM) method is one way of determining this depth estimate. One advantage of the SPI method is that the depths can be displayed on an image. Typically there can be one image for an assumed contact (fault) model and another image for an assumed dipping thin sheet (dyke) model. The depth estimate obtained will depend on the model assumed.

An improvement to the source parameter imaging method extends the method to horizontal cylinders and at the same time allows the most appropriate model to be determined automatically. This model can be displayed on an image and the correct depth estimate for each anomaly can also be determined. The depth estimates can therefore be summarised onone map independent of an assumed model.

The images generated from synthetic and field data show that the improved SPI method makes the task of interpreting magnetic data significantly easier.

Published in Geophysical Prospecting, March, 1998, Volume 46, pages 141-151.

©1998, European Association of Geoscientists & Engineers. Single copies of the article may be printed for personal reference, but the article may not be reproduced in paper for bulk copies. Reprint copies must be purchased from the Blackwell Science. For more information on Geophysical Prospecting see the Blackwell Science website. 

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