Exploring uncertainty in the Earth Sciences - the potential field perspective
Abstract
Interpretation of gravity and magnetic anomalies is mathematically non-unique because multiple theoretical solutions are possible. The mathematical label of 'non-uniqueness' can lead to the erroneous impression that no single interpretation is better in a geologic sense than any other. The purpose of this talk is to present a practical perspective on the theoretical non-uniqueness of potential field interpretation in geology. There are multiple ways to approach and constrain potential field studies to produce significant, robust, and definitive results. For example, a smooth, bell-shaped gravity profile, in theory, could be caused by an infinite set of physical density bodies, ranging from a deep, compact, circular source to a shallow, smoothly varying, inverted bell-shaped source. In practice, however, we can use independent geologic or geophysical information to limit the range of possible source densities and rule out many of the theoretical solutions. We can further reduce the theoretical uncertainty by careful attention to subtle anomaly details. For example, short-wavelength anomalies are a well-known and theoretically established characteristic of shallow geologic sources. The 'non-uniqueness' of potential field studies is closely related to the more general topic of scientific uncertainty in the Earth sciences and beyond. Nearly all results in the Earth sciences are subject to significant uncertainty because problems are generally addressed with incomplete and imprecise data. The increasing need to combine results from multiple disciplines into integrated solutions in order to address complex global issues requires special attention to the appreciation and communication of uncertainty in geologic interpretation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMPA21B1874S
- Keywords:
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- 6309 POLICY SCIENCES Decision making under uncertainty;
- 1517 GEOMAGNETISM AND PALEOMAGNETISM Magnetic anomalies: modeling and interpretation;
- 1219 GEODESY AND GRAVITY Gravity anomalies and Earth structure;
- 0920 EXPLORATION GEOPHYSICS Gravity methods