Frequency analyses of magnetograms from Port Moresby Observatory have disclosed an apparently new feature of the geomagnetic field. After the great 1960 Chilean earthquake the local field contained low‐energy harmonics with periods 43.1, 29.0, 22.4 min approximately, near those of the three gravest torsional oscillations of the earth, 0T2, 0T3, 0T4. These harmonics were absent just before the earthquake. The methods of analysis, characteristics of the magnetograms, and possible mechanisms of generation are discussed briefly.

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