ULF/ELF polarimetry: observations of anomalous ULF signals preceding the Northridge earthquake of January 17, 1994

Jack Y. Dea; Peder M. Hansen; Wolfgang-Martin Boerner

doi:10.1117/12.300623

23 December 1997 ULF/ELF polarimetry: observations of anomalous ULF signals preceding the Northridge earthquake of January 17, 1994

Jack Y. Dea, Peder M. Hansen, Wolfgang-Martin Boerner

Author Affiliations +

Proceedings Volume 3120, Wideband Interferometric Sensing and Imaging Polarimetry; (1997) https://doi.org/10.1117/12.300623
Event: Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United States

Abstract

Continuous ULF background data are recorded at the Low Frequency Observatory in San Diego since 1990. Some 18 days preceding the large Northridge earthquake of January 17, 1994. Anomalous signals of approximately twice the background level were recorded. The timing of the anomalous signals, the return to normal levels after the quake and a delay in the onset of higher frequency anomalous signals all suggest a strong correlation of the anomalous signals with the events at Northridge. A simple model of migrating micro- fractures is used to explain the temporal characteristics of the signals.

Citation Download Citation

Jack Y. Dea, Peder M. Hansen, and Wolfgang-Martin Boerner "ULF/ELF polarimetry: observations of anomalous ULF signals preceding the Northridge earthquake of January 17, 1994", Proc. SPIE 3120, Wideband Interferometric Sensing and Imaging Polarimetry, (23 December 1997); https://doi.org/10.1117/12.300623

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