Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 11, 1839-1844, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
05 Jul 2011
Standardised Radon Index (SRI): a normalisation of radon data-sets in terms of standard normal variables
R. G. M. Crockett and C. P. Holt Data Analysis Group, School of Science and Technology, University of Northampton, Northampton, UK
Abstract. During the second half of 2002, from late June to mid December, the University of Northampton Radon Research Group operated two continuous hourly-sampling radon detectors 2.25 km apart in the English East Midlands. This period included the Dudley earthquake (ML = 5, 22 September 2002) and also a smaller earthquake in the English Channel (ML = 3, 26 August 2002). Rolling/sliding windowed cross-correlation of the paired radon time-series revealed periods of simultaneous similar radon anomalies which occurred at the time of these earthquakes but at no other times during the overall radon monitoring period. Standardising the radon data in terms of probability of magnitude, analogous to the Standardised Precipitation Indices (SPIs) used in drought modelling, which effectively equalises different non-linear responses, reveals that the dissimilar relative magnitudes of the anomalies are in fact closely equiprobabilistic. Such methods could help in identifying anomalous signals in radon – and other – time-series and in evaluating their statistical significance in terms of earthquake precursory behaviour.

Citation: Crockett, R. G. M. and Holt, C. P.: Standardised Radon Index (SRI): a normalisation of radon data-sets in terms of standard normal variables, Nat. Hazards Earth Syst. Sci., 11, 1839-1844,, 2011.
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