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| Titel |
Hydrogeochemical precursors of strong earthquakes in Kamchatka: further analysis |
| VerfasserIn |
P. F. Biagi, R. Piccolo, A. Ermini, Y. Fujinawa, S. P. Kingsley, Y. M. Khatkevich, E. I. Gordeev |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 1, no. 1/2 ; Nr. 1, no. 1/2, S.9-14 |
| Datensatznummer |
250000015
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| Publikation (Nr.) |
 copernicus.org/nhess-1-9-2001.pdf |
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| Zusammenfassung |
| For many years, ion
and gas content data have been collected from the groundwater of three
deep wells in the southern area of the Kamchatka peninsula, Russia. In the
last ten years, five earthquakes with M > 6.5 have occurred within 250
km of the wells. In a previous study, we investigated the possibility that
the hydrogeochemical time series contained precursors. The technique used
was to assume that each signal with an amplitude of three times the
standard deviation is an irregularity and we then defined anomalies as
irregularities occurring simultaneously in the data for more than one
parameter at each well. Using this method, we identified 11 anomalies with
8 of them being possible successes and 3 being failures as earthquake
precursors. Precursors were obtained for all five earthquakes that we
considered. In this paper, we allow for the cross-correlation found
between the gas data sets and in some cases, between the ion data sets. No
cross-correlation has been found between gas and ion content data. Any
correlation undermines the idea that an anomaly might be identified from
irregularities appearing simultaneously on different parameters at each
site. To refine the technique, we re-examine the hydrogeochemical data and
define as anomalies those irregularities occurring simultaneously only in
the data of two or more uncorrelated parameters. We then restricted the
analysis to the cases of just the gas content data and the ion content
data. In the first case, we found 6 successes and 2 failures, and in the
second case, we found only 3 successes. In the first case, the precursors
appear only for three of the five earthquakes we considered, and in the
second case, only for two, but these are the earthquakes nearest to the
wells. Interestingly, it shows that when a strict set of rules for
defining an anomaly is used, the method produces only successes and when
less restrictive rules are used, earthquakes further from the well are
implicated, but at the cost of false alarms being introduced. |
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