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IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS009 Poster presentation 2049
Groundwater geochemical disturbances related to seismicity revealed in
Kamchatka (Russia) during the last 30 years: further results
Prof. Pier Francesco Biagi
Department of Physics University of Bari IASPEI
Maggipinto Giuseppe, Maggipinto Tommaso, Piccolo Roberto, Minafra Antonio,
Ermini Anita, Capozzi Vito, Khatkevich Yuri, Gordeev Evgeni
For many years, ion and gas content data have been collected from the groundwater of six deep wells
and two natural springs in the southern area of the Kamchatka peninsula, Russia. In previous studies
developed in 1998-2000, the possibility that the hydrogeochemical time series contained precursors was
investigated. The technique used was to filter the raw data from short and long variations, to assume
that each signal with an amplitude larger than three times the standard deviation is an irregularity and
then to define anomalies as irregularities occurring simultaneously in the data for more than one not
correlated parameter at each measurement site. Using this method, as main result, preseismic
anomalies with a duration of some month were revealed on the occasion of the March 2, 1992 (M =
7.0) and January 1, 1996 (M = 6.9) earthquakes, i.e. the largest events occurred quite near to the
hydro-geochemical network in last thirty years. Another result was a preseismic anomaly with a duration
of some days pointed out on the occasion of the July 21, 1996 earthquake (M = 7.1), that was a very
shallow event. The previous anomalies appeared only in some measurement site of the network. Now
the more extended (up to December 2005) data sets were investigated using directly the raw data,
without any filtering technique. The present analysis has confirmed the previous results adding some
information as the appearance of possible preseismic anomalies in other measurement sites of the
network and the existence of long term (some year) precursors and of post seismic effects.
Keywords: precursors, geochemistry, kamchatka