Anomalies in the chemical composition of underground water due to the 2d March 1992 earthquake (Mw=6.9), Kamchatka

Category: 13-1
G.N. Kopylova, S.V. Boldina

 

UDC 556.314:550.344.37:550.34.013.4 

 

 

G.N. Kopylova, S.V. Boldina

 

Kamchatka Branch, Geophysical Survey, Russian Academy of Sciences,

Petropavlovsk-Kamchatsky, Russia

 

Abstract

The anomalies in groundwater chemistry due to the 2d March 1992 Kamcatkan earthquake (Mw=6.9) are analyzed taking into account the physical mixing of two chemically contrast fluids in waterbearing stratum connected with the flowing wells Moroznay-1 and Pinachevo-GK-1, Kamchatka. Precursory and postseismic changes were marked out in time series of groundwater chemistry. The transient times of water pressure relaxation and mixed water flow in waterbearing stratum are estimated for the preparation stage of the earthquake. The chemical composition of two mixing waters is estimated for the well Moroznay-1 using the double porosity model for waterbearing stratum. An increase of water inflow with heightened sulphate-ion, calcium and sodium concentrations from low permeability medium into fractures had taking place on the preparation stage of the earthquake.

Keywords: flowing well, chemical composition, chemical analysis, earthquake, hydrochemical precursor, modeling, waterbearing stratum.

 

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