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Experimental studies of the mechanisms of seismo‐geochemical precursors
Author(s) -
Fongliang Jiang,
Guiru Li
Publication year - 1981
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl008i005p00473
Subject(s) - geology , aquifer , groundwater , crust , seismology , deformation (meteorology) , shear (geology) , stress (linguistics) , stress field , epicenter , geophysics , petrology , geotechnical engineering , linguistics , oceanography , philosophy , physics , finite element method , thermodynamics
The following aspects of modeling experiments on seismo‐geochemical precursors are described: (1) gas emission during laboratory stress loading and rupture of rocks, (2) field measurements with explosion sources, (3) aquifer mixing tests in the field, (4) experimental studies of physico‐chemical processes caused by stress events. From these studies, three conclusions have been drawn: (1) Long‐term seismo‐geochemical anomalies appear to be related to the stage of elastic deformation of rocks under stress loading prior to a seismic event. Short‐term anomalies appear to be related to the plastic deformation of rock, and spike‐like anomalies appear to be related to shear displacement before an earthquake. (2) Anomalous changes in chemical composition of groundwater and the escape of gases from the ground appear to result from rock fracturing which opens up pathways for the upward migration of water from deep, confined aquifers, and for the upward migration of gases from the deeper crust. (3) Chemical reactions induced by increasing stress in the epicentral region may result in the anomalous changes in chemical composition of groundwater observed before some large earthquakes.