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The emission of occluded gas from rocks as a function of stress: Its possible use as a tool for predicting earthquakes
Author(s) -
Giardini A. A.,
Subbarayudu Gogineni V.,
Melton Charles E.
Publication year - 1976
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/gl003i006p00355
Subject(s) - igneous rock , gneiss , metamorphic rock , geology , stress (linguistics) , crust , volume (thermodynamics) , sedimentary rock , mineralogy , petrology , geochemistry , thermodynamics , linguistics , philosophy , physics
Occluded gases were studied from fifteen types of rock, including igneous, metamorphic and sedimentary. The specimens were stressed to a crushing failure at room temperature under a vacuum of about 10 −9 torr. The more abundant gases were H 2 , CH 4 , H 2 O, N 2 CO, O 2 and CO 2 . However, each rock released gas with a characteristic composition. The volume of gas released was a variable function of stress above a threshold value. The greatest rate of emission occurred over the latter 20% of the rock's ability to withstand stress. Analyses of stress‐released occluded gases (excluding water), released as a function of stress, are given for a granodiorite and a gneiss. Volumes (STP)of most gases observed prior to and upon failure of the rocks are equivalent to several hundred liters each per ton of rock. Stress‐induced emission of a widely distributed, highly mobile gas such as H 2 could serve as an useful indicator of a critical stress build‐up in the earth's crust.