ISSN:
1420-9136
Keywords:
Hydrogen
;
Soil gas
;
Fault
;
Earthquake
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract The concentration of H2 in soil gases has been measured weekly at five stations on the Atotsugawa and Ushikubi faults in northern central Main Island, Japan, since 1981 in search of possible relationship with earthquakes. The observed H2 concentration varies from lower than 1 ppm to 7.8% in time and place. When a large earthquake (M: 7.7, epicenter distance: 486 km) occurred on 26 May 1983, an outstanding discharge of H2 was observed at all five stations, preseismically at three of them, and coseismically at the other two. Simultaneous H2 emission was also observed at some stations in seven other occasions. These periods of unusual H2 discharge nearly coincided with occurrences of major earthquakes in Japan, but not of local minor earthquakes along the Atotsugawa fault. This fault, being a deep fracture zone, may be sensitive to large-scale crustal stress changes which incidentally cause the major earthquakes. Increased H2 may be produced by rock fracture caused by the increased stresses on the fault and by the earthquakes themselves. Local minor earthquakes along Atotsugawa fault with magnitude lower than 3 may be unable to cause sufficient rock fracture to produce significant H2.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00874592
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