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The Sacks-Evertson borehole volumetric strainmeter has proven to have resolution of better than 10-11 at various locations on land , including San Andreas , California , Iceland , and Japan ( Sacks et al ., 1978 ; Linde et al ., 1988 , 1993 , 1996 ) . There 's one by Benhamou , et al ., 1988 , which was adjusted for smoking and showed relative risk of 2.14 .