Monitoring radon content



The report in the November issue of EOS describing Chinese research on earthquake prediction states that ‘a systematic field program of monitoring the radon content of water has yet to be established in the United States.’ This is incorrect: at least one such program has been in operation for 16 months. Since August 1974, my laboratory has been monitoring radon, helium, and He3/He4 ratios in thermal springs and wells along the major faults in southern California. A network of sampling sites has been set up on the Elsinore, San Jacinto, Mission Creek, Banning, and San Andreas faults, covering the area between San Bernardino and the Mexican border. The network includes 18 primary sampling points, which are sampled monthly, and 12 secondary locations, which are sampled less frequently.