Revision History for U.S. Geological Survey Open-File Report 2009-1226 Proceedings of the XIIIth IAGA Workshop on Geomagnetic Observatory Instruments, Data Acquisition, and Processing Edited by Jeffrey J. Love --------------------------- Revised May 13, 2010 --------------------------- Entire article replaced: Minamoto, Yasuhiro, Ongoing Geomagnetic Field 1-Second Value Measurement by JMA, p. 190.