TY - RPRT TI - Holocene geomagnetic secular variation recorded by volcanic deposits at Mount St. Helens, Washington AU - J.T. Hagstrum AU - R. Hoblitt AU - C. A. Gardner AU - T.E. Gray PY - 2001 DO - 10.1007/s00445-001-0178-x UR - https://pubs.usgs.gov/publication/70024989 ID - 70024989 ER -