[1] CARNEGIE INST WASHINGTON,DEPT TERRESTRIAL MAGNETISM,WASHINGTON,DC 20013
[2] BROWN UNIV,DEPT GEOL SCI,PROVIDENCE,RI 02912
[3] HASLER RES CTR,APPL RES LAB,GOLETA,CA 93017
[4] METHODS & APPL LAB,APPL RES LAB,SUNLAND,CA 91040
[5] BROWN UNIV,MAT RES LAB,PROVIDENCE,RI 02912