Dept. Earth & Environmental Science, N.M. Inst. of Mining & Technology, 801 Leroy Place, Socorro, NM 87801 ; Departamento de Geofisica. Escuela Politecnica Nacional, Ladron de Guevara s/n, Quito, 17-1-2759 Ecuador
Dept. Earth & Environmental Science, N.M. Inst. of Mining & Technology, 801 Leroy Place, Socorro, NM 87801
Dept. Earth & Environmental Science, N.M. Inst. of Mining & Technology, 801 Leroy Place, Socorro, NM 87801
Dept. Earth & Environmental Science, N.M. Inst. of Mining & Technology, 801 Leroy Place, Socorro, NM 87801