Time marks (x) ore given every 48 hours 
133 
energy density f(cm/s)*'2 / cphj 
K1 
record no: o91023, sampling interval = 10-0 minutes 
□ -component (zone!) ^component (meridional) 
0.01 0,10 1.00 
frequency [eph] 
“20 0 20 40 
19. 3.1991 14:10 - 13, 4.1991 10:20 (UTC)