I JUNE 1961 



Vi-\ 





1500 



2000 2100 2200 



FIGURE 20 Nine-hour gravimeter recording beginning 1315 local time (2315Z) 1 June 1961 on ARLIS II 



2042 2041 2040 2039 2038 2037 2036 2035 2034 2033 20M 2031 



FIGURE 21 Expansion of high-amplitude, short-period event shown in figure 20 



3^ 



