In answer to my own question, they were a little under 4 months apart. The last big Antarctic quake was 03/25/98 and the PNG tsunami producer was 07/17/1998. There were a few other large ones between them. I was trying to see if there was a connection between the two, but apparently not.

PDE 1998 03 25 031225.07 -62.88 149.53 10 8.80 MEGS ..FG .......
PDE 1998 03 29 194816.21 -17.55 -179.09 537 7.20 MwHRV ..FG .......
PDE 1998 04 01 175623.36 -0.54 99.26 55 7.00 MwHRV .FFG .......
PDE 1998 05 03 233021.91 22.31 125.31 33 7.90 MEGS 5FFG .T.....
PDE 1998 05 21 053425.50 0.21 119.58 33 7.20 MEGS .FFG .......
PDE 1998 05 30 062228.95 37.11 70.11 33 7.00 MEGS .CFG .......
PDE 1998 07 16 115636.42 -11.04 166.16 110 7.00 MwGS ..FG .......
PDE 1998 07 17 084913.28 -2.96 141.93 10 7.10 Ms GS .CFG .T.....