Water is slightly more dense than ice so man-made reservoirs must have the same effect. We should build more dams in California. By shifting water between two reservoirs it is likely possible to massage out near-surface earthquake tension completely.
Except that reservoirs are a fairly small footprint over a faultline, whereas an icesheet can cover thousands or millions of square miles.
I don’t know if it’s true or not, but the Oroville, California, earthquake of the early 1970s was suggested to have been caused by the building of the dam there.
My guess is that it’s more likely to have been a coincidence, but I’m not sure we could ever know.