The idea that global warming might trigger earthquakes in some regions is not ridiculous, the mechanism would be the reduction of the weight of the ice sheet above certain landmasses. Antarctica and Greenland in particular, but maybe also some mountain ranges. Most of the articles I can find on this go back to work by Bill McGuire of UCL, sometime director of the Benfield UCL Hazard Research Centre. It is also he and his students or postdocs (Simon Day and Stephen Ward) who are responsible for the idea that the Western side of La Palma might slide into the sea, causing a "megatsunami" which might devastate the eastern seaboard of North America.

Bill McGuire is a credible scientist, and his analysis of the impacts of various natural phenomena is usually pretty good. What often gets lost though when this research gets reported in the popular press is the incredibly low probabilities of these events.

As far as "absence of evidence is not evidence of absence", well if both evidence and a mechanism are absent then its pretty clear that its something which you don't have to worry about too much. Bill McGuire to be fair does propose mechanisms, and then when you understand what the mechanism is you can work out the probability of it occurring.