I've read here(HN) in the past that fracking hotspots caused "earthquakes" somewhere in europe, is it debunked or non issue?

In addition I've read/heard that Ormat which manages/builds many such small plants that they pump a different fluid(not water) in the pipe to extract the heat to create power [as opposed to what is stated in the article and in comments here] https://patents.google.com/patent/CN101142377B/en