
The Swiss closed their enhanced geothermal project because it was causing damaging earthquakes. The Feds pulled the plug on a California project because of repeated problems like drill bits snapping off as well as concerns about the Basel earthquakes.
The type of geothermal energy explored in Basel and at the Geysers requires fracturing the bedrock then circulating water through the cracks to produce steam. By its nature, fracturing creates earthquakes, though most of them are small.
“Most”?
Geothermal has huge potential. However, geothermal methods do not usually require such deep drilling or fracturing bedrock. Any geothermal method that causes earthquakes needs to be avoided. Period.