Some readers reacted with outrage, and others more mildly, after I reported in The Times on Wednesday that a geothermal energy project north of San Francisco is likely to generate earthquakes.

The project, by a start-up called AltaRock Energy (which itself responds to the Times article here), is on the site of a huge existing geothermal project that extracts steam from steam beds at The Geysers, a mountainous area underlain by deep, upwelling magma. The steam circulates through natural cracks in a shallow layer of sandstone-like material; the AltaRock project will, for the first time, drill much deeper and fracture a hard, granite-like rock that caps the magma in an effort to extract more energy.

Seismologists agree that the new operation, like the existing one, will generate at least small earthquakes. Scientists are much less certain of whether the company can, as it claims, be sure that it will not set off larger quakes.

“Brilliant — the first major geothermal project in the United States smack in the middle of the most active seismic zone in the country,” wrote one reader, who identified himself as Stephen Reichard of Portland.

That thought was expressed in one way or another by numerous readers, who wondered why the technique could not be tried in a more remote area that is not already plagued with earthquakes. Perhaps counterintuitively, the company has said that it picked The Geysers precisely because the many earthquakes there suggest that no surprises (such as a major, undiscovered fault) will turn up.

But others pointed out that every energy source has downsides, and noted that geothermal energy will help cut the country’s dependence on fossil fuels.

“So what if it causes some earthquakes? That’s still far less dangerous then coal, which causes massive health and environmental problems,” wrote Brendan Miller of Seattle. “Think about how many people get cancer from coal.”

Still others, especially on the West Coast, could not take seriously the magnitude 3.4 quake set off by a similar project in Basel, Switzerland.

“People freaked out over a 3.4 quake?” wrote Sarah of Sunnyvale, Calif. “Sheesh, that’s a baby quake.”