A swarm of small earthquakes jolted San Ramon over the last month. Scientists said the earthquakes are normal and aren’t indicative of the big one.

The clusters of earthquakes have all been underneath the East Bay suburb of San Ramon, which is close to the Calaveras fault. There were at least 19 earthquakes of magnitude 2 or greater on Monday alone.

A swarm of at least six earthquakes reaching up to magnitude 2.9 rattled San Ramon near San Francisco, the U.S. Geological Survey reports.