THE GEYSERS, Calif. (AP) — Seismologists have canceled a report of a magnitude-4.0 earthquake in Northern California after a review of the data.

Seismologist Susan Potter says a preliminary report from the U.S. Geological survey showed that a quake struck about 25 miles north of Santa Rosa in the hour after a much larger quake shook Mexico and Southern California, but the report was deleted hours later.

It was not immediately clear why the false report was generated, but large temblors can often produce faulty readings in distant areas.

Potter says a swarm of small earthquakes has shaken the area, but none have been larger than magnitude-2.3.