Costa Rican officials urged citizens to avoid clogging the emergency lines by not calling 911 unless it was to give information about an urgent situation. It did not trigger a tsunami threat in the Pacific.
The quake hit 294km southeast of the city of Kamaishi at a depth of 9.5km.
Firefighters in Jaco said there were no reports of victims or major damage, but said there were some electrical poles that had come loose and fallen.
The USGS originally measured the earthquake-which struck at a depth of six miles-at a magnitude of 6.8 but later downgraded it. It also showed images of alarmed people running in a supermarket as products fell to the ground.
Neighboring El Salvador's civil protection agency tweeted that the quake caused some electrical posts to fall, while the civil protection agency in neighbouring Panama said there were no reports of damage there.
Rescue workers remain outside the Monsenor Sanabria hospital in Puntarenas, 90 kilometers (56 miles) northwest of San Jose, Costa Rica on September 5, 2012, after a powerful 7.6-magnitude quake struck the country.