The quake was of long duration, perhaps as much as 30 seconds. The quake was felt strongly all over the country. Lesser quakes followed. There were no initial reports of serious damage.
The estimate of a magnitude by the U.S. National Earthquake center was 7.6. That agency said the quake was just 41 kilometers deep, some 25.4 miles. Shallower quakes generally cause more earth movement on the surface.
Some communications failed in the Central Valley, perhaps due to thousands of persons being on cellphones and land lines.
The U.S. center said the epicenter was 53 kilometers (95 miles) west of San José.
There were reports of some damage even in the Central Valley where many homes suffered at least falling objects. There were reports of trees falling elsewhere.
Initial reports from the Nicoya peninsula were delayed due to communication failure. There were some reports of small landslides.
Tsunami warnings were posted briefly for areas along the Pacific then withdrawn.