(Adds details on the quake, U.S. geological survey data)
MANAGUA, April 14 (Reuters) - A third earthquake in less than a week struck Nicaragua early on Monday morning, shaking buildings in the capital, Managua, though there were no immediate reports of damage.
An official at Nicaragua's seismological authority said the quake magnitude was 5.6, but its shallow depth had imparted a greater impact.
The U.S. Geological Survey (USGS) said the quake struck some 6 km (4 miles) northwest of Managua at a depth of 14 km. The USGS initially registered the quake at magnitude 5.1.
Emergency services in Managua were checking for signs of impact, but did not immediately report any damage.
Earthquakes also struck Nicaragua on Thursday and Friday last week. The latter, of magnitude 6.6, was felt as far away as El Salvador and Costa Rica. (Reporting by Ivan Castro; Editing by Clarence Fernandez)