Five earthquakes were registered in Bulgaria in the time span of five hours.

The first tremor, measuring 4.2 on the Richter scale occurred at 10am, representatives of the geophysical institute of the Bulgarian Academy of Sciences said. The epicenter of the earthquake was located 240 km south of Sofia, Novinar newspaper reported.

Less than 30 minutes later a second earthquake occurred closer to the capital. Its epicenter was located 55 km away from Sofia, close to Kalotina border checkpoint.

At noon another tremor occurred in the Sliven region. The fourth quake occurred at 2pm but was much weaker than the previous tremors.

A final earthquake occurred in the afternoon, once again in the Sliven region.

Seismologists predicted in the end of April such earthquakes could take place. Because of the predictions representatives of the Disaster Management Ministry are working on a warning system.