Greek authorities were put on alert on Saturday for the next two days after a 6.2-degree earthquake on the Richter scale jolted the southern Aegean Sea island of Crete. The strong tremor which hit in early afternoon and was felt in Athens and other areas up to 300 kilometers from its epicenter off the western coast of Crete, caused minor material damages, but no injuries, according to local officials. An elderly man jumped off a first floor balcony, but was not injured, local media reported, as the General Secretariat for Civil Protection was gathering data on the impact on buildings and infrastructure. \"We acted quickly on calls for a few small rocks which had fallen in regional roads in mountainous areas and minor damages at old houses. So far we do not face any major problems, but we have instructed people to be on alert, as we are,\" Tassos Kouroupakis, head of the Civil Protection mechanism at the city of Chania told Xinhua. All authorities across Crete remain on alert, Deputy Governor of Crete Apostolos Voulgarakis said, as life returns to normal. Locals and foreign tourists are still quite anxious, as more than a dozen aftershocks measuring up to 4 degrees on the Richter scale have occurred after the big earthquake which struck at 16:12 p.m. local hour. Greek seismologists speaking to Xinhua assure that there is \"no reason of great concern.\" Crete, as entire Greece, is a seismic prone zone and increased seismic activity decreases concern. However, they can still not make any conclusions whether this was the main tremor and therefore suggest caution. \"We will have to wait and see what happens over a 48-hour course. It has been proved that if nothing big happens within the first two days after a big tremor, there is about 85 percent possibility that this was the main quake,\" Professor Costas Makropoulos, Director of the Geodynamic Institute of the Athens National Observatory said. He noted that the area in which the earthquake\'s epicenter is located (about 70 kilometers off the western coasts of Crete at 23 kilometers depth) is known for its seismic activity. In 365 A.D., an 8.3-magnitude quake on the Richter scale, according to estimates based on historians\' descriptions, caused a destructive tsunami, Makropoulos said speaking in Greek media. Over the past six decades at least three strong earthquakes measuring more than 6 degrees on the Richter scale and dozens smaller ones have been recorded. Geological Institutes across the globe on Saturday gave higher measurements of up to 6.5 degrees on the Richter scale for the quake, but Makropoulos and his colleagues insisted on the 6.2 estimate. \"I can\'t say how big it was, as experts, but it felt terrible. I know that I will not be feeling very comfortable sleeping at my bed tonight and for several days after this,\" local resident Patricia Massauraki told Xinhua. She was among hundreds of people who rushed outside their homes when the quake hit. She still remembers the 1999 quake of 6 degrees on the Richter scale in Athens which left behind more than 100 casualties and extensive material damage. Greece is one of the world\'s most quake-prone countries and is often jolted by tremors. The 1999 quake was the most recent biggest tragedy caused by a quake in Greece.