A Magnitude 6.7 was recorded in Greece at 12.30 pm local time today. At this time no injuries or damages are reported.
Here is some initial data.
Wednesday, July 01, 2009 at 09:30:12 UTC
Wednesday, July 01, 2009 at 12:30:12 PM at epicenter
Time of Earthquake in other Time Zones
38 km (23.6 miles)
130 km (80 miles) S of Iraklion, Crete, Greece
195 km (120 miles) SE of Chania, Crete, Greece
270 km (165 miles) NNE of Tubruq, Libya
450 km (280 miles) SSE of ATHENS, Greece
horizontal +/- 7.1 km (4.4 miles); depth +/- 12.8 km (8.0 miles)
NST= 51, Nph= 51, Dmin=131.6 km, Rmss=1.19 sec, Gp= 72°,
M-type=teleseismic moment magnitude (Mw), Version=7
USGS NEIC (WDCS-D)
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Updates received about earthquakes in Greece from our archive
As been mentioned Crete is an ‘active’ area with small earthquakes every year. The last significant earthquake was about 5 years ago , 6,3R as I remember. I was standing on my patio at the time and suddenly instead of standing on concrete I felt that I had jumped onto a bed. I had water in bowls (for the cats) and this started sloshing from side to side, spilling out of the bowls. A little later I visited an office on the 5th floor of a block in Chania where there was a free standing iron decorative stand against a wall and I could see marks on the wall where it had swayed from side to side about 10cm or so. However, there were no reports of severe structural damage, just odd bricks and tiles in the road from the tops of old buildings, and a few old garden walls down. I remember at the time feeling that there was less damage than happened a few years previously in England when there was a hurricane.
One must remember that the Richter scale is based upon energy released and this is not always a good indication of ‘effect’. An structural engineer friend said that the Turkish eathquake was very long in duration as these things go although the R value was not too high. The earthquake in Athens was only 5.9 but it was very fast moving which exagerated its impact.
The building regulations in Greece are very strict with respect to Earthquake resistance: Accoring to my friend amongst the most stringent in the world. To obtain planning permission you must supply a complete structural ‘static’ analysis of the foundations and skeleton to show that it will withstand earthquakes. All factors are specified in the plans, the sizes of columns etc, the steel and Grade of concrete are all specified. The problem is that the building must be constructed according to the design and with good building practices. For instance the owner, or the builder may decide to save money by perhaps using less steel or by using a lower strength grade of cement, or may not excavate enough to ensure solid foundations. The builder may add water to the specified mix of concrete to make it easier to work, he may not place the steel correctly within the concrete formwork, he may not ‘cure’ the cement properly (keeping it wet during the setting time, perhaps 5 days). These things should be checked by the engineer responsible for the building, but … I believe that in Athens the Architects/Engineers and builders responsible for the construction of the buildings that collapsed are currently being sought. Perhaps we shall learn more.
Of course quite a number of people decide to build without obtaining planning permission, but that’s another story. Another problem, particularly with commercial buildings, is that the owners may decide to modify them when business need change, perhaps without consulting an Engineer to question the impact of the changes. With respect to the steel often seen protruding from the tops of buildings, as I think someone else has said, the Greeks are very family oritented, when they build they do often plan for further stories for their children eventually. If they can afford it they build beforehand and rent-out the upper floors, always intending their children to eventually live there. Well built old houses often resist earthquakes but in a completely different way than new buildings. Problems arise when they are not properly maintained or are ‘renovated’ in a ‘modern’ way using large quantities of concrete which tends to work against their intrinsic resistance modes.”
Most of them aren’t even noticed, some are strong, but since they happen far below sea level, no damage is done to the surface, apart from maybe an old building partially collapsing. Since some decades the Greek government has issued severe earthquake building regulations, which are served everywhere. All buildings should be made out of armoured concrete, to survive a ‘normal’ earthquake of 7 on Richter’s scale.