Following Tomas post let’s stay a little longer on the Corinth Canal. The 6 km long famous Corinth Canal despite being an amazing feat of engineering, since it was constructed 120 year ago, it’s also a geology field trip favourite because it is basically a MEGA TRENCH.
More than 40 faults can be identified some of them offsetting the entire sedimentary column, whereas others are confined within the lower sediments. Therefore, this photo shows a very nice example of an active and inactive fault within the same outcrop. You can rarely see something like that and this is a unique site where everybody can see and comprehend it.
View of an active and inactive fault
Faults also die.
It shows also that faults die. This is very important because there are numerous faults in the crust, however the majority of them are inactive (e.g. can not give an earthquake today, but they did so in the past). So for earthquake geologists their first major goal is to identify which of the faults they map are active (e.g. can generate earthquakes today and represent seismic sources).
Faults also die.
Today’s Friday links concentrate on tsunamis. Recently, Pure and Applied Geophysics came up with quite a lot of tsunami papers, and I am sure that this decision was made before the Japan tsunami happened. Some papers fur sure are interesting for analysing past tsunamis and earthquake environmental effects.
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While the Japan earthquake has dominated the media obviously, some other news came up in geoscience. A researcher team lead by Ludovic Ferrierè who works at the Natural History Museum in Vienna claims to have proven the first impact crater in central Africa. The Luizi structure in the Democratic Republic of Congo was described in 1919 by a German study, but has not been confirmed as an impact crater for decades. Ferrierè and his team now found shatter cones and shocked quartzes, strongly pointing to an impact. The crater has a diameter of 17 km and a 350 m high rim, which led the scientists to assume a meteor of 1 km diameter and a velocity of ~20,000 m/s. more
The Christchurch earthquake was the main topic of the Geoblogosphere this week. A great analysis on the effects was provided by Dave Petley in his Landslide Blog. Highly Allochthonous reasoned on seismic lensing, Ontario Geofish posted a lot on building security, and countless news sites came up with photos and reports. Frank Taylor, who hosted the GoogleEarthBlog before he left for a sailing trip around the world, was in Christchurch next to the Cathedral when the quake happened. On his Tahina Expedition website he reports on his experiences.
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Today on Friday, 11 February, a magnitude 7.0 earthquake occurred offshore in Chile near Concepcion at 36.5° S and 73° W in a depth of 28km. The MMI at the nearby large cities was reported by the USGS with V.
Update: The magnitude was corrected to 6.8. The earthquake was followed one hour later by a further event with a magnitude of 5.3 and 4 hours later again by a more shallow 6.3.
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The Accredtionary Wedge #30 blog carnival hosted by Mountain Beltway came up with a tasting idea in January: The Geological Bake Sale. Explore and enjoy thematic food like the moon surface cake, the pillow lava bread and the debris flow vegetables. If you create a sweet fault or a tasty trench, we promise to publish it on paleoseismicity.org. more
The California Geological Survey provides a great online-tool for geoscientist: A fault map of California (Alquist-Priolo-Fault-Zone with all datasets available in PDF and GIS format for free! Start here.
A volunteer panel that assesses earthquake risks in Utah said it examined nearly 130 school buildings in the state and found more than half fail to meet federal earthquake safety guidelines. Bad news from here.
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The L’Aquila earthquake from 6 April, 2009 caused more than 308 fatalities and destroyed about 15,000 buildings. A new initiative set up by the British architect Barnaby Gunning aims on creating a 3D model of the destroyed city in its present state with SketchUp for GoogleEarth. The model will be used for “creating a valuable resourcef for masterplanning the reconstruction”, Gunning states on the project’s homepage. more
On Wednesday night the Etna on Sicily showed strombolian activity and glowing lava flows were visible from Catania. Don’t miss the great photos here and the webcam of the INGV and EtnaTrekking. This is the first larger eruption since May 2008 and surely one of the most beautiful ones. News coverage with more great videos here.
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