Active and Inactive Faults

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
View of an active and inactive fault
Faults also die.
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.

New paper on the paleoseismicity of the Dead Sea – Kagan et al., 2011

Some days ago a new paper on the paleoseismicity of the Dead Sea area during the late Holocene has been published in JGR. Kagan et al, 2011 investigated two new study sites in the northern and southern parts of the Dead Sea Basin and compared the seismites found there with the information of the Ein Gedi core presented by Migowski et al., 2004.

Continue reading “New paper on the paleoseismicity of the Dead Sea – Kagan et al., 2011”

The Wednesday Centerfault (1)

It’s not easy to prepare weekly Friday links when you are abroad, this is what I had to realize in April. However, I will try to post a natural beauty each Wednesday in the future, the Wednesday Centerfaults and Centerfolds.

Today, I start with the Kaparelli Fault in Greece (38.22°N, 23.23°E). This beautiful limestone fault scarp is more than 2.5 km long and up to 5 m high. The fault was activated during the 1981 Corinth earthquakes. Continue reading “The Wednesday Centerfault (1)”

New paper: Alsop & Marco: Soft-Sediment deformation within seismogenic slumps of the Dead Sea Basin

Some days ago, a great new paper was published on the investigation of soft-sediment deformation in paleoseismology: “Alsop & Marco 2011: Soft-Sediment deformation within seismogenic slumps of the Dead Sea Basin. Journal of Structural Geology 33 (2011) 433-457.” The authors investigated the most beautiful seismites I’ve ever seen and generated different scenarios for their interpretation with respect to paleoseismic events. Continue reading “New paper: Alsop & Marco: Soft-Sediment deformation within seismogenic slumps of the Dead Sea Basin”

Paleoseismicity at the EGU2011

Now the EGU2011 in Vienna is over. Thousands of scientists have attended the meeting and more than 13,000 abstratcs were presented. Approx. 20,000 portions of Gulasz and 100,000 Wiener Schnitzels were served, hektoliters of wine and beer went down the throats of thirsty scientists. Some people say the EGU contributes with 10% to the income of Vienna’s bartenders. Several contributions dealt with paleoseismology, paleoseismicity, archeoseismology and paleotsunamis especially on Monday and Friday. Continue reading “Paleoseismicity at the EGU2011”

Japan earthquake aftermath – blogs and press

The Japan earthquake and tsunami have hit Japan harder than we could have imagined. Thousands are still missing, the death toll climbs and climbs, a nuclear disaster might happen or already happened, depending on who you ask, and the economical damages are incredibly high. Not only Japan was affected, but other countries as well feel the effects. Germany, for example, shut down seven of it’s oldest nuclear power plants and there’s a big debate on earthquakes and risks. The Geoblogosphere is still discussing lessons, estimations and consequences, and so are the official media. Here are some reports and opinions you should not miss. Continue reading “Japan earthquake aftermath – blogs and press”

Japan EQ & Tsunami: Environmental Effects

The Japan M9.0 earthquake and the following tsunami are well documented by videos, photographs, sea-level measurements, seismograms etc. But how do we recognize such huge events if they happened some thousands of years ago? If there’s no historical report we would use earthquake environmental effects (EEE) for characterizing the earthquake and paleoseismicity. Let’s look what would be left from a 5000 year old earthquake and tsunami. Continue reading “Japan EQ & Tsunami: Environmental Effects”

Mw9.0 earthquake hits Japan, causes Tsunami (updated – 3)

An earthquake with a magnitude of Mw9.0 has occured 130 km east of Honshu, Japan in a depth of ~25 km. This had been the fourth or fifth strongest earthquake to be recorded by instrumental seismology. The quake caused significant destruction to the Honshu Island and triggered a tsunami that  destroyed a number of harbours. In some places (Sendai), tsunami heights were reported to exceed 10 m. A tsunami warning has been released for wide parts of the Pacific, but in Hawaii only 1 m was observed, therefore the warnings for the US West Coast have been lowered. Continue reading “Mw9.0 earthquake hits Japan, causes Tsunami (updated – 3)”

What’s up? The Friday links (8)

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.

Continue reading “What’s up? The Friday links (8)”

Why was the Christchurch earthquake so devastating?

A M6.3 earthquake hit Christchurch, New Zealand on 22 February (21 Feb in UTC), leaving at least 75 people dead and hundreds injured or missing. Hundreds of houses were destroyed, including the Christchurch Cathedral, and damages will probably sum up to some billion dollars. On 4 September 2010 (3 Sept in UTC), a M7.0 event struck Christchurch, but then no one was killed. So: what’s the difference between the two events?

Continue reading “Why was the Christchurch earthquake so devastating?”