Christoph Grützner

Today’s Friday links are mostly about cake geology and scientists playing with food, but let’s start with something different. Yesterday, volcano Fuego (“fire”) erupted in Guatemala and produced an impressive column of ash and smoke. This beautiful stratovolcano is only 40 km from Guatemala City and one of the most active volcanos of Central America. more

The Sparta Fault in Greece is marked by one of the most impressive mountain fronts I’ve ever seen. A huge (yes, huge!) fault scarp has developed, traceable for kilometers; the fault itself is more than 60 km long. Ancient Sparta has been devastated by the last known major (M>7) earthquake that happened at this fault in 464 BC. Now, Papanikolaou et al. have published new data on this fault. They examined how paramaters like throw, segmentation, and catchments vary along strike and created a new seismic hazard map, showing a site-specific long-term recurrence interval of ~1.8 ka (+/- 450 a). more

A new paper has been published online first by Hinzen et al. on their archeoseismological study in Cologne, Germany. During recent archeological excavations, a number of damaged structures from Roman to Medieval times have been discovered and described among them a synagoge, the Praetorium, and a Roman well. Since damaging historical earthquakes are documented for the Lower Rhine Embayment, seismic shaking was a good guess to have caused the observed damage. more

Two really strong earthquakes happened yesterday at the Mid-Atlantic Ridge in the Jan Mayen Islands area. The first one had a magnitude of M6.6, the second one, around ten minutes later, had M5.3. Moment tensor solutions show clear strike slip along a transform fault west of the ridge. The seismicity map shows that events like yesterday’s don’t come as a suprise: more

One of the coolest things I recently read about was the Syracuse University Lava Project. I mean, how cool is it to produce your own lava at 1200°C and to let it flow on Campus? Pretty cool. And, as you can see on these images, it is a great way to teach children how cool geoscience is. Watch the beautiful structures developing when the lava cools down: more

A new earthquake catalogue has been published by the GFZ Potsdam (German Research Centre for Geosciences). The Database covers the European-Mediterranean area and reaches back to AD1000. This is good news and an important step on our long way to collect all earthquake information available in one place. I say it’s a first step only, because we know much more than the catalogue incorporates: Besides ~100 years of instrumental records we have historical data covering hundreds of years in many regions, but reaching back to some thousands of years in regions like Greece and Israel. Then, there’s archaeoseismological data of course and paleoseismology, which can resolve events that happened thousands of years ago. more

This morning at 03:00 UTC an earthquake with magnitude M_W7.7 occurred in the Sea of Okhotsk. Due to its great depth of more than 600 km no tsunami was triggered and surface shaking was pretty low, however, the event was felt in a wide area. Moment tensor solutions indicate a thrust event. Historical seismicity tells us that significant earthquakes are likely to happen in the region and mostly occur in great depths, but at this certain location only few events have been registered during the last decades. more

After I came back from one week of holidays I checked the latest papers. Surprisingly, one was by myself! Finally IOP published our work on combined geoscience techniques in the Orkhon Valley, Central Mongolia. We used Georadar, SQUID-gradiometers, capacitive-coupled geoelectrics, octocopter stereoimages, shallow drillings, datings, and archaeological excavations for an geoarchaeological project. Using geophysical, archaeological and geological observations, we assumed a dating in the Turk/Uighur period (6th–9th century AD) and a re-use under Mongolian reign (12th–17th century AD). This would mean that this site is the furthermost walled structure in the peri-urban area of Khar Balgas. more

Although I already recommended some papers earlier this week, I have two more to mention: Supawit Yawsangratt and colleagues published new data on “Evidence of probable paleotsunami deposits on Kho Khao Island, Phang Nga Province, Thailand”. Nat Hazards, 63,151-163, DOI 10.1007/s11069-011-9729-4 in a special issue dedicated to tsunami research. Ran et al. presented work on the Wenchuan EQ epicentral area: “Paleoseismic events and recurrence interval along the Beichuan -Yingxiu fault of Longmenshan fault zone, Yingxiu, Sichuan, China.” Tectonophysics (2012), doi: 10.1016/j.tecto.2012.07.013. more

Currently I spend my time working on some papers that deal with tsunamis in the Eastern Mediterranean and earthquakes in Spain. Searching for literature and looking for data on the Minoan catastrophe I came across this new open access publication by Simon Jusseret and Manuel Sintubin:

• All That Rubble Leads to Trouble: Reassessing the Seismological Value of Archaeological Destruction Layers in Minoan Crete and Beyond. Seismological Research Letters, 83, 4, 736-742, doi:10.1785/0220120011.

Our colleagues from IGCP567 – Earthquake Archaeology put a lot of effort into getting rid of catastrophism and into making archeoseismology a more reliable, quantitative science. By the way, don’t miss the next workshop on archeoseismology and active tectonics in Mexico 2012! more