On 15 October, 2013 a shallow Mw7.1 earthquake occured in Bohol, Philippines. The quake caused more than 200 fatalities and severe damages. Instrumental intensities of VIII – IX were recorded and the USGS estimates the maximum slip to be around 120 cm. Stéphane Baize from the French IRSN created a report not only on the seismological and tectonic background of the earthquake, but also on the earthquake environmental effects (EEEs) that were caused by the event. more
A fascinating series of relatively shallow minor earthquakes is currently occuring in Romania in the Galaţi area. Around 40 events occured during the last few days, most of them with magnitudes of ~3. Now a mb5.4 earthquake happened in more than 100 km depth. The quake was felt in wide parts of Romania and Bulgaria. Due to its depth no damages are expected. First moment tensor solutions do not give a clear picture yet, but it seems like NE-SW trending thrust event could have happened at the SE bend of the Carpatian Mountains. more
After the strong earthquake in Pakistan a good part of the media coverage was about the fascinating story of the new island that emerged off Gwadar. While this was really amazing I think now it’s time to think about the consequences of the quake itself. We have seen a shallow M7.7 event that produced severe shaking across a large area. Peak ground acceleration exceeded 1 g in the 0.3 s period and was still intense in longer periods. 515 people have reportedly been killed and more than 100,000 are homeless. more
It’s time to revive the Friday Links tradition, I just realized that it fell asleep in March…
A paper published in Science few hours ago deals with the energy release of one of the strangest mega-quakes that we have ever observed, the M8.3 Okhotsk event of 24 May 2013. The interesting thing is that is occurred in more than 600 km depth! In the same issue of the journal another paper describes attempts to perform analogue experiments of such events in the lab. If you just want to get a rough idea about the studies or have no access to science, I recommend to check out Andrew Alden’s article at kqed science. more
Todays field work image is again by Elisa Kagan and shows a damaged stalagmite in the Soreq Cave near Jerusalem. Damaged stalagmites were used to reconstruct earthquake recurrence intervals. more
The latest issue of the Seismological Research Letters (SRL) does not only have a very stylish cover, but also includes some papers that will be of interest for the fans of old earthquakes and environmental earthquake effects (EEEs). In the Historical Seismologist section, Bilham et al describe the hunt for a lost fault – that is, one that was described by Oldham in the 19th Century, but never really located and almost forgotten. Nice! more
I am currently in Greece for field work on faults in the vicinity of Athens. Sascha from RWTH Aachen University is doing his MSc. thesis on remote sensing, geophysical analyses, and mapping of some structures that we think could be active, and me and Ioannis are with him in the field for the first few days. Right on the first day we found some promising outcrops which we will map and check in detail during the next days. more
The latest issue (May 2013) of the Bulletin of the Seismological Society of America (BSSA) is dedicated to the Tohoku Earthquake and Tsunami of March 2011. The studies published therein deal with the source models of the megaquake and rupture dynamics, the ground motions, the tsunami propagation, earthquake triggered landslides and induced seismicity, earthquake environmental effects, and one paper presents a new proposal for an extended Tsunami Intensity scale. more
Last night (22:29 UTC on 22 April) a M4.5 earthquake rattled NE Hungary. The event was shallow (~10 km) and the epicentre was only about 25 km south of the city of Eger, famous for its red wine (Egri bikavér). The area is south to the Inner Western Carpathian Mountains. Light damage has been reported from the epicentral area, the EMSC questionnaires document intensities of VI. more
A very strong earthquake occurred in Eastern Iran close to the Iran-Pakistan border. USGS reports a magnitude of 7.8 and a shallow depth of 15 km, EMSC data suggest M7.7 and 50 km depth. Preliminary shake maps estimate intensities around MSK VIII, which would be enough to make traditional adobe buildings to collapse. Reports confirm the event was felt as far away as Muscat, Oman (600 km distance!). Update: USGS now also reports a depth of 80 km.
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