On 12 June, 2017, an earthquake with a magnitude of Mw6.3 occurred south of the island of Lesvos in Greece, damaged hundreds of buildings and claimed one life. The event ruptured a NW-SE trending normal fault and had a focal depth of 13 km. Our colleagues from the National and Kapodistrian University of Athens mapped the earthquake damage and the environmental effects that accompanied the earthquake. They found mass movements, secondary cracks, and report on a small tsunami. Their report can be downloaded here (PDF, 6 mb). For a higher-resolution file (33 mb), follow this link. Many thanks to Efthymios Lekkas for sending the report. Continue reading “Preliminary report on the 12 June, 2017, Lesvos (Greece) Earthquake”
A special session on Toppled and Rotated Objects in Recent, Historic, and Prehistoric Earthquakes will be held during the upcoming 2017 Annual Meeting of the Seismological Society of America in Denver, Colorado from 18-20 April 2017. Session Chairs will be Klaus-G. Hinzen and Rasool Anooshehpoor.
The main purpose of the session is to bring together researchers with diverse backgrounds (e.g., seismology, engineering, history, heritage conservation) who are interested in the behavior of objects, monuments, or simple structures during earthquakes and the stories which deformed, rotated or toppled objects can tell. The session will cover all aspects of toppled or rotated objects or simple structures which have suffered heavy deformation or damage during earthquakes. Topics will include: (1) observations, (2) documentation, (3) model building, (4) restoration, (5) mapping, and (6) correlation with geology.
Recent earthquake research has postulated correlation between the reaction of objects (monuments, columns, tombstones, etc.) and the seismic source in addition to local effects due to geological site conditions. As the laws of physics are time invariant, knowledge gained in reconnaissance surveys from well-studied instrumental earthquakes can reveal information about ground motions during historical and prehistorical earthquakes. Particular interest will be directed to man-made structures; however, due to similarities of the techniques used to study precariously balanced rocks and speleothems, contributions from these fields are also welcome.
The deadline for all proposed presentations, invited or otherwise, is 5 pm PST January 11, 2016. All abstracts must be submitted by the deadline. Submitting abstracts through the online submission system only (There is a submission fee of $80 for regular attendees, $40 for students).
There are lots of other interesting sessions on earthquake geology, paleoseismology and related topics at the SSA meeting, make sure to check the full programme: http://meetings.seismosoc.org/special-sessions/
Annals of Geophysics has just published a special issue on the devastating Amatrice Earthquake series in Central Italy: Vol 59, Fast Track 5 (2016): The Amatrice seismic sequence: preliminary data and results.
The special issue, edited by Marco Anzidei and Silvia Pondrelli, contains lots of field reports, first assessments, and plenty of primary data. Plus, it’s all OPEN ACCESS! Continue reading “Special Issue in Annals of Geophysics on the Amatrice earthquakes”
The M7.8 Kaikoura Earthquake in New Zealand produced one of the most complex ruptures ever observed, involving many different faults. Earthquake environmental effects include up to 10 m offset at the Kekerengu Fault, secondary ruptures, a tsunami, coseismic uplift, landslides and rockfalls, liquefaction, and maybe even earthquake lights. Lots of blogs and websites provide coverage on this earthquake, e.g. Geonet, the Landslide Blog, and The Trembling Earth. Our colleagues from the Research Group on Earthquake Geology in Greece worked on the landslides that happened during the earthquake. George Papathanassiou sent me the link to their Preliminary Map of Co-Seismic Landslides for the M 7.8 Kaikoura, New Zealand Earthquake. Continue reading “Preliminary Map of Co-Seismic Landslides for the M 7.8 Kaikoura, New Zealand Earthquake”
On 26 October two shallow normal faulting earthquakes occurred in Central Italy, very close to the epicentre of the Amatrice Earthquake from earlier this year. The first quake reached a magnitude of M5.5 and was followed by a M6.1 just two hours later. The events caused serious damage (see here for a video and some images), but luckily only one person died as most people had left their houses after the first moderate shock. This could have turned out much worse. Apparently the quakes at least partly filled the gap between the 1997 Colfiorito events and the 2016 Amatrice Earthquake. Continue reading “Earthquakes in Italy: first InSAR data and field reconnaissance”
Our colleagues Stéphane Baize and Oona Scotti from the French IRSN finished a report on the 2014 Napa Earthquake: Post-seismic survey report, with special focus on surface faulting. On 24 August 2014, an earthquake of magnitude Mw6 occurred on the West Napa Fault in shallow depth. The quake caused significant damage, an interesting pattern of surface ruptures, and the immediate attention of hundreds of geologists. The primary and secondary effects were mapped only hours after the event, which turned out to be extremely important – a large amount of afterslip was recorded in the following days. The earthquake was not only recorded by a huge seismometer network, but the ground motion was also captured by GPS sensors and InSAR images. The new IRSN report is especially concerned with the surface faulting hazard, since this agency is responsible for the safety of nuclear installations in France. Continue reading “IRSN report on the Napa Earthquake, California (M6, 2014-08-24)”
I am running this blog for more than five years now and it is time to acknowledge the other geo-blogs out there that have inspired me. In order to stay updated I follow the Geobulletin, which monitors the geoblogosphere activity. There are numerous amazing blogs out there that are either fun to read or interesting or both, but here I will focus on the ones dealing with earthquakes/tectonics/geomorphology/tsunamis. Here is my personal, subjective, but honest, list of earthquake blogs that I like and read: Continue reading “My top ten list of earthquake blogs”
Our colleague Efthymios Lekkas kindly uploaded a new report on the recent South Lefkada Earthquake. If you can read Greek, have a look at this website: http://www.edcm.edu.gr/. Alternatively, you can download the slideshow from his personal website here as a PDF: http://www.elekkas.gr/images/stories/Frontpage/2015_Lefkada/lefkada2015.pdf
The PDF contains info on the tectonic setting, historical and instrumental seismicity, followed by a collection of the earthquake (environmental) effects. Continue reading “New data on the 17 Nov, 2015, M6.4 South Lefkada earthquake”
On 17 November, 2015, a MW6.4 strike-slip earthquake occurred in Lefkada Island, Greece. Lefkada is close to the Cephalonia Transform Fault and has repeatedly experienced strong shaking in the past. The most recent event caused two fatalitites, some damage, and resulted in widespread environmental earthquake effects (EEE). A team of scientists visited the epicentral area after the quake and recorded the damage and the EEEs. They wrote a preliminary report, which can be downloaded here: Lefkada 17 Nov 2015 earthquake report (PDF, 3.9MB).
They document mass movements, damage to buildings, and present first data from seismology, GPS and satellite geodesy.
Thanks to George for sending us the report!
We published a new study dealing with paleoseismological work on the Milesi Fault near Athens, Greece. A slip rate was estimated based on GIS work, mapping, and trenching. Four surface-rupturing earthquakes in the last 4-6 ka were found, and we estimate magnitudes of around M6.2. With these input parameters, we developed a seismic hazard scenario that also takes into account site effects. Our results show that the official seismic hazard zonation in Greece, which is based on instrumental and historical records, contradicts geological data. We also show that extension in this region is not only confined to the Southern Evoikos Gulf graben system, but a significant amount of extension is accommodated by active faults closer to Athens. Continue reading “New Paper: Paleoseismology & active tectonics in Greece, and how seismic hazard zonation fails”