Some weeks ago we published a new study on the classification of earthquake-induced landslide event sizes based on seismotectonic, topographic, climatic and geologic factors. Our idea was that this classification could be used to help improve seismic hazard assessment by contributing to a better prediction of landslide hazards induced by an earthquake when the geologic, topographic and climatic context is well defined. Possible applications could be the short-term prediction right after an earthquake or scenario modeling, e.g. for critical infrastructure. Since earthquake triggered landslide event sizes are also an important proxy for the estimation of magnitude and intensity of past earthquakes, I thought our study might be interesting for the paleoseismicity community as well, and so I put together a brief summary.
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Between 1885 and 1938, the northern Tien Shan at the border between present Kyrgyzstan and Kazakhstan experienced a remarkable series of five major earthquakes, exceeding M6.9 and reaching up to M ~ 8 (1885 Belovodskoe M6.9, 1887 Verny M7.3, 1889 Chilik M~8, 1911 Chon Kemin M8, and 1938 Kemino Chu M6.9). Combined, the seismic moments add up to almost moment magnitude 9, which is a significant amount of strain released in roughly 50 years and across an E-W stretch of less than 500 kilometers. Even more intriguing is the fact that the ruptured region is located more than thousand km north of the nearest plate boundary and associated India-Eurasia collision zone. The macroseismic areas of these earthquakes include the present-day capital of Kyrgyzstan, Bishkek (Frunze) and the former capital and still largest city of Kazakhstan, Almaty (earlier names Alma Ata and Verny).
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Today’s paper round-up covers a very wide spectrum of earthquake related studies. We have work on tsunamis, turbidites, and lake paleoseismology, paleoseismological data from Asia, Archaeoseismology, mud volcanoes, the ESI-2007 scale, and an explanation on what the rise of the Andes is driven by. Enjoy reading!
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It’s only one month since my last paper update and yet I have nineteen interesting new studies for you. Today’s round-up includes tsunamis, tectonic geomorphology, environmental earthquake effects and soft sediment deformation, new techniques/technology, and some classic paleoseismology. Enjoy! more
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. more
Dear friends and colleagues,
The 7th International Workshop on Paleoseismology, Active Tectonics, and Archaeoseismology (PATA Days) will be held in the USA from 30 May – 03 June, 2016. The workshop is sponsored by the INQUA-TERPRO Commission and mainly organized by James McCalpin. The workshop includes several excursions and we welcome presentations on a broad list of topics related to seismic hazards and active tectonics: more
Marta Ferrater from the Universitat de Barcelona did a lot of research on the Alhama de Murcia Fault. Her most recent paper deals with how good we can measure lateral offsets along faults which move only very slowly. This is probably of great interest for many people working on slow faults, so I am glad that she agreed to write the following guest post: more
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. more
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. more