Text: Gösta Hoffmann with contributions by Michaela Falkenroth, Valeska Decker, Bastian Schneider and Christoph Grützner
“The beaches in Oman are pristine.” What sounds like an introductory sentence to a tourist brochure has scientific significance. Natural conditions without anthropogenic overprint are characteristic for vast stretches along the 1700 km coastline of Oman from the Strait of Hormuz in the north to the border of Yemen in the south. This situation allows geological research addressing Quaternary sea-level change on various timescales spanning from minutes to millennia. Over the last couple of years, we carried out research funded by the Omani Government and the German Research Foundation (DFG). Our findings are currently published in a series of papers (Schneider et al. 2018; Ermertz et al. 2019; Falkenroth et al. 2019, subm.; Hoffmann et al. 2020a, b) and are briefly summarised here.
There is a wonderful, amazing, extraordinary postdoc position open at Oxford University: Palaeoseismology of Central Asian Earthquake Ruptures.
We seek to appoint a postdoctoral research assistant to undertake investigations of large earthquakes within the interior of Asia. The post is part of a project funded by the Leverhulme Trust called EROICA. The successful candidate will work closely with Professor Richard Walker, and will join a vibrant community of active tectonics researchers in Oxford within the Earthquake Geology and Geodesy group.
The researcher will be responsible for the detailed mapping of palaeo-earthquake ruptures, the construction of slip distributions from individual earthquakes, the analysis of high-resolution satellite imagery, the construction of digital topographic models, and the selection of sites for long-term slip-rate determination using field investigation. The PDRA will also be involved in planning and carrying out fieldwork to verify remote-sensing observations, to collect samples for dating, and to excavate and interpret palaeo-seismic trenches. We expect the researcher to help in supervising doctoral and masters student research projects, in addition to undertaking their own research.
On 21 August an MD4.0 earthquake hit the Island of Ischia, Italy. The event occurred at a depth of only ~2 km. Despite the low magnitude, the earthquake had dramatic consequences, and two people were killed by collapsing houses. The INGV EMERGEO working group and CNR-IAMC have now published a report on the coseismic effects of this earthquake, which include ground cracks and mass movements. The full report can be found at earthquakegeology.com or downloaded as a pdf here (3.15 MB).
Please cite the report as: EMERGEO Working Group, Nappi et al. (2017). The august 21, 2017 Isola di Ischia (Casamicciola) earthquake: Coseismic effects, doi:10.5281/zenodo.1003188
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. more
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! more
A lot of new papers have been published on paleoseismology, earthquake geology, active tectonics and tsunamis last month. We have research on slowly deforming regions, on the active tectonics of Mexico, New Zealand, Armenia, and Iran, new data from the Kumamoto earthquake, plus some marine/coastal paleoseismology and tsunami studies. Enjoy reading!
The Chilik-Chon Kemin Fault Zone is a major left-lateral strike-slip fault zone in Kazakhstan and Kyrgyzstan, just a few tens of kilometres east of Almaty and north of Lake Issyk Kul. It has seen one of the largest continental earthquakes ever recorded in 1889, with an estimated magnitude of ~M8.3. In July and August I had the chance to visit this fault zone for two weeks together with Angela Landgraf from Potsdam and Aidyn Mukambaev from the National Data Centre, thanks to a travel grant from COMET (thanks so much, COMET!) and with support from the EwF Project. We wanted to find out more details about the tectonic geomorphology of this fault zone and we wanted to study the slip rate and earthquake recurrence intervals. So we took our drone, shovels and picks and set off for a field trip into the mountainous wilderness. Since I will leave for another field trip to Kazakhstan (Dzhungarian Fault) tomorrow, I will leave you with some impressions from our field work and provide more information once the paper is published…
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).
[Update 15 February 2017: Since Sascha is an author here now, the post was attributed to him.]
Greece is one of the main targets of RWTH Aachen’s Neotectonics & Geohazards group. They worked on paleo-tsunamis, active faults on the Peloponnese, in Attica, and on Crete, and on the application of terrestrial LiDAR and shallow geophysics for active tectonics research. In their latest paper, Sascha Schneiderwind et al. developed a methodology to aid paleoseismic trenching studies. They use t-LiDAR and georadar to better and more objectively characterise lithological units. His paper includes nice examples from Crete and from the famous Kaparelli Fault. Here is his guest blog: more
A few weeks ago, Nadine Reitman (USGS) published an interesting paper about the use of Photogrammetry for Paleoseismic Trenching in BSSA. In this guest blog she shares her key findings and explains how to minimise errors without spending too much time measuring control points. Thanks Nadine!
Structure-from-motion (SfM) is now routinely used to construct orthophotos and high-resolution, 3D topographic models of geologic field sites. Here, we turn SfM on its side and use it to construct photomosaics and 3D models of paleoseismic trench exposures. Our results include a workflow for the semi-automated creation of seamless, high resolution photomosaics designed for rapid implementation in a field setting and a new error analysis of SfM models. more