The Hokudan 2020 International Symposium on Active Faulting will take place from 13-17 January in Awaji City, Awaji Island, Japan. The symposium is held every five years. The 2020 event commemorates the 25th anniversary of the 1995 Kobe earthquake. All important information on this meeting is available here: https://home.hiroshima-u.ac.jp/kojiok/hokudan2020.html
This event is supported by INQUA – the International Union for Quaternary Research and its TERPRO commission. For more information, please contact Koji Okumura (kojiok@hiroshima-u.ac.jp) or Shinji Toda (toda@irides.tohoku.ac.jp).
On July 4th and 5th, 2019 two earthquakes (Mw 6.4 and Mw 7.1, respectively) occurred in eastern California and produced distinct surface ruptures. Field surveys started immediately after the first event and, less than two weeks later, a provisional map of surface rupture was compiled and made available to everyone (Contributors from USGS, CGS, UNR, USC, CSUF). I downloaded the map and kmz files of the ruptures from the SCEC response site, which contains tons of fruitful information.
The two strike-slip earthquakes ruptured two perpendicular faults, the first running NE-SW with left-lateral slip and the second running NW-SE with right-lateral slip (Figure 1). The location of the earthquake falls within the Eastern California shear zone, a region of distributed faulting associated with motion across the Pacific-North America plate boundary, and an area of high seismic hazard.
Figure 1. Left: ground breaks caused by the 2 earthquakes. Right: simplified trace, used as main fault.
Ruptures come
with a variable degree of complexity: some sectors show a “simple” single
strand, others show multiple sub-parallel or diverging splays. Distributed
faulting represents displacements occurred off the principal fault and is
generally made up by less continuous ruptures, which can be located tens of
meters to a few kilometers from the principal fault trace. A method to evaluate
the fault displacement hazard has been proposed by Youngs et al. (2003) and
later refined by Petersen et al. (2011); the former study analyzed normal
faults, while the latter analyzed strike-slip faults.
Basically,
the method defines the conditional probability of faulting occurrence as a
function of distance from the principal fault and derives scaling relations
between rupture probability and distance. I applied the same method on the 2019
sequence and compared the output with the results by Petersen; results are
grid-dependent – since available data are still provisional, I used a quite
coarse grid size of 200 m, more detailed studies will come.
Results are in good agreement (Figure 2): the 2019 ruptures show a higher than average rupture probability at 0-2 km from the main fault, but also taper out faster than the previous events.
Figure 2. Comparison between the 2019 events (blue: July 4th; red: July 5th) and data by Petersen et al. (empty circles). The probability of occurrence of faulting is plotted as a function of distance from the main fault (left: linear horizontal axis; right: logarithmic scale).
References:
Petersen, M.
D., et al. (2011). Fault displacement hazard for strike-slip faults. BSSA,
101(2), 805-825.
Youngs, R.
R., et al. (2003). A methodology for probabilistic fault displacement hazard
analysis (PFDHA). Earthquake Spectra, 19(1), 191-219.
The next INQUA meeting on Paleoseismology, Archaeoseismology, and Active Tectonics (PATA Days) will be held in Hornitos, Chile, from 8-12 November, 2020. Download the 1st circular here (PDF, 400 kb).
Dr. Gülsen Ucarkus send us the first circular for the following interesting meeting:
We would like to invite you to the international meeting organized by Active Tectonics Research Group (ATAG) of Turkey in commemoration of 20th Anniversary of 1999 Marmara Earthquakes. Following these two devastating earthquakes (1999 Mw 7.4 İzmit and 1999 Mw 7.2 Düzce Earthquakes), a vast number of international/national projects carried out in the Marmara Sea region of Turkey and the outcomes of research done contributed significantly to multi-disciplinary studies in active tectonics. The meeting aims to revisit the results of these important number of observations together with new research going on to highlight the current state of seismic hazard in Marmara Sea where the next big earthquakes is expected to occur.
These are great opportunities for PhD students and postdocs. A huge research programme in South Korea is now devoted to investigate the active faults of the country and to understand the seismic hazard, after two damaging earthquakes hit the country recently.
Recruiting PhD Research Student and Postdoctoral Researcher
Starting from March 2019, ‘The Korean Active Fault Research Group (KAFRG)’ and ‘The Institute of Active Fault and Earthquake Hazard Mitigation (IAFEHM)’ at Pukyong National University in South Korea are looking for competent and enthusiastic research students and geologists for PhD and Post-doc.
Our research group and institute are currently leading active fault investigations and researches in South Korea. We also have been implementing collaborative researches with various domestic and overseas universities and research institutes. The ongoing main projects of our research group are ‘Investigation of active faults on the Korean Peninsula’ and ‘The safety evaluation for geological conditions and earthquake hazard for nuclear power plant sites and waste disposal facilities.’
The initial employment – contract period is 1 year, and depending on the researcher’s achievement and contribution to the group the working year(s) can be extended. The annual salary will be arranged according to the researcher’s research experiences and the performances. more
The #PATA18 workshop will be held from 25-27 June and the Summer School will take place on 28 June. Under- and post- graduate students can now attend both these events, with special rates:
Workshop (25-27 June): 30 Euros (attendance only)
Summer School (28 June): 30 Euros (attendance plus two meals)
Workshop + Summer School combo: 50 Euros.
There is also the possibility to stay at the Aristotle University camping ground at a very low price, by bringing your own tent or renting one on site. To register for these events and for more information, please contact Ass. Prof. Alexandros Chatzipetros at ac@geo.auth.gr no later than Jun 15th, 2018. more
I hope you’ve had a great start into the new year. A lot of new and exciting papers have been published at the end of the old one, including work on New Zealand and Europe. Enjoy reading and have fantastic new year 2018!
Last October I was given the chance to attend the “iRALL school on field data collection, monitoring, and modeling of large landslides” in Chengdu, China. During the school, we spent one week in the epicentral area of the Ms=8.0 2008 Wenchuan earthquake, where I was able to take some interesting pictures of earthquake damage and coseismic landslides. Then other things happened, like the earthquakes in Italy and New Zealand, with exciting sights from the field shared here, and I never ended up sharing my Wenchuan pics, which I want to do now. more
