Posts in the category »   «  ( 116 Posts )

  • Surface ruptures of the 1891 Nobi earthquake

    At the XIX INQUA congress in Japan I had the chance to see the surface ruptures of the 1891 Nobi earthquake during the mid-congress excursion M-2. This quake caused huge damage, but more interestingly for me, it produced amazing surface ruptures which are preserved even more than a hundred years after the event. The M7.5-M8 quake occurred in a mountainous area and was mainly strike-slip (more than 8 m!), but significant vertical uplift was found at step-overs. In 1991, the wonderful Neodani Fault Museum opened to the public, its main attraction being a paleoseismological trench exhibiting more than 5 m of vertical offset! Simply astonishing. Thanks to Atsumasa Okada, Heitaro Kaneda and Keitaro for this great excursion! more

  • Literature update

    Lots of paleoseismology and tsunami studies are currently being published… Here’s my update on the latest papers, including: Surface ruptures, seismic swarms, tsunamites, Asian tectonics, slip rates and archaeoseismology. Plus: A very interesting study on the 1911 Chon-Kemin M8.0 earthquake in the Kazakhstan/Kyrgyzstan border region, the source process reconstruced from analogue seismograms. Thanks to Ramon Arrowsmith for pointing me to this one. Enjoy!

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  • Paleoseismological field work in Kyrgyzstan

    A few weeks ago I spent ten days of field work in the Suusamyr Valley in Kyrgyzstan. In the framework of the EwF Project and COMET a team from Oxford (Eleanor Ainscoe, Austin Elliott, Richard Walker) and Kyrgyzstan (Kanatbek Abdrakhmatov, Azat Moldobaev) re-visited the epicentral area of the 1992 MS7.3 Suusamyr earthquake. This thrust earthquake is quite special for it produced intense and widespread secondary earthquake environmental effects (landslides, rockfalls, secondary ruptures, mud eruptions, etc.), but remarkably short primary surface ruptures only. Actually, surface ruptures of several metres height were found near the Suusamyr river, but limited to few hundreds of metres in length. Some 25 km to the west, another set of surface ruptures appeared, which were only about 1 m in height and less than 3 km long. Here are some impressions from our field work. more

  • What’s up? The Friday links (84)

    Isn’t it too hot to be inside and reading? For the night here are some short news on the top 100 paper of all time, the Landers earthquake and Landsat data. Today is Friday and here are your links!

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  • Paleoseismology Through Sedimentology

    The Megablock Complex: An example from the East African Rift

    Recognizing and interpreting seismite horizons (soft-sediment deformation generated by earthquakes) preserved in the sedimentary record is an underappreciated approach for paleoseismic analysis. The addition of sedimentological studies to a toolkit that includes other well-established methods, such as instrumental seismic monitoring and fault trenching, can provide a less expensive and more practical option for earthquake hazard prediction and preparation in certain areas. For example, this may be a good option in less developed regions and in areas where fault trenching may not be possible. Moreover, there is a lot that we can learn rheologically from the study of seismites that could be invaluable for modeling the behavior of the surface/near-surface during seismic activity. Similarly, investigating Quaternary strata in areas that may be prone to seismicity, which may or may not have a recorded history of major earthquakes, can illuminate important information about earthquake recurrence patterns and intervals, in much the same way as fault trenching. more

  • Symposium on Mega Earthquake Induced Geo-disasters – The field trips part II: Qipan gully debris flow

    It’s Friday – but instead of the Friday links I have the story of a giant post earthquake debris flow in the Wenchuan area for you. As I already announced in my last post about the field trip to the Wenchuan earthquake epicenter in frame of the International Symposium on Mega-Earthquake Induced Geo-disasters and Long Term Effects in Chengdu, China, I still wanted to blog about the Qipan gully debris flow that we also visited during the field trip. After giving you some background information I will take you on the hike with us. We will first see massive destruction in the residential area and then have a look at the debris flow deposits and some mitigation structures while climbing up the gully. Come on, let’s go! more

  • Symposium on Mega Earthquake Induced Geo-disasters – The field trips part I: Wenchuan epicenter

    In my last post I blogged about the International Symposium on Mega Earthquake Induced Geo-disasters and Long Term Effects in Chengdu, China, and now I want to report about one of the field trips that I participated after the symposium. While we spent the morning and early afternoon at the Qipan gully to look at a giant debris flow that occurred five years after the earthquake, in the afternoon we had the chance to visit the memorial site of the 2008 Mw 7.9 Wenchuan earthquake, which is basically the collapsed building of a middle school close to the epicenter that was left as it was after the earthquake. I want to report about this site first because it is more about the earthquake itself. In my next post I will report about the Qipan gully debris flow. more

  • What’s up? The Friday links (80)

    Here are some links I collected on today’s Kent Earthquake, the impossible task of earthquake prediction and some videos on Structure From Motion and Pacific tsunami propagation. Today is Friday and here are your links!

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  • Workshop ‘Earthquake activity and hazard in northwest Europe’, Belgium, 15 October, 2015

    Our colleagues in Belgium have reasons to celebrate! At the Membach station they’re monitoring seismic activity for 40 years now, and 20 years ago the superconducting gravimeter started working. To commemorate this the Royal Observatory of Belgium and the Public Services of Wallonia organize a scientific workshop on Earthquake activity and hazard in northwest Europe. The workshop will be held on 15 October 2015 at the Gileppe Dam Tower.

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  • Workshop ‘Tectonic and geodynamic evolution of Eastern Iran’, 2-6 November, 2015

    The workshop “Tectonic and geodynamic evolution of Eastern Iran” will be held in both Tehran (2 Nov) and Birjand (3-6 Nov). It will comprise 3 days of field excursion around Birjand showcasing the variety of Sistan’s geological highlights (from ophiolites, deformation events, sedimentary basins to ore-mineralizations), that will be open to ~60 people.  more

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