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Seismology

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This guest post was contributed by a scientist, student or a professional in the Earth, planetary or space sciences. The EGU blogs welcome guest contributions, so if you've got a great idea for a post or fancy trying your hand at science communication, please contact the blog editor or the EGU Communications Officer Laura Roberts Artal to pitch your idea.

Seismology for non-seismologists

Short Course at EGU2017, organized by the ECS-Team of the Seismology Division
Title
: SC76/SM10.11 – Seismology for non-seismologists
Time: Thursday 27 April, 13:30 – 15:00
Location: Room -2.91

This short course is dedicated to non-seismologists, with a particular focus for young scientists (graduates, PhD students and postdocs). The main goal of this short course is to provide an introduction into the basic concepts and methods in seismology and how these methods are applicable to investigate the near-surface and Earth’s interior. The course will highlight the role that advanced seismological analysis techniques can play in the co-interpretation of results from other fields in the geosciences, such as tectonics, physics, geology, geodynamics, volcanology and hydrology.

The topics covered this year will include
(1) what and how seismologists measure in land and at sea by Laura Parisi and Alba Gil.
(2) how seismologists study earthquake sources and how these studies relate to seismic hazard by Olaf Zielke.
(3) how seismologists image the interior of the Earth with and without earthquakes by Marco Galo and Nienke Blom.

We likely won’t turn you into a seismologist in 90 minutes, but would rather like to make you aware how seismological techniques can help you in geoscience. The intention is to discuss each topic in a non-technical manner, emphasizing their respective strengths and potential shortcomings. Not only will this course help non-seismologists to better understand seismic results but it will also facilitate more enriched discussion between different scientific disciplines.

The 90-minute short course will be run by fellow young seismologists and geoscientists, who will present examples from their own research and from reference papers for illustration. 15-20 minutes will be reserved for questions from the audience on the topics covered by the short course and general seismology.


By Koen Van Noten
Koen Van Noten is an earthquake geologist at the Geological Survey of Belgium. He investigates the influence of site effects on intraplate earthquake ground motions by Did You Feel It?” macroseismic data and near-surface geophysical techniques. Koen’s role as ECS is to encourage students to promote their results in seismology, geology and near-surface geophysics in various ways.

Some reminders for EGU2017 General Assembly

With only 3 days left for the kick off of the annual European Geosciences Union General Assembly (2017), here is a quick-list to go through in time for EGU.

First, read this page for information concerning activities for Early Career Scientists at the GA:
https://www.egu.eu/young-scientists/at-the-assembly/

Sunday 23th April: The Opening Reception, 18.30-21.00 in Foyer E.
Mingle and tingle with the crowd, old, not so old, and young scientists, all in one place. A perfect place for a cheer and networking. A gathering point for early career scientists provides the opportunity to meet like-minded fellows, especially if it is your first time at the General Assembly or you are coming alone.

EU2017 mobile app
The EGU2016 mobile app is now available for most smart phones. Go to http://app.egu2017.eu  to download the app. 

Short Courses
With an ever increasing number of short courses held at the GA,  probably there is one good course for you. Many are held during breaks, purposely not to coincide with other sessions. The full list is here:  http://meetingorganizer.copernicus.org/EGU2017/sessionprogramme/SC

A quick look on the Seismology Program:  http://meetingorganizer.copernicus.org/egu2017/meetingprogramme/sm

  • Tuesday – Thursday: Meet the EGU Division President and the ECS Representative of Seismology
    Get a unique opportunity to meet with P. Martin Mai, the current president for the Seismology Division and L. Parisi. You are invited to stop at the EGU booth to ask EGU related questions or discuss ways you would like EGU to improve. Martin and Laura will be available on Tuesday and Thursday during lunch, 12:00-13:30 / Room EGU Booth
  • Medal Lectures
    Get the opportunity to listen to world class experts in various geosciences. Medal Lectures are special sessions that give merit to distinguished scientists. They are usually followed by insightful (and thought provoking)  presentations. These lectures are well attended and seats are quickly taken.

Note for seismologists: the Beno Gutenberg Medal Lecture by Hitoshi Kawakatsu on Wednesday, 26th April between 11:00–12:00 / Room K1. 

  • WednesdayDivision Meeting for Seismology (after the Beno Gutenberg lecture)
    In the Division Meeting for Seismology (SM), the division president will present the latest information on the state of the division, statistics for abstracts and sessions in 2016, and the news related to the various divisional activities. All members are invited, and encouraged to actively participate in the meeting. Lunch is provided.  Wed, 26 Apr, 12:15–13:15 / Room K1
  • Wednesday: Recent activities of the Seismology Division Early Career Representative(s) 
    What is a POM? Ever read a Seismology Blogpost? Are you aware of our facebook and Twitter initiatives? Do you have any comments/recommendations and/or concerns with regards to EGU and/or the Seismology Division? This is the right opportunity to share ideas with your ECS representative(s). We highlight all Seismology activities on a poster that will be presented on Wednesday 26th April, 17:30-19:00 – at EGU2017-13751. Hall X3. Come over and let’s talk!
  • Wednesday 26th April, 20h: SEISMOLOGY SOCIAL EVENT : Meet us for a drink at Mel’s Craft Beers & Diner, Wipplinger-straße 9, 1010 Wien.

  • Thursday: Consider attending our yearly own Short Course: Seismology for non-seismologistsThursday 27h April, 13:30-15:00, Room -2.91. A dedicated short course directed to non-seismologists or early career seismologists, with a particular focus how to integrate seismology within your own research. Every year this short course has been a success. We likely won’t turn you into a seismologist in 90 minutes, but would rather like to make you aware how seismological techniques can help you in geoscience.

Early Career Scientists’ Lounge.

In the Red Level of the conference centre you can find a place to take a break, grab a free coffee or soft drink and gather your thoughts away from the buzz of the Assembly. The lounge is also a great place to catch up with colleagues you haven’t seen in a while and perhaps strike up a new collaboration. On the notice boards you can find information about cultural activities on offer in Vienna. There is also the opportunity to provide feedback via suggestion boards.


By Koen Van Noten

Koen Van Noten is an earthquake geologist at the Geological Survey of Belgium. He investigates the influence of site effects on intraplate earthquake ground motions by Did You Feel It?” macroseismic data and near-surface geophysical techniques. Koen’s role as ECS is to encourage students to promote their results in seismology, geology and near-surface geophysics in various ways.

EGU Seismology Division 2017 visibility survey

Dear Seismology Division blogpost, Facebook and Twitter followers,

The EGU Seismology Division has prepared an online survey to investigate how members are following our division’s activities online. The data we will acquire through this simple survey allows us to learn how we can improve our visibility and to which activities we could further focus. The results will NOT be used for any commercial activities. They will be shown during next month’s GA in Vienna. All division members are encouraged to take part and to spread the word !

Visit the survey here:
goo.gl/CrR7N2

The online survey is an initiative of the Seismology ECS Team on behalve of Koen Van Noten, Laura Parisi, Matthew Agius, Laura Ermert, Lucia Gualtieri, Kathrin Spieker and Martin Mai (EGU Seismology Division President)

Visit the Blog: http://blogs.egu.eu/divisions/sm/
Facebook page: https://www.facebook.com/EGUSeismologyDivision/
Division on Seismology webpage: www.egu.eu/sm/home/
Twitter account: https://twitter.com/EGU_Seismo


By Koen Van Noten

Koen Van Noten is an earthquake geologist at the Geological Survey of Belgium. He investigates the influence of site effects on intraplate earthquake ground motions by Did You Feel It?” macroseismic data and near-surface geophysical techniques. Koen’s role as ECS is to encourage students to promote their results in seismology, geology and near-surface geophysics in various ways.

Paper of the Month – Bubbles and seismic waves

Modified figure based on “Tiny Bubbles” by frankieleon 

Our paper of the month is  Bubbles attenuate elastic waves at seismic frequencies: First experimental evidence” (N. Tisato et al., 2015) commented by Luca De Siena.

Luca De Siena is Lecturer in Geophysics at the School of Geoscience, University of Aberdeen (UK). He received his PhD from the University of Bologna (Italy) with a scholarship from the INGV-Osservatorio Vesuviano for his work on seismic attenuation imaging of Mount Vesuvius and Campi Flegrei volcanoes. During his postdoc at the Institut für Geophysik, Westfälische Wilhelms Universität (Münster, Germany), Luca worked on the development of novel imaging techniques using stochastic wave propagation, whose application has led to novel attenuation and scattering models of Deception Island (Antarctica), Tenerife (Spain), and Mount St. Helens (US) volcanoes. His research interests include the development and application of attenuation and scattering tomography at lithospheric and mantle scales, and in sub-basalt/reservoir settings.

Luca will present us a paper by Tisato et al. that finally provides experimental evidence on the effects of fluids and gasses on seismic attenuation. The results nicely connect seismology with rock physics, and are important for any seismologist interested in using amplitude information to track fluids in settings, like volcanoes and reservoirs, where they represent a clear hazard/resource. The paper gives insight into processes that open a new seismology-rock physics research path, and better connects our Division with Geochemistry and Volcanology.


“Seismic attenuation is an outstanding tool to image the physical and thermal properties of the lithosphere, particularly in volcanic areas. But any seismologist studying and imaging attenuation in 3D is aware of a long-standing issue with researchers in different disciplines, such as petrology and volcanology: they want magma, and they will see it in our model. Since attenuation is so sensitive to hot structures and physical changes they will just pick an anomaly and model a sill.

Probably, also the seismologist wants that anomaly to be magma, in order to publish the highest-impact journals and be highly cited. For the average reader and the editor of these journals, there is in fact an ocean (of interest) between the “Seismic attenuation imaging of Yellowstone magma sill” and the “Seismic attenuation imaging of a high-attenuation domain under Yellowstone caldera that could be a magma sill/fluid reservoir/hot rock topping melting, please pick one”. The truth is we still have a long way to be able to characterize that domain in terms of magma/fluids/heterogeneity just by looking at seismic attenuation.

In their paper, Tisato et al. take a step towards this direction by concentrating on bubbles: in a laboratory, they prove that these microscopic objects are able to attenuate seismic waves at frequencies we use in the field. In addition, the best way to model this attenuation for imaging purposes is wave-induced-gas-exsolution-dissolution (WIGED), which I knew was an effective model to reproduce high seismic attenuation in magmas. Finally, a way to prove that magma fills all my low-Q areas? Not so much.

Bubbles are in fact crucial ingredients to model attenuation in fluids, and their relative percentage reduces and distorts seismic amplitudes in ways I have seen in seismic volcanic waveforms. I first read the paper with amazement at what our colleagues in rock-physics can actually pull out today. They can reproduce the physical processes I have been using throughout my career for imaging the Earth in their laboratories. The demonstration that the WIGED model is most effective to describe attenuation provides us with an ideal analytical input to image the Earth with attenuation, linking to petrological quantities related to the physical and chemical state of the Earth. The study thus provides us with an opening to multi-scale laboratory- field imaging techniques using attenuation.

The main strength of the work other researchers and industry will see is its application to fluid/gas monitoring. The use of seismic tomography based on WIGED is potentially a novel 4D technique better apt to monitor hazardous volcanic and reservoir structures. To me, the paper is the demonstration that seismology can aim to characterize the Earth and its complex processes at scales so far unexplored, once correct theoretical models and experimental evidences are provided, providing more reliable constraints to other disciplines.

The questions that came to my mind after reading it: Is the scale and level of heterogeneity in the laboratory the same I use in forward modeling? What if, with their results, I would be able to apply attenuation imaging to sample scale? And maybe use poroelasticity to link Q with porosity and permeability? A paper that lets you with so many ideas and is so good at connecting seismology with other disciplines is rare, and certainly worth reading.”


Reference: Tisato, N., Quintal, B., Chapman, S., Podladchikov, Y., & Burg, J. P. (2015). Bubbles attenuate elastic waves at seismic frequencies: First experimental evidence. Geophysical Research Letters, 42(10), 3880-3887.

Do you have questions, suggestions or comments? Please use the space below, or contact us on Facebook or Twitter @EGU_Seismo!

Are you an experienced seismologists and you want to be our next PoM author? Contact us at sm-ecs @ egu.eu

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