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Multiple Announcements: ESC 2016 Session 19, Mendenhall Opportunity 16-12

Date: 04/11/2016

Dear SCEC Community, 

Please see below regarding the following:

1) USGS Mendenhall Opportunity 16-12: Investigation of the Variation of Structural Modal Properties with Vibration Amplitude Utilizing Recorded Data from Monitored Buildings
2) ESC 35th General Assembly Session 19: Advances in Borehole Networks, Data and Analyses


SCEC Information

1. USGS Mendenhall Opportunity 16-12: Investigation of the Variation of Structural Modal Properties with Vibration Amplitude Utilizing Recorded Data from Monitored Buildings

We would like to announce a post-doctoral opportunity (Mendenhall: 6-12)  to study variation of modal properties from the ambient to the strong motion regime of vibrations with a working title “Investigation of the Variation of Structural Modal Properties with Vibration Amplitude – Utilizing recorded data from monitored buildings.” Comparison of modal properties that are obtained through the analysis of vibration data collected from a structure during its operational (i.e., ambient) conditions with those results extracted from the structure's response recorded during seismic events (i.e., strong shaking) reveals two major trends: decreased modal frequency and increased damping during strong shaking – even though it has been found in several studies that critical damping ratios are in general smaller than used in design practice. While the amplitude‑dependencies described above are well known, the tendency in the current state of earthquake engineering practice is to accept the dynamic characteristics (frequencies, damping ratios, and mode shapes) observed during low-amplitudes of motion in lieu of those that structures exhibit during strong ground shaking.

Research proposals are invited to identify and characterize the aforementioned variation of dynamic structural characteristics by addressing the following issues:

• Development of predictive relationships for deducing modal properties of building structures during strong motion events from those identified through the analysis of ambient vibration data.
• Investigation of the soil-structure interaction effects on the amplitude dependency of the dynamic characteristics of structures.
The effort by the postdoctoral fellow may include the development and deployment of techniques and tools to efficiently process large quantities of data.

Please see the website for more information related to project description: http://geology.usgs.gov/postdoc/opps/2016/round16/16-12%20Celebi.htm

Other Mendenhall Post-doc Opportunities: http://geology.usgs.gov/postdoc/

The deadline to apply is May 2, 2016, with a proposed duty station of Menlo Park, CA.

Please contact Mehmet Çelebi  or Ertugrul Taciroglu with any questions: (celebi@usgs.gov or etacir@ucla.edu)

Applicants are encouraged to contact potential research advisors to discuss proposal ideas before developing a complete proposal.
Potential Advisors: Mehmet Çelebi (USGS, Menlo park, CA), Professor Ertugrul Taciroglu (UCLA).


2. ESC 35th General Assembly Session 19: Advances in Borehole Networks, Data and Analyses

Dear Colleagues and friends:

We’re organising a special session at the 35th General Assembly of the ESC in Trieste (4-10 September, 2016), where we plan to bring together the engineering, seismological, and geophysical communities to discuss borehole data, arrays, and approaches.

We cordially invite you to submit an abstract and drop by the session to discuss any aspect of borehole data analysis, including interferometry, material properties in the linear and non-linear range, site response, amplification, attenuation, and soil-structure interaction (http://www.35esc2016.eu/scientific-program/session19/).

Please note that the abstract deadline is 30 April 2016 !! See www.35esc2016.eu for the online submission form and more info on the meeting.

This year, the ESC pays special attention to poster presentations and student presenters, so young researchers are especially welcome.

Thank you, and hope to see you in Trieste!

Olga, Umit, Bojana, and Kyriazis

The analysis of data recorded by sensors installed in boreholes has yielded important information for numerous applications in the Engineering and Seismological communities. Borehole arrays can help estimate small-strain properties of the shallow layers and also improve our understanding of strong ground motion, including non-linear soil behavior and material properties, as well as liquefaction phenomena. Strong and weak motion data from depths of a few meters down to a few kilometers can give information on the mechanisms behind site amplification (such as basin-edge and other complex site effects related to the shallow geological structure) and site attenuation (such as anelastic attenuation, Q, and the high-frequency decay parameter, kappa; the latter may also bear on seismological problems such as stress-drop). Downhole arrays are also the best source of data for estimating input ground motion at bedrock level. When combined with arrays installed in nearby buildings, the joint data analysis allows a comprehensive study of wave propagation through the shallow layers and interaction with the building.

This session aims to bring together the Engineering, Seismological, and Geophysical communities and create a platform for discussion and exchange concerning borehole arrays, data, and applications. We welcome contributions from all aspects of borehole data analysis, including, but not limited to: interferometry, material properties in the linear and non-linear range, site response, amplification, and attenuation. We encourage novel and hybrid applications of vertical arrays, including coupled subsurface-and-superstructure arrays. We also seek to hear from those installing new arrays and compiling new datasets and public databases of downhole data, and to discuss exciting new possibilities for applications.

Session conveners:

S. Umit Dikmen (Bogazici University, KOERI, Dept of Earthquake Eng.), umit.dikmen@boun.edu.tr
Olga-Joan Ktenidou (GFZ German Research Centre for Geosciences), olga.ktenidou@gmail.com
Bojana Petrovic (GFZ German Research Centre for Geosciences), petrovic@gfz-potsdam.de
Kyriazis Pitilakis (Aristotle University Thessaloniki, Dept of Civil Eng.), kpitilak@civil.auth.gr

Invited speaker:

Stefano Parolai (GFZ German Research Centre for Geosciences)