Tena Belinić Topić on research stay in Bergen 

Sep 19, 2023 | News

Tena Belinić Topić, a collaborator on the CRONOS project, spent three months on a research stay at the University of Bergen, specifically within the Department of Earth Science. Her stay extended from April to June 2023, during which she collaborated with distinguished scientist Stéphane Rondenay and his research team. The primary purpose of her work was to start the analysis of seismic data collected by CRONOS stations in Dalmatia and neighboring stations in Croatia and Bosnia and Herzegovina to provide a more precise definition of the lithospheric structure in the region. 

Stéphane Rodenay and Tena Belinić Topić at the Department of Earth Science,  April 7, 2023. 

During the first month of her stay in Bergen, Belinić Topić dedicated her time to familiarizing herself with the [PyGlimer] (https://pyglimer.github.io/PyGLImER/index.html) program, specialized in computing P and S receiver functions. During this period, she collected a substantial amount of data for further analysis, including data from 123 stations across 11 different seismological networks. These data were acquired from the ORFEUS website or directly from individual seismological networks. The analysis included more than 300 teleseismic events recorded from the beginning of 2016 to April 2023. 

On May 11, Belinić Topić held a seminar titled “Exploring the lithospheric structure beneath the Dinarides using seismograms of teleseismic earthquakes.” The seminar was attended by roughly 20 colleagues from the University of Bergen, with whom she engaged in an interesting discussion regarding the origin and structure of the lithosphere beneath the Dinarides. 

Map of the seismic stations used in receiver function analysis.
Tena Belinić Topić in her office at the Department of Earth Science. 

During the second month of her stay, collaborator Belinić Topić completed the computation of P and S receiver functions for a wider Dinaridec area, using the PyGlimer program. She also repeated the entire process of calculating receiver functions using two additional programs, rf (https://rf.readthedocs.io/en/latest/index.html) and Seispy (https://seispy.xumijian.me/index.html), to compare the results obtained by different software on the same dataset. A plan is to perform the entire analysis again at the end of 2023, aiming to gather additional data from stations set up as part of the CRONOS project in Dalmatia to enhance result accuracy. 

On June 8, Tena Belinić Topić, along with Iva Dasović, participated in a meeting with colleagues Lars Ottemøller, Stéphane Rondenay, Felix Halpaap, and Hasbij Ash Shiddiqi from the University of Bergen. During this meeting, their colleagues presented the outcomes of their ongoing research and demonstrated methods for creating high-quality earthquake catalogs, using North Sea data as an example. Additionally, on June 13, Belinić Topić attended lectures at the 54th Nordic Seismological Seminar, held near Bergen on the island of Herdla. Approximately 30 scientists from Nordic research groups participated in the conference, focusing on topics related to seismicity, seismic hazards, seismic network infrastructure, and data management. 

Presentation by Hasbij Ash Shiddiqi at the 54th Nordic Seismological Seminar, June 13, 2023
Tena Belinić Topić and Iva Dasović at the 54th Nordic Seismological Seminar, June 13, 2023. 

During the final month of her stay, collaborator Belinić Topić calculated P and S receiver functions along a profile across the Adriatic Sea and worked on further developing the PyGlimer program. She started the creation of tools for 3D visualization of results in the Python programming language, as well as functions for easier selection of stations and networks used in the analysis. The results of the profile were tested using the  [PyRaysum](https://paudetseis.github.io/PyRaysum/)  program, which generates sets of theoretical receiver functions for various input models.  

Example of receiver functions for the profile across the Adriatic Sea, presented during a meeting on June 22, 2023. 

Throughout her research stay, Belinić Topić actively engaged in discussions at Wednesday seminars under the title “Geolunch,” where numerous colleagues, including geodynamic experts and seismologists, presented the results of their research. Additionally, every Thursday, she held working meetings with Stéphane Rondenay to collaboratively go through various steps of the analysis and plan the continuation of their research. 

Tena Belinić Topić and Stéphane Rodenay at the Department of Earth Science, meeting on June 15, 2023. 

The key outcomes of this research stay are computed receiver functions for the wider Dinaric region, which will contribute to a better understanding of the crustal and lithospheric structure in the area. By conducting the analysis again at the end of 2023, further improvements in accuracy and clearer identification of structural discontinuities are expected, even though significant results are already visible.