Start date: 2022-10-01   End date: 2026-09-30

Deadline for submitting applications: 2022-08-30

Requirements:

•  Master degree in geoinformatics, geophysics, physics or similar. It is allowed to submit applications by people who graduate from studies in the coming months and will submit the opinion of the master's thesis supervisor on its progress and the obligation to submit the master's diploma by 01/12/2022.
• Knowledge of research topics related to the propagation of seismic waves, seismic imaging, numerical and inversion methods
• Very good programming skills in one of languages (Fortran, C++, Python)
• Knowledge in the field of seismic data processing and interpretation
• Experience in HPC computing and clusters
• Very good English speaking and writing skills enabling the presentation of results at international conferences, communication, reading and writing scientific papers.

Tasks description: The PhD student will join the group implementing the NCN project no. 2021/43/B/ST10/00965 titled "Understanding of the influence of petit-spot volcanism on the structure of the lithosphere on the basis of multi-parameter, high-resolution seismic imaging of seismic data from the Japanese Trench”. The project is scheduled for 48 months. The main tasks include:

• Application of velocity model building methods – traveltime tomography and full-waveform inversion – to the wide angle ocean-bottom seismometer data
• Source code development and application of least-square reverse time migration scheme to the reflection streamer data
• Participation in doctoral school courses
• Reporting of the results during conferences and via scientific articles
• Participation in research visits

Title of the NCN call: OPUS 22

How to apply: To be employed, a candidate must participate in the Doctoral School of the Institute of Geophysics of the Polish Academy of Sciences. Applications for employment are submitted through recruitment to the Doctoral School, which takes place online in the IRK system (https://irk.us.edu.pl/), including the creation of an account in the IRK online recruitment system; payment of the enrolment fee (the date of the transfer is decisive); entering relevant information and documents.

Conditions of employment

Project scholarship: Approximately 3,690 PLN net per month for a period of 46 months

Employment: Specified period of 48 months, including the first 2 months of the IG PAS scholarship

Working time: full time

Additional information: The position is financed under the NCN project no. 2021/43/B/ST10/00965 titled "Understanding of the influence of petit-spot volcanism on the structure of the lithosphere on the basis of multi-parameter, high-resolution seismic imaging of seismic data from the Japanese Trench”. The project is scheduled for 48 months.

Project description: Petit-spot volcanism is recently discovered phenomenon that shed a new light on our understanding of the intraplate volcanism. Petit-spot volcanoes (or petit-spots) are small volcanoes that erupt along lithospheric fractures in response to plate flexure during subduction. Their discovery was of great significance, as it demonstrated, that tectonic processes have potential to cause intraplate volcanism Shortly after discovery of petit-spots, the debate emerged that the wide distribution of those volcanoes over relatively small area brings significant impact on the subduction system in terms of megathrust rupture nucleation and slip propagation. On the other hand, the petit-spots are just a small-scale surface evidences of the volcanic processes that take place in the deep lithosphere. Those processes are still not fully understood and have yet to be investigated. As for today, the high-resolution crustal-scale inversion and migration methods are the only robust techniques to image those variations.

The fundamental goal of this 4-years project is to couple leading-edge full-waveform based inversion and depth-migration techniques with different types of unique seismic data to retrieve the high-resolution models of subsurface in the outer-rise region of the Japan Trench – the area where the petit-spot volcanoes were discovered for the first time 15 years ago. In particular, we plan to reconstruct high-resolution P and S wave velocity models (Vp and Vs) using full-waveform inversion (FWI) of the ocean-bottom seismometer (OBS) data, as well as reflectivity image using least squares reverse-time migration (LSRTM) of the multi-channel streamer (MCS) data. On the methodological side of this proposal we firstly want to tackle the long standing problem of moving the velocity model reconstruction with FWI of OBS data beyond the acoustic approximation. In particular reconstruction Vs remains challenging both on the methodological and computing side, and therefore, establishing robust workflow for this type of FWI is now one of the technical challenges. Secondly, owing the fact that we will have access to the detailed FWI Vp model, we would like to adopt the LSRTM technique to fully exploit the potential of the academic MCS data for the purpose of reflectivity imaging. We want to obtain a detailed image of the changes in the sedimentary cover caused by petit-spot volcanism to understand how they alternate the inputs to the subduction zone and how it may affect the geodynamic system during nucleation and propagation of the megathrust earthquakes.

The thesis will be carried out under the supervision of:

dr hab. Mariusz Majdański (mmajd@igf.edu.pl) and dr inż. Andrzej Górszczyk (agorszczyk@igf.edu.pl) Institute of Geophysics of the Polish Academy of Sciences, ul. Księcia Janusza 64, 01-452 Warsaw.

The office for the PhD student will be located in KRAKÓW, ul. Gabrieli Zapolskiej 44.