Seismic imaging and monitoring of environmentally induced changes in the structure of critical large scale artificial and natural objects

Start date: 2023-10-01 End date: 2026-09-30

Deadline for submitting applications: 2023-06-15

We are looking for a highly motivated PhD student to join our near-surface team at the Institute of Geophysics, Polish Academy of Sciences. The PhD student will work on a project related to monitoring of temporal changes in the structure of critical objects like earth dams and landslides. The student will be part of dynamic international team and contribute to development of environmental seismology field with strong application contribution.

 Requirements:

• Master degree in geophysics, physics, engineering geology 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.

• Knowledge of research topics related to near-surface seismic, seismic imaging and passive seismic methods

• Near-surface field work experience

• Basic programming skills in one of languages (C++, Python, Matlab)

• Knowledge in the field of seismic data processing and interpretation

• Very good English speaking and writing skills enabling the presentation of results at international conferences, communication, reading and writing scientific papers.

• (optionally) experience with Distributed Acoustic Sensing (DAS) will be an advantage

 

Tasks description: The PhD student will join the group implementing the NCN project no. 2022/45/B/ST10/00658 titled "Seismic imaging and monitoring of environmentally induced changes in the structure of critical large scale artificial and natural objects”. The project is scheduled for 48 months. The main tasks include:

• Participation in organization and execution of field experiments in various terrain conditions in Poland with standard near-surface seismic methods and advances techniques (DAS)

• Seismic data processing including MASW, seismic tomography and reflection seismic imaging

• Participation in passive seismic data processing and analysis

• Participation in doctoral school courses and research visits

• Reporting of the results during conferences and via scientific articles

• Participation in activities of the department (Geophysical Imaging)

Title of the NCN call: OPUS 23

How to apply: To be employed, a candidate must participate in the Geoplanet Doctoral School of the Institute of Geophysics of the Polish Academy of Sciences. Required documents should be sent in electronic form in one PDF file (by e-mail) only to the address: studia.doktoranckie@igf.edu.pl

The following documents are required in the recruitment procedure:

1. The motion to enroll in the Doctoral School along with the consent for processing personal data for the recruitment purposes and the declaration about familiarizing with the present Regulations. The specimen of the motion is included in the Attachment 1 to the present Regulations.

2. A copy of the diploma certifying the completion of studies or a certificate confirming the completion of studies. In the case when the candidate is not in the possession of the above mentioned documents, he/she is obliged to deliver them before the start of the education in the Doctoral School. The documents are not required from the person referred to in Article 186 paragraph 2 of the Law.

3. The list of grades obtained during the first-cycle (B.A., B.Sc.) and second-cycle studies (M.A., M.Sc.) or the list of grades obtained during the long-cycle Master Degree studies.

4. The curriculum vitae containing the course of the existing education and employment, the list of publications, information on the involvement in scientific activity (membership in student research groups, participation in scientific conferences, internships and trainings, obtained awards and distinctions).

5. A letter of motivation containing a short description of interests and scientific achievements and the justification why the candidate intends to undertake the education in the Doctoral School.

6. Certificates or other documents stating the level of command of English language if the candidate is in possession of such documents.

7. At least one letter of recommendation from the current research supervisor, academic teacher or research worker describing the candidate and his/her scientific activity that has been carried out by him/her so far. The letter can be sent by the candidate or directly by the person who wrote the letter. It is also possible that the candidate indicates a person who is a research worker or an academic teacher and holds the scientific degree from whom the recruitment commission may independently obtain such an opinion. In such a case the recruitment commission asks for such an opinion within the term that allows for taking it into consideration during the recruitment time. The possible ways to deliver the letter are included in the recruitment announcement.

Financial terms

Project scholarship: Approximately 3,690 PLN net per month for a period of 48 months

Additional information: The position is financed under the NCN project no. 2022/45/B/ST10/00658 titled "Seismic imaging and monitoring of environmentally induced changes in the structure of critical large scale artificial and natural objects”. The project is scheduled for 48 months.

Project description: Climate changes are one of the main challenges of modern geosciences. Globally, its current state is well monitored in terms of sea ice and glaciers thawing or annual temperature increases. Current, state of the art technology allows precise, real-time continuous monitoring of our globe. Such precise data allows us to estimate the future evolution of the environment. However, there is still a significant lack of knowledge in terms of changes occurring under the surface. One of the key problems related to climate changes is estimation, how those factors and changing hydrological regimes in Poland impact critical infrastructure, and are potentially hazardous to society. Examples here are artificial objects like large dams and flood embankments, but also natural objects like landslides. Landslides, being sensitive to water changes can be easily triggered due to changes in monthly precipitation schemes, or changes in retention periods. Similarly, flood embankments are endangered due to more extensive precipitation, and thus a larger amount of water they have to stop. The scientific aim of the project is to image and monitor the temporal changes in the internal structure of large scale critical earth objects with adapted state of the art seismological technologies and methods. In the project we would like to use the most advanced seismic methods to image temporal changes in three different scale objects related to water circulation in the environment: large scale earth filled dam, massive creeping natural landslide, large flood embankment. Moreover, we would like to propose a new methodology that combines different geophysical methods and gives the most precise image of the internal structure in each case. Surveying environmental changes using active geophysical methods is not new on a global scale. However, the idea of using the latest seismic techniques in time lapse manners is leading to the study of climate-related changes in Poland and their impact on critical zones. Currently, multiple research teams are studying climate-related changes across polar regions, where they are easy to observe. Also, the effort to monitor natural hazards in Europe is widespread. With recent developments in the high-density acquisition and advanced data interpretation techniques, it is possible to investigate those changes in places where the amplitude of climate-related factors is smaller or slower. Because of the unprecedence accuracy of imaging, thanks to the high-resolution seismic techniques, the smallest perturbation in the subsurface can be observed with great precision even at large depths. The overall data quality significantly exceeds every previously used technique and provides new insight into the subsurface of critical infrastructure and natural hazard zones. Moreover, those non-invasive techniques can be used in critical and protected objects and not cause further devastation. Additionally, our survey will be the first in Poland to use the fiber optic cables system, which is the latest development in terms of subsurface structure imaging. Similar systems will be used for studying environmental problems in the following years, and thus estimation of their limitations and possibilities in such studies is essential. Besides of research papers and conference presentations we plan a series of popular science proceedings in the form of a website, lectures and short notes for the local population presenting main scientific findings of the project and their input for understanding the environmental seismology and dynamics of subsurface climate evolution, which will be published in open video repository. These materials, dedicated to a wide, non-scientific public will explain geohazard problems related to hydrological variations in the near-surface caused by changing climate in Poland.

The thesis will be carried out under the supervision of:

Prof. dr hab. Mariusz Majdański (mmajd@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 Warsaw, ul. Księcia Janusza 64

Robust Optimization of Inverse Problems for Wave-based Seismic Imaging

Start date: 2023-09-01 End date: 2027-08-30

Deadline for submitting applications: June 15, 2023

 

We are looking for two highly motivated PhD students to join our computational imaging research teams at the Institute of Geophysics, Polish Academy of Sciences. The two PhD students will work on a project to develop robust optimization methods for full waveform inversion (FWI), with an emphasis on theory development and application on synthetic and real data. The project's goals will be met through an interdisciplinary approach that includes computational geophysics, computational mathematics, nonlinear optimization, and HPC computing. Existing FWI methods, such as standard reduced-space FWI and extended FWI techniques based on model and source extension, will be examined.

 

The first project focuses on developing appropriate robust and efficient FWI methods. The student will collect existing methods developed under various names in various fields for FWI convexification. The methods based on source extension and model extension have recently demonstrated good potential for solving difficult FWI problems that could not be solved using traditional FWI methods. The student will examine the advantages and disadvantages of these two groups of methods, looking for methodological similarities and differences. The student will concentrate on establishing the theoretical link between his two groups of methods and comparing their performance on benchmark models. In this thesis, we will concentrate on developing a general method that possesses the robustness property of these methods.

 

The second project focuses on adapting the recently proposed multiplier waveform inversion (MWI) to elastic FWI and real-world applications. MWI uses the multiplier method, also known as the augmented Lagrangian method, to solve the FWI formulation. The focus here is on efficient construction of Lagrange multipliers rather than dealing with augmented wave equations and large Hessian matrices. Preliminary tests have yielded very interesting results in terms of increasing the convergence of FWI without dealing with complicated Hessian matrices, simply by gradient ascent update of the multiplier and gradient descent update of the model parameters. To better understand the algorithm's behaviour, the student will concentrate on the physical interpretation of the multipliers. One of the main advantages of MWI over other extended FWI methods-based source extensions is that it is very efficient and suitable for time-domain applications because it does not require the use of Hessian matrices. This property enables us to scale it up to large-scale applications.

 

The students will be part of a solution-oriented dynamic international team and contribute to advancing the state-of-the-art in both theory and application of wave-based imaging and FWI. 

Requirements:

• Master degree in geophysics, applied mathematics, 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.
• Knowledge of research topics related to the propagation of seismic waves, seismic imaging and inversion methods, and seismic data processing.
• Knowledge in the field of optimization methods and numerical analysis.
• Very good programming skills in Matlab and one of languages Python, Fortran, C++.
• Experience in HPC computing and clusters is very welcome.
• Very good English speaking and writing skills enabling the presentation of results at international conferences, communication, reading and writing research papers in peer-reviewed journals.
• Good interpersonal skills and the willingness to work in a multicultural team are expected.

 

Title of the NCN call: SONATA BIS-12

How to apply: To be employed, a candidate must participate in the Geoplanet Doctoral School of the Institute of Geophysics of the Polish Academy of Sciences. Required documents (phdstudies.php) should be sent in electronic form in one PDF file (by e-mail) only to the address: studia.doktoranckie@igf.edu.pl.

 

Conditions of employment

Project scholarship: Approximately 3,690 PLN net per month for a period of 48 months

Employment: Specified period of 48 months

Working time: full time

Additional information:

The PhD student will join the group implementing the NCN project no. 2022/46/E/ST10/00266 titled "Robust Optimization of Inverse Problems for Wave-based Seismic Imaging”. The project is scheduled for 48 months. Beside doing research on the selected thesis topic, student must also participate in doctoral school courses, participate in research visits, report the research results in the related scientific conferences and write research articles

The thesis will be carried out under the supervision of: Professor Ali Gholami (agholami@igf.edu.pl) Institute of Geophysics of the Polish Academy of Sciences, ul. Księcia Janusza 64, 01-452 Warsaw.

The following documents are required in the recruitment procedure:

1. The motion to enrol in the Doctoral School along with the consent for processing personal data for the recruitment purposes and the declaration about familiarizing with the present Regulations. The specimen of the motion is included in the Attachment 1 to the present Regulations.
2. A copy of the diploma certifying the completion of studies or a certificate confirming the completion of studies. In the case when the candidate is not in the possession of the above mentioned documents, he/she is obliged to deliver them before the start of the education in the Doctoral School. The documents are not required from the person referred to in Article 186 paragraph 2 of the Law.
3. The list of grades obtained during the first-cycle (B.A., B.Sc.) and second-cycle studies (M.A., M.Sc.) or the list of grades obtained during the long-cycle Master Degree studies.
4. The curriculum vitae containing the course of the existing education and employment, the list of publications, information on the involvement in scientific activity (membership in student research groups, participation in scientific conferences, internships and trainings, obtained awards and distinctions).
5. A letter of motivation containing a short description of interests and scientific achievements and the justification why the candidate intends to undertake the education in the Doctoral School.
6. Certificates or other documents stating the level of command of English language if the candidate is in possession of such documents.
7. At least one letter of recommendation from the current research supervisor, academic teacher or research worker describing the candidate and his/her scientific activity that has been carried out by him/her so far. The letter can be sent by the candidate or directly by the person who wrote the letter. It is also possible that the candidate indicates a person who is a research worker or an academic teacher and holds the scientific degree from whom the recruitment commission may independently obtain such an opinion. In such a case the recruitment commission asks for such an opinion within the term that allows for taking it into consideration during the recruitment time. The possible ways to deliver the letter are included in the recruitment announcement.