Dr. Divya Sekhar Vaka

Satellite Remote Sensing Analyst, GEOFEM

Dr. Divya Sekhar Vaka is a Satellite Remote Sensing Analyst at GEOFEM, with eight years of experience in InSAR for infrastructure and environmental monitoring. He holds a PhD in SAR Interferometry from the Indian Institute of Technology Bombay and an MTech in Remote Sensing from Andhra University, India. His expertise lies in using InSAR for monitoring and analyzing urban subsidence, slope stability (including landslides, mines, tailing dams), subsidence due to oil/natural gas extraction, groundwater exploitation, and earthquake deformations, with a specific focus on land and geohazards. He is a member of IEEE, IEEE-GRSS, ISPRS, and ISRS. He has participated, published, and reviewed technical papers in reputed conferences and journals.

Dr. Sekhar has been a team member on several projects funded by the European Space Agency and other European funding bodies, and he has successfully completed numerous commercial projects. His interests and skills encompass a wide range of areas, including machine learning, deep learning, geophysical modeling, GPS-GNSS, SAR-optical data fusion, change detection, sea level rise, and geospatial analysis.

Research Interests

Technical Skills

• Programming Skills: MATLAB, Python

• Software and Tools: Jupyter Notebooks, GMTSAR, StaMPS, ISCE, ArcMap, ERDAS Imagine, ENVI, SNAP

• Cloud Platforms: Google Earth Engine, ESA RSS CloudToolbox, ASF OpenSARlab

Education

• Ph.D. - Geoinformatics and Natural Resources Engineering
  Indian Institute of Technology Bombay, Mumbai
  2016 — 2022
  Thesis: Studies on Land Surface Deformation Mapping using Interferometric Synthetic Aperture Radar Time Series Techniques
  Supervisor: Prof. Y. S. Rao ⋆ CPI: 8.1/10.0
• M.Tech. - Remote Sensing
  Andhra University, Visakhapatnam
  2012-2015
  Project: Generation of Land-use Plans for Sustainable Resource Development using Remote Sensing and GIS
  Supervisor: Prof. G. Jai Sankar ⋆ CGPA: 8.9/10.0 (First Class with Distinction)
• B.Tech. - Electronics and Communication Engineering (ECE)
  Jawaharlal Nehru Technological University, Kakinada
  2008 — 2012
  Project: Remote Monitoring of Weather Parameters using Vaisala Weather Transmitter WXT510
  Supervisor: Prof. G. Suresh ⋆ Percentage: 75.48% (First Class with Distinction)

Experience

• Satellite Remote Sensing Analyst
  GEOFEM, Nicosia, Cyprus
  March 2024 — Present
  ★ Responsible for Optical and SAR image analysis, data processing, result intrepretation and report writing
  ★ Working on various commercial and sponsored projects involving slope stability analysis, satellite derived bathymetry, infrastructure monitoring etc.
  ★ Responsible for project proposal writing and documentation
• Teaching Assistant
  Indian Institute of Technology Bombay, Mumbai
  July 2016 — July 2021
  ★ PG level courses:
  GNR 647-Microwave Remote Sensing;
  GNR 653-Data Analysis Methods for Geospatial Applications;
  GNR 621-Natural Resources: Hydrosphere, Cryosphere, and Atmosphere;
  GNR 617- Image Interpretation Lab.
  ★ Ph.D. level course:
  GNR 805-Advanced Concepts in Polarimetric SAR Image Analysis.
• Software Analyst
  Hexagon Capability Center India Pvt. Ltd., Hyderabad
  November 2014 — January 2016
  ★ Responsible for Quality Assurance and Quality Control of GeoMedia Suite of Products.
  ★ Pat on the Back award in Hexagon Geospatial Division for rigorous testing and timely integration of raster engine into the product.
• Project Research Associate
  CGARD, National Institute of Rural Development & Panchayati Raj, Hyderabad
  February 2014 — September 2014
• Project Trainee
  Electronic Corporation of India Limited (ECIL), Hyderabad
  February 2012
• Project Trainee
  Visakhapatnam Steel Plant (RINL), Visakhapatnam
  May 2011

Awards and Synergistic Activities

Awards

• Best Paper Award in IEEE India Geoscience and Remote Sensing Symposium (InGARSS 2020) conference

• MHRD Fellowship and Institute Teaching Assistantship during M.Tech. and Ph.D., respectively.

• Central Sector Scholarship for College and University Students by MHRD during B.Tech.

• Pat on the Back award for best performers in Hexagon Geospatial Division for rigorous testing and timely integration of raster engine into the product.

Travel Grants

• Institute (IIT Bombay) Travel Grant for attending International Conference IEEE IGARSS 2018 in Valencia, Spain

• IEEE GRSS Travel Grant for attending InGARSS 2023 in Bangalore, India

Synergistic Activities

• Journal Reviewer:
  Acta Geodetica et Geophysica (Springer), Environmental Science and Pollution Research (Springer), Geocarto International (Taylor & Francis), Remote Sensing Letters (Taylor & Francis), The Imaging Science Journal (Taylor & Francis)

• Professional Memberships:
  Indian Society of Remote Sensing (Life Member), IEEE (Member), IEEE Geoscience and Remote Sensing Society (Member), IEEE Young Professionals (Member)

Publications

Journals

1. Vaka, D.S.; Yaragunda, V.R.; Perdikou, S.; Papanicolaou, A., InSAR Integrated Machine Learning Approach for Landslide Susceptibility Mapping in California. Remote Sensing 2024, 16, 3574.
2. Vaka, D. S., Rao, Y. S., and Bhattacharya, A., Time series analysis of the preseismic and postseismic surface deformation of the 2017 Iran-Iraq earthquake derived from Sentinel-1 InSAR data. Journal of Earth System Science (2023).
3. Devaraj, S., Yarrakula, K., Martha, T.R., Murugesan, G.P., Vaka, D. S.,Surampudi, S., Wadhwa, A., Loganathan, P., and Budamala, V., Time series SAR interferometry approach for landslide identification in mountainous areas of Western Ghats, India. Journal of Earth System Science 131, 133 (2022).
4. Vaka, D. S., Rao, Y. S., and Bhattacharya, A., Surface Displacements of the 12 November 2017 Iran Iraq Earthquake derived using SAR Interferometry. Geocarto International, pp.1-14, 2019.

Preprints

1. Mandal, D., Vaka, D.S., Bhogapurapu, N.R., Vanama, V.S.K., Kumar, V., Rao, Y.S., Bhattacharya, A., Sentinel-1 SLC PreprocessingWorkflow for Polarimetric Applications: A Generic Practice for Generating Dual-pol Covariance Matrix Elements in SNAP S-1 Toolbox. Preprints 2019, 2019110393.

International / National Conference Proceedings (Peer-Reviewed)

1. Vaka, D.S., Yaragunda, V.R., Perdikou, S., Synergistic use of Multi-Temporal InSAR and Machine Learning for Dynamic Landslide Susceptibility Mapping, 2024 IEEE India Geoscience and Remote Sensing Symposium (InGARSS), 2024. (Accepted)
2. Nela. B. R., Perdikou, S., Vaka, D.S., Identifying Sandstorm-Affected Railway Networks Due to Sand Accumulation Using InSAR Coherence Change Detection Analysis, 2024 IEEE India Geoscience and Remote Sensing Symposium (InGARSS), 2024. (Accepted)
3. S. R. Chowdhury, D. S. Vaka, Y. S. Rao, A. Bhattacharya., Landslide Deformation Analysis over Joshimath region using the OpenSARLab Cloud-Based Environment, 2024 IEEE India Geoscience and Remote Sensing Symposium (InGARSS), 2024. (Accepted)
4. D. S. Vaka and S. Perdikou, "InSAR study into pre and post failure deformations of the Jagersfontein Tailings Dam," Tailings and Mine Waste 2024 - Denver, Colorado (Accepted)
5. V. L. Borgne, A. Dulmage, J. Sun, E. Davison, S. Perdikou and D. S. Vaka "Integration of multi sensing technologies for the monitoring of tailing storage facilities," Tailings and Mine Waste 2024 - Denver, Colorado (Accepted)
6. D. S. Vaka and Y. S. Rao, "Mapping Land Subsidence in Hyderabad through InSAR Time Series Analysis on the Cloud-Based OpenSARLab Platform," 2023 IEEE India Geoscience and Remote Sensing Symposium (InGARSS), Bangalore, India, 2023, pp. 1-4, doi: 10.1109/InGARSS59135.2023.10490366.
7. D. S. Vaka, Y. S. Rao and T. Singh, Surface Deformation of The 2019 Mirpur Earthquake Estimated from Sentinel-1 InSAR Data, 2020 IEEE India Geoscience and Remote Sensing Symposium (InGARSS), 2020, pp. 130-133. (Best Paper Award)
8. D. S. Vaka, V. Kumar, Y. S. Rao and R. Deo, Comparison of Various DEMs for Height Accuracy Assessment Over Different Terrains of India, IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium, Yokohama, 2019.
9. Vaka, D. S., and Rao, Y. S., Vertical Accuracy Assessment of TanDEM-X Global DEM over various Indian Terrains, URSI Asia Pacific Radio Science Conference, New Delhi, India, 2019.
10. Vaka, D. S., and Rao, Y. S., Earthquake Displacement Mapping using Interferometric Synthetic Aperture Radar, in Ananda Babu (Ed.), Fourth WCDM. Vol. 3 (pp. 226), Macmillan Publishers India Private Limited, ISBN-13: 978-9354552885
11. Ittycheria, N., Vaka, D. S., and Rao, Y. S., Time Series Analysis of Surface Deformation of Bengaluru City using Sentinel-1 images, ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., IV-5, 473-477, 2018.
12. Lal, P., Vaka, D. S., and Rao, Y. S., Mapping Surface Flow Velocities of Siachen and Gangotri Glaciers using TerraSAR-X and Sentinel-1A Data by Intensity Tracking, ISPRS Ann. Photogramm. Remote Sens.Spatial Inf. Sci., IV-5, 325-329, 2018.
13. D. S. Vaka and Y. S. Rao, Deformation of Bhuj Earthquake Area Obtained with Persistent Scatterer Interferometric Analysis of Alos L-Band Sar Data, IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium, Valencia, 2018, pp. 513-516.
14. Vaka, D. S., S. Sharma, and Rao, Y.S., Comparison of HH and VV Polarizations for Deformation Estimation using Persistent Scatterer Interferometry, ACRS 2017 - 38th Asian Conference on Remote Sensing,New Delhi, 2017.
15. Kumar, L. R., Vaka, D. S., Rao, Y. S., Mapping Land Subsidence of Krishna-Godavari Basin using Persistent Scatterer Interferometry (PSI) Technique, ACRS 2017 - 38th Asian Conference on Remote Sensing, New Delhi, 2017.

Conference Abstracts/Presentations

1. S. R. Chowdhury, S. Mishra, D. S. Vaka,, S. Maurya, Y. S. Rao, Deformation Mapping in Joshimath: A Comparative Study of InSAR Time Series Analysis With LiCSBAS, OpenSARLab, and StaMPS. ISRS-ISG National Symposium, Pune, 2023.
2. C. Ojha, D. S. Vaka, A. Pepe, Y. S. Rao, Investigating Land Subsidence Exploring Sentinel-1 Data Using MT-InSAR Technique Over Mumbai City, India. AOGS 2023, Singapore.
3. D. S. Vaka, T. Singh, and Y. S. Rao, InSAR surface deformation, geological structure and fault model of the 2019 Mirpur earthquake. XXI INQUA Congress 2023, Rome, Italy.
4. Rao, Y.S., Vaka, D.S., Ojha, C., Monitoring Slow Landslide Movement along the Northern Railway Track in Jammu & Kashmir using SAR Interferometry, ISRS-ISG National Symposium, Hyderabad, 2022.
5. D. S. Vaka, Y. S. Rao, C. Ojha and V. Kumar, Mapping land subsidence in Mumbai by Sentinel-1 InSAR time-series, FRINGE 2021.
6. S. Koleshwar, D. S. Vaka, Y. S. Rao. Ground Based Synthetic Aperture Radar Data Processing, National Symposium on Innovations in Geospatial Technology for Sustainable Development with special emphasis on NER, NESAC-Meghalaya, 2019.
7. Lal, P., Vaka, D. S., Rao, Y. S., Kumar, A. Glacier Velocity Mapping using Sentinel-2 and Landsat-8 OLI Satellite Imaging System, International Conference on Environmental Challenges and Sustainability 2018, CUJ, Ranchi, India.
8. Y. S. Rao, V. Kumar, D. S. Vaka, R. Deo, Vertical accuracy assessment of TanDEM-X WorldDEM using DGPS measurements over different terrains of India, CEOSWorking Group on Calibration and Validation (WGCV) Workshop 2017, JPL, California, USA.

Contact

Dr. Divya Sekhar Vaka
Email (Personal): vdivyasekhar@gmail.com
Email (Work): sekhar.vaka@geofem.com