Presentation about InSAR application in earthquake studies.

1. Presented
By
Priyanka Dhar

2. ❖ INTRODUCTION
❖ SIMPLISTIC VIEW OF InSAR
❖ TYPES OF INTERFEROMETRY
❖ DERFORMATION MAPPING WITH InSAR
❖ INTERFEROGRAM GENERATION
❖ INTERPREATING TECHNIQUE OF INTERFEROGRAM
❖ OVERVIEW OF GeoGateway IN EARTHQUAKE STUDY
❖ REFERENCES

3. INTRODUCTION
• An Earthquake is the sudden shaking of Earth surface caused by
releasing of energy in the Earth’s lithosphere that creates seismic waves.
• Earthquake disaster can cause loss of life, damage property.
• To alleviate the adverse impact of
earthquakes, various kinds of geophysical
techniques are utilised for earthquake
mechanism research.
• Ground or space based techniques
such as seismographs which record the
seismic wave, levelling measurements of
relative deformation of the surface and
the GNSS such as GPS that offers vertical
and horizontal movement information are
commonly used to monitor earthquakes.

4. • Synthetic Aperture Radar (SAR) imagery is produced by reflecting radar
signals off a target area and measuring the two way travel time back to the
satellite.
• The SAR interferometry technique uses two SAR images of the same
area acquired at different times and "interferes" (differences) them, resulting
in maps called interferograms that show ground-surface displacement
(range change) between the two time periods.
• View of SAR phase
Phase of image 1
2
1
Phase of image 2
SAR PHASE

5. TYPES OF INTERFEROMETRY
• There has two main classes of interferometry
✓ Cross- track Interferometer
✓ Along- track Interferometer
CROSS- TRACK IROMETNTERFEER ALONG- TRACK INTERFEROMETER

6. DEFORMATION MAPPING WITH InSAR
InSAR Phase
difference

7. INTERFEROGRAM GENERATION
• Interferograms are maps of relative ground-surface change that are
constructed from InSAR data to help scientists understand how tectonic or
human activities, such as groundwater pumping and hydrocarbon production,
cause the land surface to uplift or subside.
• For generating Interferogram need two radar images.
Line of sight (LOS) SOURCE : GeoGateway _user_Guide

8. INTERPREATING INTERFEROGRAMS
There has 3 simple steps to interpreat a interferogram.
Step 1
In InSAR fringes count the number between two
points on the interferogram, where one fringe is
denote one complete color cycle (i.e. red, orange,
yellow, green, blue, purple).
Step 2
Multiply the number of fringes by 28 mm,
because there are 2 fringes, the maximum
displacement (at the bottom of the bowl),
is 56 mm.
SOURCE : nasa.gov.in

9. INTERPREATING INTERFEROGRAM
Step 3
If the ground moved closer (uplift) or
farther away (subsidence) from the satellite
by matching how the colors change
between the two points with the InSAR
scale bar. If the range is increase (i.e. red,
orange, yellow, green, blue, purple) it
indicates subsidence, and a decrease in
range indicates uplift.
SOURCE : nasa.gov.in

10. OVERVIEW OF Geo Gateway IN
EARTHQUAKE STUDY
❑ Select Data Products
SOURCE : GeoGateway _user_Guide

11. ❑ Displaying Individual Lines
SOURCE : GeoGateway _user_Guide

12. ❑ Line of Sight Tools
SOURCE : GeoGateway _user_Guide

13. REFERENCES
▪ InSAR Technique for Earthquake Studies By Youtian Liu, Geoscience and Earth
Observing Systems Group (GEOS) School of Civil and Environmental Engineering Faculty
of Engineering, The University of New South Wales Sydney, NSW 2052, Australia August
2015, DOI: 10.1080/19475683.2015.1068221
▪ Massonnet, D. et al. The displacement field of the Landers Earthquake mapped by
radar interferometry. Nature 364, 138–142 (1993).
▪ “How satellite InSAR has grown from opportunistic science to routine monitoring over
the last decade”- Juliet Biggs & Tim J. Wright , Nature Communications volume 11,
Article number: 3863 (2020)
▪ https://www.usgs.gov/centers/ca-water-ls/science/interferometric-synthetic-aperture-
radar-insar InSAR- USGS
▪ Introduction to SAR Interferometry- Eric Fielding, http://arset.gsfc.nasa.gov
▪ The global CMT project 2004–2010: Centroid-moment tensors for 13,017 earthquakes.
EKSTRÖM, G., NETTLES, M. & DZIEWOŃSKI, A. M. 2012. Physics of the Earth and
Planetary Interiors, 200–201, 1-9.
▪
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.researchgate.net%2Ffigure
%2FPrinciple-of-the-InSAR-techniques-the-phase-difference-observed-by-comparing-two-
SAR_fig1_342916517&psig=AOvVaw3AzRY5NWDJRu-
MNwF6i_SC&ust=1618847476153000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCL
CRxPiSiPACFQAAAAAdAAAAABAD
▪ GeoGateway_User_guide