This document discusses various techniques for monitoring landslides, including remote sensing, photogrammetry, ground-based surveying, GPS, and geotechnical methods. Remote sensing techniques discussed include synthetic aperture radar (SAR), interferometric SAR (InSAR), and RADAR systems which use radio waves to detect ground movement. Photogrammetry allows interpretation of aerial photos to identify landslides. Ground surveying employs techniques like triangulation and leveling. GPS provides location and velocity data through satellite signals. Geotechnical sensors monitor deformation underground through extensometers, inclinometers, piezometers, and other instruments.

1. LANDSLIDE MONITORING
SYSTEMS & TECHNIQUES
MANEEB MASOOD
M.Tech.Part-1(15152010)

2. Introduction
• Landslides are downslope movements of rock,
debris or earth under the influence of gravity.
• Landslides are one of the most significant
hazards in terms of socio-economic costs,
threatening infrastructures and human
settlements.
• The monitoring of their surface displacement is
thus crucial for the prevention and forecast of
landslides.

3. Systems and Techniques for
Landslide Monitoring
• 1. Remote sensing or satellite techniques with
space-derived information.
• 2. Photogrammetric techniques
• 3. Ground-based conventional surveying
techniques
• 4. GPS techniques
• 5. Geotechnical techniques

4. Remote sensing techniques
• SAR(Synthetic Aperture Radar) Imagery
• InSAR(Interferometric Synthetic Aperture
Radar) techniques
For landslides,
Ground based;
Satellite based.

5. • RADAR (Radio Detection and Ranging)
Satellite sends a pulse of electromagnetic energy into space
that reflects upon encountering the Earth surface.
(A radar transmits radio waves or microwaves that reflect from any object in
their path. A receive radar, which is typically the same system as the transmit
radar, receives and proesses these reflected waves to determine properties of
the objects)
• SAR (Synthetic Aperture RADAR)
Larger antenna = better resolution -> SAR uses the spacecraft
motion to simulate an extremely long antenna.
• Interferometric
Difference 2 phase images of the same area at different times
to detect ground motion = interferogram.
Combine many interferograms to produce amean velocity map
in which the color shows the speed at which the ground is
moving.
InSAR (Interferometric Synthetic Aperture RADAR)

7. Berkeley slow moving landslides
InSAR

9. InSAR at the scale of country

10. Photogrammetric techniques for
landslide monitoring
• The interpretation of aerial photography has
proven to be an effective technique for
recognizing and delineating landslides.
• It is an effective technique for recognizing and
delineating 3D overview of the terrain from
which the interrelations of photography,
drainage, surface cover, geology materials, and
human activities on the landscape can be viewed
and evaluated.

11. Ground-based conventional surveying
techniques for landslide monitoring
• Triangulation
• Levelling
• Monitoring by Total Stations

12. Using Global Positioning System
techniques in landslide monitoring
• GPS provides specially coded satellite signals that
can be processed with a GPS receiver, enabling the
receiver to compute position, velocity and time.
• A minimum of four GPS satellite signals are
required to compute positions in three dimensions
and the time offset in the receiver clock.
• Accuracy and precision of data increases with more
satellites.

13. GPS Trilateration
With signals from two satellites, the
receiver can narrow down its location to
just two points on the earths surface.
Were the two circles intersect.

14. GPS Trilateration--
cont.
• Knowing its distance
from three satellites, the
receiver can determine
its location because there
is only two possible
combinations and one of
them is out in space.
• In this example, the
receiver is located at b.
• The more satellite that
are used, the greater the
potential accuracy of the
position location.

15. GPS Techniques
(a)fast-static(FS)
(b)real time kinematics(RTK)

16. Special considerations for monitoring
• The selected targets must reflect the mean
behaviour of the surrounding area.
• Tree canopy, buildings and other obstacles that
could restrict the reception of the satellite signal
should be avoided.
• To mark the station points, it is advisable to use
sturdy stations.
• It is convenient to include within the control
network several fixed points outside the landslide
area.
• To strengthen the results, it will also be helpful to
use different methods and repeat the observations.

17. Geotechnical techniques for landslide
monitoring
• Geotechnical sensors are used extensively in the
monitoring of structures.
• The main geotechnical sensors used for
deformation monitoring include; extensometers,
inclinometers, piezometers, strain meters,
pressure cells, geophones, tilt meters and crack
meters.

18. • Inclinometers
They are instruments installed in boreholes
drilled within the landslide mass.
They measure the curvature of initially straight
boreholes, thus detecting any change in
inclination of the borehole casing.

19. • Extensometers
Measure the axial displacement between a number
of reference points in the same measurements axis.
They can be installed within a borehole or on the
slope surface.
The wire extensometer is widely used typically
measuring baselines of up to 80 m in length with a
accuracy of ± 0.3 mm per 30 m.
The actual accuracy depends on the temperature
corrections and on the quality of the installation of
the extensometer.
Maintaining a constant tension throughout the use
of the wire extensometer is very important.

20. • Piezometers
Many landslides are triggered by slope saturation
following heavy rainfall.
Measurement of pore water pressures and
piezometric levels form an important part of
slope stability analysis.
Threshold levels can be defined to provide early
warning of conditions that may lead to
catastrophic failure.

21. • Geophones
They are devices that can measure vibration
associated with movement.
They can detect landslides on the basis of
frequency composition, amplitude, and duration
of the vibration signal.

22. References
• Using Global Positioning System techniquesin landslide monitoring
Josep A. Gili a,b,*, Jordi Corominas a, Joan Rius a Department of Geotechnical Engineering and
Geosciences, Technical University of Catalonia, Jordi Girona 1–3,Edifici D-2, 08034 Barcelona, Spain
b Institute of Geomatics, Barcelona, Spain
Received 24 November 1998; accepted for publication 8 July 1999
• Traditional and Innovative Techniques for Landslide Monitoring:
dissertation on design criteria Paolo Mazzanti1, Giorgio Pezzetti2
1NHAZCA S.r.l. & Department of Earth Sciences, Università di Roma “Sapienza”, Rome, Italy
2FIELD S.r.l. Bergamo, Italy
• Landslide monitoring with InSAR
E. Chaussard, R. Bü rgmann,
J. Cohen-Waeber, B. Delbridge (University of California Berkeley)
• Landslide deformation monitoring with ALOS/PALSAR imagery: A D-InSAR
geomorphological interpretation method Romy Schlögel ⁎, Cécile Doubre, Jean-Philippe Malet,
Frédéric Masson Institut de Physique du Globe de Strasbourg, CNRS UMR 7516, Université de
Strasbourg/EOST, 5 rue Descartes, 67084 Strasbourg, Cedex, France
• Landslide monitoring by combining of CR-InSAR and GPS techniques
Wu Zhu a,c,⇑, Qin Zhang a,b, XiaoLi Ding c, Chaoying Zhao a,b, Chengsheng Yang a,b,
Feifei Qu a, Wei Qu a,b
a College of Geology Engineering and Geomatics, Chang’an University, No. 126 Yanta Road, Xi’an 710054,
China. bKey Laboratory of Western China’s Mineral Resources and Geological Engineering, Ministry of
Education, No. 126 Yanta Road, Xi’an 710054, China
c Department of Land Surveying and Geo-Informatics, Hong Kong Polytechnic University, Hong Kong, China
Received 19 November 2012; received in revised form 21 November 2013; accepted 3 December 2013
Available online 10 December 2013