Project 12:
Monitoring, remote sensing and early warning systems
Project Manager: James M. Strout (NGI)
Introduction
Essentially the theme of
this project is risk management, either through reduction in probability
of the hazard (prevention) or decreasing the consequences (mitigation).
The core of risk
management consists of identifying, understanding and mitigating risk by
reducing probability or consequences of hazards. The goal of the ICG
to assess, prevent and mitigate geohazards is at the heart of geohazard
risk management.
By identifying and
understanding the mechanisms of geohazards a society has as a viable
option the ability to live with risk by scaling consequence in tact with
probability. If mitigation techniques are available these may also
contribute by reducing probability.
A geohazard can be
defined to be a geological/geotechnical process which may result in
human or material losses.
How we respond is
dependent on our ability to identify the hazard, how well we understand
it, and the tools available to do something about it
The prevention of the
occurrence of a geological process is in some cases possible; for
example the dewatering of a fault zone in an unstable slope may
effectively stabilize the slope and eliminate the geohazard. However,
this is only effective if we can identify slopes that are unstable where
this is the controlling mechanism. (Otherwise we have a 'solution
without applications')
A second case may be a
process that poses a threat and which is fairly well understood and
identifiable, but is impossible to prevent. An example is a tsunami. In
this case, an early warning system may provide sufficient time to
escape, allowing us to live with the risk.
In a third case,
consider a geological process that cannot be controlled and is not well
understood. The only solution for mitigating the risk is to employ
empirical or avoidance methods, for example relocating infrastructure or
individuals out of the zone of influence.
Project goals
The focus of this
project is on the development of tools for
-
Improving the
identification of geohazards
-
Measurement systems
to reduce risk (e.g. early warning)
-
Identification of
approaches or technology that can be applied to limit or prevent
geohazards
The primary goal of the
ICG project are related to these issues (a global timeline for the
project is indicated):
Scope of work 2005
Activities to be
incorporated into the project in 2005
-
Imaging methods development adapted for the Ground-based
Interferometric SAR system (GinSAR)
-
Simple software prototyping to facilitate the processing of the GinSAR
results at ICG and among partners.
-
Development of GinSAR hardware (PhD research project)
-
Participation in international committees/organisations for remote
sensing technology for geohazard identification and monitoring (BRGM/IGOS
initiative)
-
Participation in international activities for Tsunami warning systems
-
Coordination with activities at Åkneset/Tafjord (field laboratory for
landslide geohazards)
-
Implementation of early warning system using data provided from an
existing monitoring system (Norwegian railway)
-
Administrative and technical coordination between the partners
(meetings, travel)
NORSAR
Due to
an expected flexible positioning, imaging of GinSAR data is closer to
techniques used in seismics than in air-born SAR, hence the contribution
from NORSAR. In addition to the classic Stolt migration already
implemented, Kirchhoff summation techniques or similar will be
implemented in 2005, based on existing internal software prototypes at
NORSAR. In addition, auto-focus, phase-unwrapping and simple DEM input
will be studied.
NORSAR is also contributing with a common work frame
(prototype) aimed at easily integrating Matlab codes as provided by ICG
colleagues and external sources, besides direct C++ coding. Note that
the software is already available with some of the expected
functionalities and intuitive GUI.
Emphasis is on the development of prototype software
with all necessary standard and GinSAR-adapted processing tools
(imaging, auto focus, single-look image, interferometry,
phase-unwrapping and DEM input), some of the processing algorithms being
provided by ICG colleagues or external sources as Matlab codes. The
GinSAR software will be delivered for UNIX, Linux and Windows platforms.
NGU
The main focus
will be on data mining. ICG/NGU now has a considerable amount of data on
movement that needs to be gone through in great detail to isolate
unusual behavior. It is easy to create a map showing average velocity
and see things that are moving constantly, but many areas move
intermittently and this gets hidden in the data.
The
challenge is to find a method to identify these points within hundreds
of thousands of data points. Some preliminary work on developing
visualization tools has been done; this work may be continued in
cooperation with geostatistics experts abroad.
Fieldwork will be performed in Drammen, Åkeneset and in Trondheim. The
work in Drammen will provide support for the analysis of the existing
data covering Drammen. Corner reflectors will be set up at Åkneset to
test the LISA ground-based SAR system. Finally, resistivity measurements
and reflection seismic in Trondheim are considered to obtain additional
data for identifying the large movements detected in the Eberg
neighborhood as soon as the snow clears. This is supported by Trondheim
kommune who is also doing some detailed surveying in the area.
NTNU/UIO
The activities
at the academic partners will primarily be the support of the PhD
studies as well as for travel or other expenses connected to
participation in the project.
NGI
The work at NGI will consist of
- Implement a case
study of an early warning system (Rauberget slide area for the
Norwegian railway system)
- Participation in
the IGOS geohazards theme (international activity)
- Follow up of the
international tsunami initiatives
- Administration of
the project
NGI instrumentation
division has developed a monitoring system to detect earth slides
encroaching on a railroad line. The monitoring technology is based on
the use of geophones. NGI and the Norwegian railway have offered access
to and use of the data collected to be used as input to a case study.
The case study would involve a basic evaluation of data (identification
of what elements in the data constitutes a slide event), reliability of
the determination (elimination of noise not related to sliding), and the
criteria to establish alarms responding to the event. Note that the
case study will not involve the monitoring system itself, the case study
assumes data is supplied in a useable and accessible format.
A new effort in the
European community (IGOS - geohazards) has been initiated to work with
the application of satellite imaging and radar data for detecting
geohazards. The developments of the IGOS-Geohazards initiative will be
followed under this theme, including participation in relevant IGOS
workshops in June 2005.
The tsunami disaster
of 2004 has also generated a number of initiatives regarding tsunami
early warning systems; considerable time is also invested in following
up the initiatives to position the ICG as a participant in the
national/international activities.
Long term plans
(2006 - 2008)
- Theme:
Identification and measurement
- Theme: Tools for
evaluation/processing of complex data
- Theme: Case study
in prevention and mitigation
Theme:
Identification and measurement
The focus of the development of
measurement technology will be on remote monitoring using geophysical
methods, in particular inSAR and GinSAR. Historical satellite data
exists from 1991. R&D work on traditional measurement technology itself
(e.g. development of a sensor) will not be considered, however the
implementation of sensor systems utilizing traditional technology to
address geohazard issues are a natural component in this project.
GinSAR and inSAR are complementary because inSAR (satellite based) data
is not available everywhere, while GinSAR is a portable system that can
be deployed at specific locations as needed. GinSAR can provide better
resolution, and may be configured to capture horizontal displacements as
well as vertical. InSAR provides the capability to monitor large
regions and inaccessible areas, but has lower resolutions and cannot
capture predominantly horizontal displacements and may not be applicable
in areas with very steep slopes.
-
GinSAR - The goal of the work on Ground based Interferometric
Synthetic Aperture Radar (GINSAR) technology is to develop equipment
for measuring small displacements of rock slopes, Spin off technology
is also available, for example for monitoring of clay slopes and snow
accumulation for avalanche warning. This is the focus of the PhD
stud | 
