tanbul 2004
> WIR band,
S Or several
le by CNES
Valorization
the Swedish
] evaluation
| Board of
Adaptive
olution data
Aulti-Sensor
ns, Remote
y.
, Fusion of
mean and
ngs of the
zarth Data
otely sensed
s, EARSeL-
1 in remote
Germany,
cuments/O
ensor fused
nd borders
ote Sensing,
99. A local
ig data with
pplications,
ote Sensing,
Modulation:
ving spatial
72.
assification
id spectral
( IRS-1C),
ite Sensing,
images of
chives of
7-4-3 Wo,
VALIDATION OF SPOT-5 SATELLITE IMAGERY FOR GEOLOGICAL HAZARD
IDENTIFICATION AND RISK ASSESSMENT FOR LANDSLIDES, MUD AND DEBRIS
FLOWS IN MATAGALPA, NICARAGUA
5
Y ar Eus s ; = i ; 5
Y. Haeberlin *', P. Turberg ”, A. Retière ©, O. Senegas *, A. Parriaux t
? UNOSAT, CERN, IT/DI/UN Bát. 6402, 1211 Geneva 23, Switzerland — (yves.haeberlin, olivier.senegas)@cern.ch
b GEOLEP, EPFL, 1015 Lausanne, Switzerland — (Pascal. Turberg, Aurele.Parriaux)@epfl.ch
* UNOSAT, UNITAR-UNOPS, Chemin des Anémones 11-13, 1219 Châtelaine, Geneva, Switzerland —
alainr@unops.org
KEY WORDS: Remote Sensing, Hazards, Developing Countries, Geology, Landslides, Identification, Monitoring
ABSTRACT:
This analysis addresses the suitability and potential for the use of high-resolution SPOT-5 remote imagery for geological hazard
identification and risk assessment in Matagalpa, Nicaragua. SPOT-5 products are complementary tools in the process of risk analysis
and in combination with digital elevation models (DEMs) are particularly helpful for determining large, kilometer-sized hazardous
phenomena for watersheds. At Matagalpa, a pseudo-color 2.5 m SPOT-5 image draped over a DEM for 3D simulation is tailored for
mapping landslide scarps and recent debris flow deposits at scales up to 1:25°000, but is inappropriate for identifying mud flow
events. In contrast, the input of SPOT-5 derived products to hazard susceptibility mapping is limited, since among the prime factors
controlling terrain instability (slope, geology, hydrography), only information about geological lineaments can be recovered. A few
second-order risk factors, such as barren soils and deforested areas can be extrapolated from SPOT-5 land cover and change
detection maps. For vulnerability issues, SPOT-5 images are a relevant source of spatial information on threatened elements
(settlements, road infrastructure), if there are neither quality, nor current maps of the area available.
1. INTRODUCTION
After the devastating damage from Hurricane Mitch in late
October 1998, the region and city of Matagalpa (Fig. 1),
Nicaragua, was in need of considerable humanitarian relief and
aid for reconstruction. Due to the lack of appropriate
Geographic Information System (GIS) and Resource Centers,
immediate assistance to the victims and their resettlements were
carried out based on poorly informed decisions that have
increased the pressure on weak municipal services, such as
water supply and road maintenance, and resulted in deeper
vulnerability to disaster risk. In order to address the situation,
the Municipality of Matagalpa has requested financial and
technical assistance to the Canton of Geneva, Switzerland that
in the context of the United Nations Strategy for Disaster
Reduction (ISDR) sponsored the UNOSAT assistance for the
establishment of the Geographic Information Centre for the
watershed of the Rio Grande of Matagalpa (CIGMAT), as a key
resource for further geological and hydrological risk
assessment, and integration of risk management in urban and
rural planning. UNOSAT is a service of the United Nations
Institute for Training and Research (UNITAR) implemented by
the United Nations Office for Project Services (UNOPS),
dedicated to provide satellite imagery and GIS services to
humanitarian organizations and local communities in
developing countries.
In this context, as partner of the French Space Agency (CNES),
Spot Image, the European Space Agency (ESA) and the
European Centre for Particle Physics (CERN), UNOSAT
accepted to participate in cooperation with CIGMAT to the
SPOT-S validation program by testing in close collaboration
with the Laboratory of Geology (GEOLEP) of the Swiss
Federal Institute of Technology (EPFL), the suitability and
potential of SPOT-5 data in combination with digital elevation
models (DEMs), Synthetic Aperture Radar (SAR) land
deformation data, topographic maps and a geological GIS
database for natural hazard mapping in the Matagalpa area,
using (a) a visual and semi-automatic approach for phenomena
identification and monitoring, and (b) the multi-risk factor
evaluation methodology developed by EPFL/GEOLEP. For
end-users that need reliable and cost-effective master plans, this
document also presents a critical analysis and review of SPOT-
5 imagery for the generation of vulnerability maps.
In the Matagalpa region, no remote sensing data has yet been
integrated for monitoring the common geological hazards, such
as landslides, mud flows and debris flows. The available
geohazard studies, which were undertaken in the post-Mitch
period, are grounded on either field observations (Carrefio and
Barreto, 2000; Havlíéek et al, 2002) or aerial photo
interpretations (Cannon et al., 2001). Carreño and Barreto
(2000), based on a cartographic analysis of the areas affected by
Mitch established a hazard susceptibility map as a decision tool
for territorial planning. Cannon et al. (2001), in a contribution
dedicated to landslide response to Hurricane Mitch rainfall
proposed a detailed inventory of the 1998 active mud/debris
flows and landslides, including a delimitation of their initiation
points and run out areas. Finally, Havlièek et al. (2002) raised a
set of three comprehensive 1:50'000 geological maps,
corresponding with the Instituto Nicaragüense de Estudios
Territoriales (INETER) Matagalpa topographic sheet, and also
with our study area (Fig. 1). They produced (a) a geological
map of the underlying volcanic units; (b) a geomorphological
map, reporting the quaternary formations, the lateritic soils and
the peneplanation levels, and; (c) a hazard map, with the
delimitation of occurred movement types (landslides, rock falls,
mud/debris flows, including phenomena related to Hurricane
Mitch), and the location of structural, morphological and
tectonic features prone to natural hazards. All the above
