Geoscience Reference
In-Depth Information
worldwide, posing a significant risk for life and property loss. In Latin America,
response and recovery activities have traditionally been used to manage disasters;
however, proactive approaches that focus on immediate adaptation measures should
be implemented. While natural hazards caused by climate change cannot be pre-
vented, their risk to life and property can be greatly reduced through mitigation
planning or adaptation to reduce vulnerability. GIS technologies and remote sens-
ing data are reliable tools for mitigation planning; they can be used for identifying
hazards, surveying potential risk, assessing vulnerability, and estimating potential
losses (Bamber and Rivera
2007
). In the Andes, these technologies could be used
to develop detailed glacier inventories to assess hazardous risk and to monitor the
evolution of glacial lakes and assess their potential for outbursts.
Basic applied-research to document glacier mass, glaciated area, glacial contri-
bution to water supply, and natural hazard risk are needed. The techniques presented
in this paper could easily be implemented in the Andes. Temporal, small-scale
satellite imagery could first be used to classify glacier extent and identify sensitive
areas through change detection techniques. Large-scale, aerial photography or dig-
ital satellite imagery could then be used to perform an analysis of recession. Flow,
areal loss, volumetric loss, and potential growth of moraine-dammed lakes could all
be analyzed using simple GIS digitizing methods and DEM generation techniques.
Detailed field measurements could then be used to validate existing measurements
or examine geomorphological processes at a finer scale. Estimates could be derived
to determine how much water remains locked in a glacier or how much water could
be released in a dam failure. Susceptible areas in flood zones could be identi-
fied. Current rates of area and volume loss could be extrapolated to predict when
glaciers and water will disappear, or sophisticated climate models could be inte-
grated with GIS data to model future scenarios. In less-developed countries, where
research funds are scarcely allocated, this methodology provides a straightforward,
affordable monitoring technique. Results and possible future impacts could alter
public awareness and perceptions of local hazards and climate change. Identification
of negative impacts that affect an individual's livelihood could lead a shift to a
proactive approach in which adaptive strategies, better management, and potentially
regional polices, standards, or guidelines could be designed to manage the Andean
high mountain environment.
5.6 Conclusions
GIS, photogrammetric, field, and GPS techniques were used to assess the hazard
potential of California rock glacier. Horizontal rates of flow averaged 57 cm/yr
(
3 cm/yr) from 1983 to 1998 according to photogrammetric measurements.
Average velocities of surface debris decreased from 66 cm/yr (
±
±
8cm/yr)to
55 cm/yr (
4 cm/yr) over the 1983-1988 and 1988-1998 periods. Vertical thin-
ning (- 30 cm/yr
±
8 cm/yr) was concentrated near the head of the rock glacier from
1983 to 1998. Seven GPS measurements from 2003 to 2008 indicated an average
horizontal velocity of 52 cm/yr (
±
±
5 cm/yr).