Environmental Engineering Reference
In-Depth Information
typically span hundreds of years; however, some volcanoes can erupt, albeit at
somewhat less intensity, into the troposphere (e.g. Mt. Etna) or even directly reach
the tropopause (e.g. Kliuchevskoi Volcano) with almost annual regularity. Surface
effects (e.g. lava flows, ash falls, pyroclastic flows, lahars, debris flows) can occur at
relatively small characteristic spatial scales (e.g. of order 1
-
100 m for dynamic cores;
of order 1
-
10 km in areal extent), and can occur on timescales of just a few minutes
(especially pyroclastic
flows); or they can can persist for months (e.g. Mauna Loa
1984 eruption) or for years (e.g. Kilauea Pu
o, since 1983 and ongoing). Ancient
eruptions (e.g. Yellowstone Lava Creek eruption, 640 Ka BP; Toba eruption,
'
uO
'
73 Ka
BP; Santorini eruption, 3.6 Ka BP; Deccan Traps eruptions, 60
-
68 Ma BP; Siberian
Traps eruptions,
~
250
-
251Ma BP; Altiplano
-
Puna ignimbrites, 10
-
11Ma BP), and
even more recent large eruptions (e.g. Krakatoa, 1883; Tambora, 1812
-
1814;
Ksudach, 1907; Katmai, 1912), dwarf our contemporary experience with respect to
the application of remote sensing techniques.
Fortunately, remote sensing has undergone astonishing growth in platforms
(now including unmanned aerial vehicles (UAVs)) and spectral range. In addition,
new large (of order 10
2
~
-
10
3
Tbytes) online digital archives of multi-to-hyper
spectral satellite images exist, spanning the 40 years since the
first Landsat images
were acquired, including digital elevation models for much of that time (e.g.
http://
ava.jpl.nasa.gov
). Thus, there are now detailed systematic synoptic data document-
ing volcano emissions and deposits over that period.
In this chapter, I provide a catalog of remote sensing strategies and techniques
as related to the characteristics of contemporary volcanic activity. Hopefully,
examination of current approaches will suggest areas of improvement, as well as
strategies to observe and study the largest geologically known eruptions, which
modern humans have yet to directly experience, but which lie in our future, and
which will have profound implications for weather and climate.
9.2 Worldwide capability to detect and monitor volcanic
emissions from satellites and aircraft
9.2.1 Orbital observations
Modern orbital satellite remote sensing techniques have been used to collect image
data over volcanoes for many years (e.g.
Table 9.1
). Orbital multispectral missions
typically fall into two classes:
missions, with
multispectral observations often being the most useful for volcanological applica-
tions. Most of these missions have involved national or multi-national civilian
assets and data access is relatively economical for researchers. Commercial
broadband or panchromatic data can provide very high spatial (1
-
5 m/pixel) and
“
mapping
”
missions and
“
sampling
”
