Mouginis-Mark, Peter 
  
2 REMOTE SENSING CAPABILITIES 
Much progress has been made in the use of remote sensing observations of active volcanic processes during the 
1990’s, and further substantive developments are to be expected over the next few years as next-generation spacecraft 
are launched by the United States, Europe, Canada, and Japan. For instance, now that the Landsat-7 spacecraft has 
become an operational Earth observatory, there is a long term plan for the acquisition of data via routine imaging of all 
of Earth’s land surface [Goward et al., 1999]. As a result, many volcanoes around the world are now being imaged on a 
routine basis for the first time. The other recently-launched U.S. spacecraft (Terra) is the first part of the Earth 
Observing System (EOS) and, at the time of writing, has just started to return test data sets. 
Research into the volcanological uses of EOS data has been conducted for almost a decade [Mouginis-Mark et 
al., 1991], and similar preparations have been made for the use of other orbital remote sensing data. For instance, 
Landsat-7 and Terra will be joined in the next few years by the highly capable Environmental Satellite (ENVISAT) and 
the Advanced Earth Observing Satellite 2 (ADEOS II) spacecraft, flown by Europe and Japan respectively. Both 
ENVISAT and ADEOS II carry visible- and infrared-wavelength sensors, and ENVISAT will also have an imaging 
radar system. Dedicated imaging radar missions, such as RADARSAT-2 and the advanced land observing system 
(ALOS), will be flown in the 2001—2004 timeframe by Canada and Japan, respectively. 
There have been several reviews of satellite remote sensing of volcanoes (e.g., Francis, 1989; Mouginis-Mark 
and Francis, 1992; Mouginis-Mark et al., 1993; Rothery and Pieri, 1993; Self and Mouginis-Mark, 1995; Francis et al., 
1996; Sparks et al., 1997; and Oppenheimer, 1998). These earlier reviews have tended to focus on individual sensors, 
wavelength regions, or techniques. But each volcano has a unique history of activity and individual eruptions can 
evolve over time periods ranging from hours to more than a decade, so that many volcanic hazards must be studied via a 
range of techniques. Fortunately, many aspects of an eruption can now be studied at some level using either airborne or 
spaceborne remote sensing techniques. This paper illustrates some of these techniques and their relevance for volcano 
hazard monitoring and recovery. 
3 EXAMPLES FROM RECENT ERUPTIONS 
3.1 Hawaii, 1983 - 2000 
Kilauea volcano, Hawaii, has been in near continuous eruption since January 1983. It has therefore proven to be 
an excellent study area to develop diverse remote sensing methods. For instance, hyperspectral techniques for the 
analysis of lava flow temperatures (Flynn and Mouginis-Mark, 1992), the mapping of total thermal flux from active 
lava flows (Flynn et al., 1994; Harris et al., 1998), the estimation of lava production rates from interferometric radar 
(Zebker et al., 1996), mapping the flux rate of sulfur dioxide using thermal infrared images (Realmuto et al., 1997), and 
the analysis of topographic change via comparison of digital elevation models (Rowland et al., 1999), have all been 
developed at Kilauea. Routine automated methods for frequent monitoring the thermal output of the volcano (Harris et 
al., 1997, 2000) using geostationary satellite data have also been developed at Kilauea. 
This wide range of remote sensing data sets has also provided an excellent opportunity for the use of Kilauea and 
Mauna Loa volcanoes as calibration and validation sites for spaceborne sensors. For instance, the summit of Mauna 
Loa volcano is an ASTER calibration target for the Terra mission, while digital elevation data collected by the 
TOPSAR airborne radar (Rowland et al., 1999) will also be used to validate measurements made by the Shuttle Radar 
Topography Mission (SRTM) and the Vegetation Canopy Lidar (VCL) mission. 
3.2 Galapagos Islands, 1998 
The September 1998 eruption of Cerro Azul volcano in the Galapagos Islands provided an excellent opportunity 
to monitor an on-going eruption in a part of the world where field logistics were difficult and expensive (Mouginis- 
Mark et al., 2000b). The GOES-8 weather satellite collected 520 visible and thermal daytime images, and 815 
nighttime thermal images, during the 36-day eruption of Cerro Azul. A sub-set of these images that cover the onset of 
the eruption on September 15™ 1998 is shown in Figure 2 to illustrate the high temporal resolution that can be obtained 
from geostationary orbit. Numerous features of the eruption were observed in the GOES data, including eruption 
plumes and their dispersal patterns, the thermal anomalies due to intra-caldera activity, and the active lava flows on the 
eastern flank. Particularly important was the use of the GOES data to obtain accurate times for the start and termination 
of the eruption, as well as the identification of the location of the active vents both within and outside the summit 
caldera. Retrospective analysis of field observations also indicates that other aspects of the eruption were seen in the 
GOES data, including smoke from burning vegetation at the edge of the active flows, and haze plumes produced from 
degassing at the vents. 
  
906 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 
  
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