Jökull - 01.01.2014, Blaðsíða 125

Society report
Real-time monitoring of volcanic eruptions in Iceland
2004–2014 using satellite images
Ingibjörg Jónsdóttir,1 Þorvaldur Þórðarson,1 Ármann Höskuldsson1 og Þorsteinn Sæmundsson2
1Jarðvísindastofnun Háskólans, Öskju, Sturlugötu 7, 101 Reykjavík; ij@hi.is
2Raunvísindastofnun Háskólans, Öskju, Sturlugötu 7, 101 Reykjavík
Real-time monitoring of volcanic eruptions in Ice-
land 2004–2014 from satellite images
Real-time monitoring of volcanic eruptions in Ice-
land, using satellite remote sensing, has expanded
during the last decade. Availability of satellite images
has increased extensively in the last few years, with
improved geometric, radiometric, and time resolution,
in addition to shortened delivery time. This paper pro-
vides an overview and a brief historical perspective of
the topic.
Data from scanners and sensors in satellites can
provide important information on geological events
and processes. As with any other sources, such data
rarely tells the entire story, but can on many levels
give different perspectives, provide an overview in re-
mote or inaccessible regions and create a timeline of
development or changes. The purpose of carrying out
real, or near-real time monitoring of a volcanic erup-
tion can be: i) To position sites of increased temper-
ature, related to geothermal regions, and identify new
vents or fissures. ii) To clarify timing of events, or at
least narrow the time gap. iii) To indicate hazard due
to lava, flooding, plume or pollution related to erup-
tions. iv) To provide information to field groups, for
ensuring safety and to locate sites of sampling lava,
tephra, and water. v) To estimate activity, effusion
rates and velocity of lava flow. vi) To map the extent of
lava, eruption plume and/or tephra fall. vii) To study
landscape within lava; lava types, roughness and vol-
ume. The list is not complete, and is dependent on the
properties of available satellite data at a given time
and the nature of the event.
Brief historical perspective of remote sensing of
eruptions in Iceland
Over 20 volcanic eruptions have occurred in Iceland
since weather satellites became operational in 1960;
marking the beginning of regular Earth observations
from space (Lillesand et al., 2008; Harris, 2013; Thor-
darson and Höskuldsson, 2014). Some of the events
were captured on satellite images at the time, the
NIMBUS-II image of the volcanic island Surtsey in
1966 being a fine example of one of the earliest events
(Williams et al., 1967; Harris, 2013), whilst others
could yet be discovered on images that have recently
become available through processing of old material
(NDRP 2014, NASA Earth Explorer 2014). Figure
1 illustrates the time span of the satellites, and as-
sociated data, that have been directly and indirectly
available to scientists during this period, with a short
overview over volcanic eruptions in Iceland. It should
be noted here that the eruptions, even at the same vol-
cano, were quite variable in duration, type and mag-
nitude, and will not be discussed here in any detail.
The potential of using satellite images for geo-
logical studies seemed clear to scientists very early
on, even detecting large features such as the caldera
in Bárðarbunga with a LANDSAT-1 image on Jan-
uary 31st 1973 (LANDSAT was then called ERTS-1)
(Thorarinsson et al., 1973; Williams and Thorarins-
son, 1973; p. 90 this volume). The eruption in Eldfell
on Heimaey, off S-Iceland, was caught on LANDSAT-
5 on March 9th 1973, though it is not clear if the
image was available to researchers at the time. Dur-
ing the eruptions in Krafla, frequent aerial surveys
JÖKULL No. 64, 2014 125