The SO2 data and notification service intents to monitor SO2 emissions worldwide,
with a focus on SO2 emitted by volcanoes during eruptions. To provide
detailed maps and to easier locate SO2 emissions, a set of regions has been
defined as indicated in the map above and in the menu map on the left.
The pull-down menu on the left lists the centre coordinates of the regions.
The regions as plotted on the above map and on the menu map are 30 by 30
degrees. To facilitate following the motion of SO2 from one region into
another, the regions used in the analysis are 5 degrees wider on either
side, so that the regions overlap one another: the maps show regions of 40
by 40 degrees.
Two special regions have been defined for the polar areas: the north (south)
polar region covers all latitudes above (below) 60 degrees latitude, and
thus overlap with the top (bottom) row of rectangular regions.
Since these default regions overlap, a given volcano can appear in more than
one region. About half the volcanoes is located in two regions, some 45 in
Selecting a region from the menu on the left leads to a webpage which shows
the volcanoes in that region that have erupted since the year 1800, as
listed on the website of the Global
Volcanism Programme (GVP). The page futher tells in which of the regions
defined by the GVP the volconoes are found.
Note that the Submarine volcanoes (with summits below sealevel) are not considered very
important here, as it is very unlikely that their SO2 emissions can be
The plots shown on these pages are made with the program IDL. As can be seen
for example near the left and right axis of the world graph above, IDL has
some problems correctly colouring the continent Antarctica. The boundaries
of the countries drawn on the region maps are the political boundaries from