Jökull - 01.12.1992, Síða 82

8. mynd. Vatnshæðarlínurit úr mæli nr.
162 í Jökulsá á Fjöllum. FUaup senni-
lega úr Hveradal.
-Hydrograph ofa jökulhlaup inJökulsá
á Fjöllum.
Helgi Bjömsson og Páll Einarsson 1990. Volcanoes
beneath Vatnajökull, Iceland: Evidence from radio
echo-sounding, earthquakes and jökulhlaups./öl-
ull 40, 147-168.
Höskuldur Jónsson 1988. Ný brú yfir Fremri-Emstruá.
FréttabréfF.Í. 13, 6. árg. bls. 4.
Sigurjón Rist og Sigurður Þórarinsson 1970. Annáll
um jökulhlaup. Jökull 20, 88-89.
SigurjónRist 1973. Jökulhlaupaannáll 1971, 1972 og
1973. Jökull 23,55-60.
SigurjónRist 1976. Jökulhlaupaannáll 1974, 1975 og
1976. Jökull 26, 75-79.
Sigurjón Rist 1981. Jökulhlaupaannáll 1977, 1978,
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SUMMARY
The paper describes jökulhlaups that have oc-
curred in Iceland during the period 1984-1988, to
the authors1 knowledge. The jökulhlaups originate
from ice dammed marginal lakes or subglacial lakes
of geothermal areas. Marginal lakes burst mainly dur-
ing the summer while the other type of jökulhlaups
can occur any time of the year. Most of them are more
or less periodical.
The National Energy Authority monitors 24 glacial
rivers, 5 of them render jökulhlaups periodically. A
few more glacial rivers are monitored sporadically,
especially during jökulhlaups.
A total of 27 jökulhlaups, including 10 from hy-
drothermal areas, are accounted for. Dates, volume
and/or discharge are given for 16 events. Hydrographs
of 6 different jökulhlaups are shown.
None of these jökulhlaups are considered to be
exceptional in any way, but two bursts in the river
Jökulsá á Fjöllum during the winters 1985 and 1987
were unexpected.
80 JÖKULL, No. 42, 1992