Jökull - 01.12.1972, Blaðsíða 29

Infrared Emission from Kverkfjöll Subglacial Volcanic
and Geothermal Area, Iceland’
JULES D. FRIEDMAN,
UNITED STATES GEOLOGiCAL SURVEY, WASHINGTON, D.C.
RICHARD S. WILLIAMS JR.,
UNITED STATES GEOLOGICAL SURVEY1 2, WASHINGTON, D.C.
SIGURDUR THORARI NSSON,
UNIVERSITY OF ICELAND, REYKJAVIK
GUDMUNDUR PÁLMASON,
NATIONAL ENERGY AUTHORITY, REYKJAVÍK, ICELAND
ABSTRACT
Aerial infrared surveys' with an optical-
mechanical line scanner using an indium anti-
monide solid-state detector were carried out
over the Kverkfjöll massif on the north side
of Vatnajökull in 1966 and 1968. Thermal
anomalies of the area, their relationship to pre-
viously known geologic features, and changes
obserued between 1966 and 1968 were recorded
on film and videotape. Signal amplitude slices
showing incremental steps in infrared emission
from the earth’s surface reveal at least 120
points of geothermal activity in t.he partly sub-
glacial Hveradalur (solfatara valley) of West
Kverkfjöll. Infrared images of 1966 and 1968
show the night position of a thermal equilibri-
um point for warm melt water emerging from
a portal in the snout of Kverkjökull outlet
tongue. The melt-water stream yielcls 20 x 10fí
1) Presented in part at the symposium, Vol-
canoes and their Roots, International Associa-
tion of Volcanology and Chemistry of the
Earth’s Interior, Oxford, England, September
11, 1969.
2) Formerly Air Force Cambridge Research
Laboratories, Bedford, Massacliusetts.
Publication authorized by the Director, U. S.
Geological Survey.
caljsec advective h.eat flow from a hidden sub-
glacial geothermal source which may have a
total thermal yield of 300—540 xl0fí cal/sec.
The energy expended in forming the 620 X 590
m Kverkfjöll ice cauldron is estimated to have
been 1.2 x 1023 ergs; infrared data indicate
continuecl but diminishing thermal activity on
the cauldron rims between 1966 and 1968.
Aerial infrared surveys using an optical-
mechanical line scan device and aerial carto-
graphic cameras with Plus X (Kodak type 5401)
ancl Infrared Ektachrome Aerographic (Kodak
type 8443) film were conducted in August 1966
ancl August 1968 over the Kverkfjöll reentrant
on the north side of Vatnajökull (Figs. la and
lb). The surveys, separated by a two-year
interval, were designed as an experiment in
monitoring changes in thermal activity at this
partly subglacial volcanic. and geothermal area
by an aerial infrared technique. The present
report gives a brief discussion of the thermal
and related features identified and delineated
by the infrared method, their relationship to
previously known geologic features of the area,
and changes observed between 1966 and 1968.
Tlie ice-covered Kverkfjöll massif (Fig. 2)
occupies a large part of the reentrant between
JÖKULL 22. ÁR 27