Jökull - 01.06.2000, Blaðsíða 61

Páll Einarsson and Bryndís Brandsdóttir
22˚W 20˚W 18˚W
63˚ 30'N
64˚ 00'N
64˚ 30'N
25 km0
SB
SK
HE
SP
SH
LV
HB SL
AR
SE SKO
MV
M
TH
Ey
El
LJVA IR
KK
KVHL
HF
MI
Figure 1. Index map of central volcanoes, volcanic systems and seismic stations used in this study. All seismo-
graphs were one-component and analog except SKO, which was a three-component, digital station in operation
during the summer of 1988 only. Central volcanoes, fissure swarms and faults of the South Iceland Seismic
zone (between the stations IR, HB, SL, HL, and HE) are taken from the map of Einarsson and Sæmundsson
(1987). M is the Mýrdalsjökull glacier, El the Eldgjá fissure, and Ey the Eyjafjallajökull volcano. – Yfirlitskort
af megineldstöðvum, eldstöðvakerfum og skjálftamælistöðvum (þríhyrningar) á Suðurlandi á rannsóknartíma-
bilinu. Stafræn stöð á Skógaheiði (SKO) var einungis í gangi sumarið 1988.
The Katla volcano is an off-rift volcano, covered
by the glacier Mýrdalsjökull, and located in the vol-
canic flank zone in South Iceland (Figure 1). The vol-
canoes in this zone are quite varied, both with regard
to eruptive products and structure. Their products
are of transitional alkalic composition (Jakobsson,
1972; 1979) and they generally lack the rifting struc-
tures dominating the structure of the central volca-
noes of the axial rifting zone farther north and north-
east (Sæmundsson, 1978). Katla has produced mainly
transitional alkalic basalt lavas and tephra (Meyer et
al. 1985; Steinþórsson et al., 1985), but more silicic
rocks are known from nunataks in the glacier (Jóhann-
esson et al., 1982). A caldera, 10 km 13 km in diam-
eter, mapped beneath the glacier by radio echo sound-
ing (Björnsson et al., this issue), is underlain by a zone
of low P-velocity and high S-wave attenuation inter-
preted as a magma chamber at a depth of less than
60 JÖKULL No. 49