Jökull - 01.06.2000, Page 65

Páll Einarsson and Bryndís Brandsdóttir
Figure 3. Map of epicenters in the Mýrdalsjökull area 1978-1985 with epicentral errors less than 5 km. Sub-
glacial topography is from Björnsson et al, this issue. – Upptakakort jarðskjálfta við Mýrdalsjökul 1978-1985.
Landslag undir jöklinum er samkvæmt gögnum Helga Björnssonar o. fl., í þessu hefti.
ever, especially since 1991 (Halldórsson and Guð-
mundsson, 1994). Many earthquakes were felt north
of Eyjafjallajökull in 1994. The sequence was lo-
cated beneath the NE flank of the volcano (Guð-
mundsson, personal communication 1994) and was
interpreted as the result of an intrusion by Dahm and
Brandsdóttir (1997) based on reverse faulting focal
mechanisms. This interpretation is also supported
by tilt measurements at Fimmvörðuháls reported by
Tryggvason (2000). A similar occurrence of increased
seismicity, tilt and inflation indicated a dyke intrusion
beneath the south flank of Eyjafjallajökull in 1999
(Sturkell et al., 2000).
The Katla and Goðabunga centers, together with
the Eyjafjallajökull volcano, appear to define an E-W
structure. This trend is also strengthened by the fis-
sure swarm of the Eyjafjallajökull volcano contain-
ing Postglacial eruptive fissures both east and west
of the summit. These volcanoes also appear to be
sympathetic in their activity. It is quite common that
64 JÖKULL No. 49