The volcanic zone of Iceland can be divided into several volcanic systems.  Each system typically
has a central volcano with a magma chamber underneath and a caldera in the middle.  A swarm of fissures
usually cuts the central volcano and extends 50-100 km in both directions along the volcanic zone.
The Krafla volcanic system is indicated with purple colour. (Map from Einarsson 1991, slightly modified).

Recent earthquakes

Einarsson, P. 1991. Earthquakes and present-day tectonism in Iceland.  Tectonophysics 189: 261-279.

Einarsson, P. & K. Sæmundsson 1987.  Earthquake epicenters 1982-1985 and volcanic systems in Iceland.  In: Th. Sigfússon (ed.): Í hlutarins eðli: Festschrift for Þorbjörn Sigurgeirsson.  Menningarsjóður, Reykjavík (map).