The earthquake of August 14, 1784, is considered to be the largest historical earthquake in Iceland (M=7.1). Its causative fault has been unknown except for the general area. Contemporary accounts mention that large fissures were formed in the northern part of the Holt district. The largest fractures found in this part of the seismic zone can be traced as a faint N-S system for a distance of 8 m. We assume that this is the expression of the 1784 causative fault.
Maps of the 1630 and 1784 faults are presented at the spring meeting of the Geoscience Society of Iceland  and will be published in a paper shortly.