Shallow eartquakes are mostly originated at non-fractured areas, like the ones that occur near Mt. Herðubreið, where fault-plane solutions have indicated the formation of strike-slip faults.
Grunnir jarðskjálftar verða aðallega á nánast ósprungnum svæðum milli sprungusveimanna, t.a.m. við Herðubreið, þar sem brotlausnir jarðskjálfta benda til sniðgengishreyfinga á NA-lægum sprungum.