Source: VolcanoDiscovery.com - By T, 10/21/12
&md5=07dfe8b6d95048b4bd076c4eadfb935b?file=uploads%2Fpics%2F121021_1310.png&width=1000m&height=600m&bodyTag=<body bgcolor%3D"black">&wrap=<a href%3D"javascript%3Aclose()%3B"> | <%2Fa>&md5=72f36e29d33da094e341609ced8a2952 "Location of quakes in the TFZ (Iceland Met Office)")
&md5=bb844310190b815dc60c605447b5394b?file=uploads%2Fpics%2F121021_1310-2.png&width=1000m&height=600m&bodyTag=<body bgcolor%3D"black">&wrap=<a href%3D"javascript%3Aclose()%3B"> | <%2Fa>&md5=c66ccb5d9e0018c93ec7c9300bc8e11d "Time and magnitude of quakes in the TFZ (Iceland Met Office)")
A strong seismic swarm started shortly before midnight GMT in the Tjörnes Fracture Zone (TFZ) north of Iceland.
During the first 12 hours, about 300 quakes greater than magnitude 1 occurred at various depths ranging between 1 and 13 km, including 47 greater than magnitude 3. The largest was a widely felt M5.2 event in 10,8 km depth. Most quakes are located between the north coast of Iceland and the small island of Grimsey. A submarine volcano is known from a location north of Grimsey that erupted in 1372.
A weaker swarm yesterday around noon preceded the current one. Earthquakes, mostly of tectonic origin, are frequent in the TFZ, but since it is also near the volcanic rift zone, a magmatic component cannot be ruled out. At present, the nature of the quakes (purely seismic or magma intrusion) is not known.
