The swarm of small earthquakes continues as molten rock is shifting in the 15-km long NE-SW linear oriented underground dike.
Over the past 6 hours, the low-intensity quakes have peaked at the maximum strength ranging between M 2-3 and less. The magma-filled intrusion stretches from old volcanic craters (zone of crustal weakness) to the NE of Grindavik, through the town and south into the sea.
Scientists estimate the location of magma in the area north of Grindavík, between Sundhnúk and Hagafell. Magma is believed to be right in this area due to the most intense quake activity and significant rapid ground deformation.
The latest statistics indicate magma at very shallow levels, likely less than 500 meters under the surface.
It is also worth noting that recently formed cracks through the town follow the old crack from 1957, as visible in the former Grindavík map and occur on top of the 1957 crack.
The crack is a result of the ground displacement due to magma propagation within the underground dike.
Aerial historical photographs depict that there has been construction right in the area of old cracks. Fissures have come as a result of volcanic activity over the past 2400 years due to the divergent tectonic settings of Iceland. Plates are moving apart, forming graben-horst features resulting from extension, or pulling of the crust and allowing magma to rise toward the surface.
Source: RUV 15 November