Assessment - 27 April 2010 22:40
Overall assessment: Plume elevations and magma discharge levels remain
similar to the preceding four days of activity. Lava continues to flow
north from the eruption site toward the head of the Gígjökull glacier.
Despite light ash-fall occurring up to 45 km west of the eruption site,
today’s explosive activity and ash production represents a fraction of
conditions during the height of the eruption (14-17 April). There are
no measurable indications that the eruption is about to end.
Seismic tremor: Intensity comparable to the preceding four days of
eruptive activity.
Earthquakes: No locatable seismicity has been recorded today beneath
Eyjafjallajökull.
GPS deformation: Horizontal displacement towards the centre of the
volcano, in addition to vertical subsidence. These observations are
consistent with deflation of a magma reservoir beneath
Eyjafjallajökull.
Magma flow: No measurements possible today; however, the intensity of
the eruption suggests that the discharge level is similar to the
preceding four days (i.e. 20-40 tonnes ^s-1).
Meltwater: Continuing discharge of water from Gígjökull due to ice-melt
at the eruption site. Discharge at the old Markarfljót bridge, 18 km
from Gígjökull, is estimated at ~100 m^3 ^s-1, of which ~30 m^3 s-1 is
baseflow.
Other remarks: No measurable geophysical changes within the Katla
volcano.
Based on: IMO seismic monitoring; IES-IMO GPS monitoring; IMO river
gauges; information from local police; and aerial observations over the
eruption site.
The above is based on
status report issued collectively by IMO and the Institute of Earth Sciences at 19:00 this evening.
