GMT explosive activity increased again and the plume rose to about 7.5 km height. The increased activity was observed for about 20 minutes, then the activity dropped down at 21:15 GMT and increased again at 21:
45 GMT. This pulsating activity is also clearly seen on tremor plots (click to enlarge) from near seismic stations, i.e. at Grímsfjall, located 5 km east of the eruption site
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