The British Geological Survey says there was a magnitude 5.4 earthquake in the area in 1984.
It describes that year's event as "significant".
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The whale was rescued last week and helped back into the sea. Environmentalists "sad" to find it had subsequently died.
Another largely cloudy and murky day with a chance of a few brighter spells in the west.
Victims of crime are being let down in some areas by poor investigations, a policing watchdog has said.