Causes:
Constructive plate boundary --> rising convection currents --> tensional force --> North American Plate and Eurasian Plate move apart/ diverge (process: sea-floor spreading along Mid-Atlantic Ridge) --> pressure builds up on the plates --> cracks/ lines of weaknesses develop --> magma rises up --> volcanic ash and lava flow out from the crater. This is the occurrence of volcanic eruption
Case study: Iceland eruptions in 2010
1st eruption: March 2010
2nd eruption: April 2010
Negative impacts
Melted ice water from the glacier --> rise in sea level by 3m on 14 April --> rushing water broke a section of Iceland's main coastal ring road near Reykjavik (the capital)
Volcanic ash --> blown to extensive areas --> lowers visibility --> disrupts (better not to use the word "affect") air traffic, e.g. over 63,000 flights were cancelled in 23 European countries like the UK, Norway, Denmark