S wave -- a shadow zone appears when the velocity suddenly decreases 103-180 degrees from the epicenter. Describe the differences between P and S waves. P waves expand and contract, can move through liquid solid and gas. S wave moves up and down or side to side moves through only solids.
Optimal conditions to see the northern lights in Iceland is when skies are clear and dark (away from the city lights, in cold temperature and ideally from mid-September to mid-April.
Reykjavik itself receives between 4 â 5 hoursâ daylight, ensuring spectacular views of the Northern Lights (Aurora Borealis). Itâs an incredible time to explore Iceland and discover why tours such as the Land of the Northern Lights and Northern Lights Exploration are so unforgettable!