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.
Experience a wonder of nature in Iceland. The Northern Lights (or Aurora Borealis) are among the most spectacular phenomena on earth â and Iceland is the perfect place to see them. Our Northern Lights tours and packages offer an incredible winter holiday, where you can combine hunting for Northern Lights with a range of fantastic winter activities and excursions into Icelandic nature.