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.
Advice on Northern Lights Itinerary (February 2014) - Iceland Forum. Advice on Northern Lights Itinerary (February 2014) London, United... Iâm mid-way through planning a week-long independent visit to Iceland in February 2014 with âintentionâ of seeing the Northern Light. Would like to see the Icelandic wilderness and the top attractions without it all being too hectic.