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.
Unforgettable experience. The Northern Lights tour in Iceland takes you to see a spectacular natural phenomenon which happens during the winter months. The Northern Lights, also known as Aurora Borealis, are caused by the interaction of particles from the sun with the upper atmosphere near the North Pole.Northern Lights in Iceland are visible during the winter months, from September to April.The locations visited during the Northern Lights tour vary from day to day depending on weather conditions. Because this tour is weather dependent, sightings are not guaranteed.orthern Lights in Iceland are visible during the winter months, from September to April.