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.
In Iceland â especially far up in the north it is possible to see the beautiful Aurora. The best time is in October to April each year when we have clear sky and cold weather. It is ideal due the fact it is between two continents and also because all the great location Iceland has for seeing the the Northern lights.he best time is in October to April each year when we have clear sky and cold weather. It is ideal due the fact it is between two continents and also because all the great location Iceland has for seeing the the Northern lights.