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.
NORTHERN LIGHTS ICELAND WHEN TO GO The best time to see the northern lights in Iceland is from October to April when the sky is clear and the temperature is below zero.If you are planning on coming to Iceland to see the northern lights, you must keep in mind that there is no guarantee that you will see them.ORTHERN LIGHTS ICELAND WHEN TO GO The best time to see the northern lights in Iceland is from October to April when the sky is clear and the temperature is below zero.